1987 Vol. 5, No. 4
column
Display Method:
1987, 5(4): 1-13.
Abstract:
Storm deposits or tempestites have been recognized in Upper Carboniferious Series(Taiyuan Formation) shallow marine carbonate rocks around Jiaozuo Mines, Western Henan, in which the thickness of individual beds is generally 10-30cm, occasionally up to 50cm, and it shows a characteristic sedimentary sequence. From bottom to top they are:( 1 ) Erosional basement, which was truncated or undulated at the underlying sediments by storm induced wave and current, may show irregular variations. The wave length of the undulatory sole is about 16-40cm with 2-9cm in amplitude. In a few cases, some gutter casts-like structures would be found in the sole.( 2 ) Basal lag with normal grading limestone. The lag deposites are mainly composed of Brachiopoda, Anthozoa and Crinoidea debris with a few of whole Fusulinida, Anthozoa, Articulata, Crinoidea, Ostracoda, Estheria, Bryozoa body fossils and algae as well.( 3 ) Middle laminated unit. One or two of the sedimentary structures such as parallel lamination, wave ripple cross-lamination or hummocky cross-bedding may be recorded in the sections but varied in different depositional types. In addition, some vertical traces which are similar to escape structures may also occur within the laminated unit.( 4 ) Wackestone or Mudstone with trace fossils usually constitute the top unit of a whole storm bed. Zoophycos is the typical trace in these units and can be clearly distinguished as Z. simple form, Z. pelleted form and Z. fat form. They commonly associated with . The bioturbated bed may be subdivided into four grades depending on the bioturbation:(a) sporadic bioturbation, it only contains a few numbers of trace fossils and isolated unrecognized traces;(b) weakly bioturbated, i. e. the distinguishable and unrecognized traces are more than that of(a) in quantity;(c) medium bioturbated, in which the distinguishable traces are abundant with parts of mottled structures:(d) strongly bioturbated, chiefly consists of mottled structures which are good indicators of animal intensive activties. Apart from trace fossils, the top unit usually contains numerous body fossils such as Quasifusulina, Schwagerina, Pseudoschwagerina, Caninia, Lophophyllum, Syringopora, Dictyoclostus Choristitcs, Chonetes, Phricodothysis, Stenoscima, Magini-fera and Eomaginifera,etc. In terms of the sequence features, sedimentary and biogenic structures, four storm-generated depositional types in the limestone from Taiyuan Formation of Jiaozuo Mines are described as follows: Type A generally consists of basement lag and graded limestone in its lower subunit and the thickness is usually 2-6cm, the upper subunit is mainly wackestone(about 22cm thick) and associated with intensive bioturbation(commonly 6cm thick). The depositional water depth of this type was probably near storm wave base. Type B is composed of lower subunit recorded by basement lag and graded limestone with about 3-8cm thick, and the middle subunit(2-25cm thick) shows well developed hummocky cross-bedding or parallel laminations and the upper subunit(about 12cm thick) characterized by wackestone or mudstone and medium bioturbation as well as abundant Zoophycos. They are presumably deposited in an area near the middle-lower part between tair weather wave base and storm wave base. Type C has lower subunit(about 5cm thick) of basement lag and normal graded limestone and has upper subunit of wackestone, in which they are both lack of the laminated and bioturbated zone and it indicats that the deposited water depth was progressively shallowing and might be accumulated in the middle-upper position between fair wave base and storm wave base. Finally, type D(about 25cm thick) only includes lower normal graded coquinoid lage and upper wackestone. The trace fossils are rare or even absent, reflecting the water-depth got shallowed further, probably near the fair weather wave base in where the traces of living animal might be easily destroyed by wave or current at this environmental setting.
Storm deposits or tempestites have been recognized in Upper Carboniferious Series(Taiyuan Formation) shallow marine carbonate rocks around Jiaozuo Mines, Western Henan, in which the thickness of individual beds is generally 10-30cm, occasionally up to 50cm, and it shows a characteristic sedimentary sequence. From bottom to top they are:( 1 ) Erosional basement, which was truncated or undulated at the underlying sediments by storm induced wave and current, may show irregular variations. The wave length of the undulatory sole is about 16-40cm with 2-9cm in amplitude. In a few cases, some gutter casts-like structures would be found in the sole.( 2 ) Basal lag with normal grading limestone. The lag deposites are mainly composed of Brachiopoda, Anthozoa and Crinoidea debris with a few of whole Fusulinida, Anthozoa, Articulata, Crinoidea, Ostracoda, Estheria, Bryozoa body fossils and algae as well.( 3 ) Middle laminated unit. One or two of the sedimentary structures such as parallel lamination, wave ripple cross-lamination or hummocky cross-bedding may be recorded in the sections but varied in different depositional types. In addition, some vertical traces which are similar to escape structures may also occur within the laminated unit.( 4 ) Wackestone or Mudstone with trace fossils usually constitute the top unit of a whole storm bed. Zoophycos is the typical trace in these units and can be clearly distinguished as Z. simple form, Z. pelleted form and Z. fat form. They commonly associated with . The bioturbated bed may be subdivided into four grades depending on the bioturbation:(a) sporadic bioturbation, it only contains a few numbers of trace fossils and isolated unrecognized traces;(b) weakly bioturbated, i. e. the distinguishable and unrecognized traces are more than that of(a) in quantity;(c) medium bioturbated, in which the distinguishable traces are abundant with parts of mottled structures:(d) strongly bioturbated, chiefly consists of mottled structures which are good indicators of animal intensive activties. Apart from trace fossils, the top unit usually contains numerous body fossils such as Quasifusulina, Schwagerina, Pseudoschwagerina, Caninia, Lophophyllum, Syringopora, Dictyoclostus Choristitcs, Chonetes, Phricodothysis, Stenoscima, Magini-fera and Eomaginifera,etc. In terms of the sequence features, sedimentary and biogenic structures, four storm-generated depositional types in the limestone from Taiyuan Formation of Jiaozuo Mines are described as follows: Type A generally consists of basement lag and graded limestone in its lower subunit and the thickness is usually 2-6cm, the upper subunit is mainly wackestone(about 22cm thick) and associated with intensive bioturbation(commonly 6cm thick). The depositional water depth of this type was probably near storm wave base. Type B is composed of lower subunit recorded by basement lag and graded limestone with about 3-8cm thick, and the middle subunit(2-25cm thick) shows well developed hummocky cross-bedding or parallel laminations and the upper subunit(about 12cm thick) characterized by wackestone or mudstone and medium bioturbation as well as abundant Zoophycos. They are presumably deposited in an area near the middle-lower part between tair weather wave base and storm wave base. Type C has lower subunit(about 5cm thick) of basement lag and normal graded limestone and has upper subunit of wackestone, in which they are both lack of the laminated and bioturbated zone and it indicats that the deposited water depth was progressively shallowing and might be accumulated in the middle-upper position between fair wave base and storm wave base. Finally, type D(about 25cm thick) only includes lower normal graded coquinoid lage and upper wackestone. The trace fossils are rare or even absent, reflecting the water-depth got shallowed further, probably near the fair weather wave base in where the traces of living animal might be easily destroyed by wave or current at this environmental setting.
1987, 5(4): 25-30.
Abstract:
In the oceanic sediments generally contained two kinds of glassy grains(the size less than a millimeter), i. e. the microtektites which are extraterrestrial material, and seafloor volcanic glass which are terrestrial material. Because both of them are very different in properties, should not lump together. The tektite distributed widely all over the world is still attended by geologists, meteorists and space scientists, an important research object in various sciences. The microtektites distributed widely in Atlantic, Indian Ocean and Pacific are also same material because they have same physical, chemical properties, surface feature and formed age, which they were divided into different strewn fields. Important characteristics in chemical composition of microtektites are that their contents of SiO2 are stable,contents of MgO are higher, and contents of Na2O and MnO are very low. In addition, also microtektites contained Os, Ir, etc. important trace elements, which are suggested that originate from extraterrestrial. Different microtektites in each strewn fields have variety physical properties, surface feature and formed age. The basaltic glasses in ocean floor are volcanic products in the affirmative. Their properties in colour, type, structure, etc. suggest that they had passed ejected and melted process. Important characteristics in chemical composition of basaltic glasses are that their contents of MgO are very low,contents of Na2O, K2O and MnO are all higher, which simlar to chemical composition of volcanic glasses on the continent. The "bomb-shaped glass" different from microtektites and basaltic glasses. They are mainly composed of SiO2 in chemical composition(contents of SiO2 90%), contents of other oxides are all low. The results of neutron activation analysis indicate that they contained only a few of trace elements(Fe, Co, Au, etc.) none coutain Os, Ir, et. cparticular trace elements. Therefore, they are not extraterrestrial material, and perhaps they are products ejected by volcano from ocean bottom.
In the oceanic sediments generally contained two kinds of glassy grains(the size less than a millimeter), i. e. the microtektites which are extraterrestrial material, and seafloor volcanic glass which are terrestrial material. Because both of them are very different in properties, should not lump together. The tektite distributed widely all over the world is still attended by geologists, meteorists and space scientists, an important research object in various sciences. The microtektites distributed widely in Atlantic, Indian Ocean and Pacific are also same material because they have same physical, chemical properties, surface feature and formed age, which they were divided into different strewn fields. Important characteristics in chemical composition of microtektites are that their contents of SiO2 are stable,contents of MgO are higher, and contents of Na2O and MnO are very low. In addition, also microtektites contained Os, Ir, etc. important trace elements, which are suggested that originate from extraterrestrial. Different microtektites in each strewn fields have variety physical properties, surface feature and formed age. The basaltic glasses in ocean floor are volcanic products in the affirmative. Their properties in colour, type, structure, etc. suggest that they had passed ejected and melted process. Important characteristics in chemical composition of basaltic glasses are that their contents of MgO are very low,contents of Na2O, K2O and MnO are all higher, which simlar to chemical composition of volcanic glasses on the continent. The "bomb-shaped glass" different from microtektites and basaltic glasses. They are mainly composed of SiO2 in chemical composition(contents of SiO2 90%), contents of other oxides are all low. The results of neutron activation analysis indicate that they contained only a few of trace elements(Fe, Co, Au, etc.) none coutain Os, Ir, et. cparticular trace elements. Therefore, they are not extraterrestrial material, and perhaps they are products ejected by volcano from ocean bottom.
1987, 5(4): 44-55.
Abstract:
Many siliceous carbonate coal balls, occurring in the lignite seam of some Tertiary coal-bearing basins within the Cenozoic coal-accumulation belt in South China, have been found recently by the authors. They occur in young horizons, distributed extensively and composition varies with areas, but the inner plant structure is preserved vell. They are first reported in China. By extensive observation in the fields and study such as coal petrographic microscope, mineral X-ray powder diffraction, spectrum analysis, petrochemistry and paleobotanic anatomy. It has been proved that the coal ball in the Oligocene-Pliocene lignite seam is specific type of coal ball which mainly consists of silica and carbonate. The mineral consisting of the coal ball vary with the coal-forming conditions such as paleostructure of basin, paleogeography, paleoclimate and paleoplant. The major minerals are quartz, calcite or siderite. The minor and trace minerals are montmorillonite, dolomite and pyrite etc. SiO2 content in the siliceous coal ball is generally more than 66%; CaO content in the calcareous one more than 45%; Fe2O3 content in the ferric one more than 50%; SiO2 content in the ferric-siliceous one more than 76%, FeO more than 7%; CaO content in the ferric-calcareous one more than 23%, Fe2O3+FeO more than 9%. Carbon content in the all kinds of coal balls is generally 13.62%. The contents of the major coal ball-forming elements are about equal to that of the coal seam top, more than those of the lignite, and vary with the kinds of mineral composition of coal balls. But the content of trace element Ti in the coal ball is less than that of the coal seam top, and in prosimity to the lignite. The contents of other trace elements such as Ba, B, Pb, Sn, Ga, Cr, Xi, Mo, Y, Cu, Zn, Zr, Y, Yb, Sr, etc. generally consist with that of the coal seam top and the lignite. All coal balls consist of mineralized coal-forming plants. Their plantic species are mainly Pinus, with minor Pterocarya,, Acer and Fagus etc. The process of the coal balls forming may be summarized as follows: During coal-forming action from stage of peatification to stage of diagenesis, first synsedimentary plant branches underwent oxidation, their woods were gradually decayed and their shape was changed by compression; then the ground water solution, containing the substances of the coal seam top such as silica, calcium and iron, intruded into the coal seam, and the coal-forming plants were filled with and replaced by this mineralized solution, and the coal balls, whose inner structures are well-preserved, were formed. Since these coal balls were found, the following work can be made up for morphological study of Tertiary coalforming plants: Anatomical study of their cell structures, determination of their position in plant classification and reconstruction of their evolutional relation; besides, those are helpful to study coal-forming environments such as paleostructure, paleoclimate and paleogeography.
Many siliceous carbonate coal balls, occurring in the lignite seam of some Tertiary coal-bearing basins within the Cenozoic coal-accumulation belt in South China, have been found recently by the authors. They occur in young horizons, distributed extensively and composition varies with areas, but the inner plant structure is preserved vell. They are first reported in China. By extensive observation in the fields and study such as coal petrographic microscope, mineral X-ray powder diffraction, spectrum analysis, petrochemistry and paleobotanic anatomy. It has been proved that the coal ball in the Oligocene-Pliocene lignite seam is specific type of coal ball which mainly consists of silica and carbonate. The mineral consisting of the coal ball vary with the coal-forming conditions such as paleostructure of basin, paleogeography, paleoclimate and paleoplant. The major minerals are quartz, calcite or siderite. The minor and trace minerals are montmorillonite, dolomite and pyrite etc. SiO2 content in the siliceous coal ball is generally more than 66%; CaO content in the calcareous one more than 45%; Fe2O3 content in the ferric one more than 50%; SiO2 content in the ferric-siliceous one more than 76%, FeO more than 7%; CaO content in the ferric-calcareous one more than 23%, Fe2O3+FeO more than 9%. Carbon content in the all kinds of coal balls is generally 13.62%. The contents of the major coal ball-forming elements are about equal to that of the coal seam top, more than those of the lignite, and vary with the kinds of mineral composition of coal balls. But the content of trace element Ti in the coal ball is less than that of the coal seam top, and in prosimity to the lignite. The contents of other trace elements such as Ba, B, Pb, Sn, Ga, Cr, Xi, Mo, Y, Cu, Zn, Zr, Y, Yb, Sr, etc. generally consist with that of the coal seam top and the lignite. All coal balls consist of mineralized coal-forming plants. Their plantic species are mainly Pinus, with minor Pterocarya,, Acer and Fagus etc. The process of the coal balls forming may be summarized as follows: During coal-forming action from stage of peatification to stage of diagenesis, first synsedimentary plant branches underwent oxidation, their woods were gradually decayed and their shape was changed by compression; then the ground water solution, containing the substances of the coal seam top such as silica, calcium and iron, intruded into the coal seam, and the coal-forming plants were filled with and replaced by this mineralized solution, and the coal balls, whose inner structures are well-preserved, were formed. Since these coal balls were found, the following work can be made up for morphological study of Tertiary coalforming plants: Anatomical study of their cell structures, determination of their position in plant classification and reconstruction of their evolutional relation; besides, those are helpful to study coal-forming environments such as paleostructure, paleoclimate and paleogeography.
1987, 5(4): 66-77.
Abstract:
Halaalate Mountain, situated in the northwest margin of the Junggar Basin in Xinjiang, Crops out Middle Carboniferous Series. The opinions about the age of this stratum are different because there are only a few fossils in it. B. A. Obarugieve considered that it was Silurian. Mr. Hao Fuguang held that it was Devonian in 1964. Area Geological Team of Xinjiang defined it as Lower and Middle Carboniferous Series in 1979. In terms of fossil assemblages found and absolute age of rocks by K-Ar, we put these strata to Middle Carboniferous Series and Lover Permian Series, and set up the new sequence. Halaalate Formation: According to lithological characters, it can be divided into three members:Lower Member is mainly involved grey-green volcaniclastic and volcanic rock(andesite and basalt) with a few limestone lenticles, Medium Member the grey-black sandy shale with fine grained sandstones, Upper Member grey medium-course grained sandstones. The fossil assemblages in the formation are as follows: Brachiopoda: Enteletina unclata Jin et Liao, Kutorginella Tentoria Jin et Liao, Waagenoconcha aff. sarytchevae(Bened), Fusulina: Fseudoslaffella cf. varsonofievae Rauser These fossils often occured in Bashkirira Age. The absolute age of rocks in the formation is 282-310Ma. So, the Halaalate Formation should belong to Middle Carboniferous Series. Aladeyiksai Formation: It overlies the Halaalate Formation. The contact between two formations is conformable It contains fossils: Fusulina: Pseudosiaffella timonica, Profusulinella parafittsi and Profusulinella trisulcata. These fossils belong to Moscovian Age. Therefore, Aladayikesai Formation must lie on Halaalate Formation. The Lower Member of Jiamuhe Formation; There are some fossils in the bottom beel of the Member. They are: Bryozoa: Fistulepora sp. and Fenestella sp. Hydroid polyp; Malacostroma sp. The value of absolute age of the rock is 241-267Ma. The member should belong to Lower Permian Series, but not Lower Carboniferous Series. According to the characters of paleoecology, rock assemblage and combined relation among elements and other marks in the stratum of the Halaalate Mountain area, the sedimentary facies were referred to as: Halaalate Formation: The lower member represents neritic deposit associated with much volcanic emanation, the medium member littoral sub-closed lagoon environment in which the sea water was desalted, the upper member littoral environment. Aladeyikesai age suggests clastic deposit in littoral tidal flat environment. The Lower Member of Jiamuhe Formation indicates the environment of a continental volcanic emanation, which was companyed with short ingression in the earlier stage and became continental flood deposit in the front of mountains in the later. The evolutional history of the sedimentary facies: Marine transgression took place in Medium Carboniferous Epoch. Halaalate area was inundated by sea water, and became wide littoral trench associated with vigorous volcanic activity. The velocity of deposition was faster. Then the sea water from north to south. Sub-closed lagoon environment occured in this area. Because fresh water from terrigenous area flowed into the lagoon, water in the lagoon was desalted. After that, on the effect of vibration of the sea water, the lagoon destroyed and evolved littoral beach until littoral tidal flat environment. In Late Carboniferous Epoch, this area was raised and became mountains. Then the area suffered disintegration. During Early Permian Epoch, volcanoes erupted again, geographic undulation increased and very thick flood deposits(drifted material laved) on the volcanic rocks.
Halaalate Mountain, situated in the northwest margin of the Junggar Basin in Xinjiang, Crops out Middle Carboniferous Series. The opinions about the age of this stratum are different because there are only a few fossils in it. B. A. Obarugieve considered that it was Silurian. Mr. Hao Fuguang held that it was Devonian in 1964. Area Geological Team of Xinjiang defined it as Lower and Middle Carboniferous Series in 1979. In terms of fossil assemblages found and absolute age of rocks by K-Ar, we put these strata to Middle Carboniferous Series and Lover Permian Series, and set up the new sequence. Halaalate Formation: According to lithological characters, it can be divided into three members:Lower Member is mainly involved grey-green volcaniclastic and volcanic rock(andesite and basalt) with a few limestone lenticles, Medium Member the grey-black sandy shale with fine grained sandstones, Upper Member grey medium-course grained sandstones. The fossil assemblages in the formation are as follows: Brachiopoda: Enteletina unclata Jin et Liao, Kutorginella Tentoria Jin et Liao, Waagenoconcha aff. sarytchevae(Bened), Fusulina: Fseudoslaffella cf. varsonofievae Rauser These fossils often occured in Bashkirira Age. The absolute age of rocks in the formation is 282-310Ma. So, the Halaalate Formation should belong to Middle Carboniferous Series. Aladeyiksai Formation: It overlies the Halaalate Formation. The contact between two formations is conformable It contains fossils: Fusulina: Pseudosiaffella timonica, Profusulinella parafittsi and Profusulinella trisulcata. These fossils belong to Moscovian Age. Therefore, Aladayikesai Formation must lie on Halaalate Formation. The Lower Member of Jiamuhe Formation; There are some fossils in the bottom beel of the Member. They are: Bryozoa: Fistulepora sp. and Fenestella sp. Hydroid polyp; Malacostroma sp. The value of absolute age of the rock is 241-267Ma. The member should belong to Lower Permian Series, but not Lower Carboniferous Series. According to the characters of paleoecology, rock assemblage and combined relation among elements and other marks in the stratum of the Halaalate Mountain area, the sedimentary facies were referred to as: Halaalate Formation: The lower member represents neritic deposit associated with much volcanic emanation, the medium member littoral sub-closed lagoon environment in which the sea water was desalted, the upper member littoral environment. Aladeyikesai age suggests clastic deposit in littoral tidal flat environment. The Lower Member of Jiamuhe Formation indicates the environment of a continental volcanic emanation, which was companyed with short ingression in the earlier stage and became continental flood deposit in the front of mountains in the later. The evolutional history of the sedimentary facies: Marine transgression took place in Medium Carboniferous Epoch. Halaalate area was inundated by sea water, and became wide littoral trench associated with vigorous volcanic activity. The velocity of deposition was faster. Then the sea water from north to south. Sub-closed lagoon environment occured in this area. Because fresh water from terrigenous area flowed into the lagoon, water in the lagoon was desalted. After that, on the effect of vibration of the sea water, the lagoon destroyed and evolved littoral beach until littoral tidal flat environment. In Late Carboniferous Epoch, this area was raised and became mountains. Then the area suffered disintegration. During Early Permian Epoch, volcanoes erupted again, geographic undulation increased and very thick flood deposits(drifted material laved) on the volcanic rocks.
1987, 5(4): 90-95.
Abstract:
In recent years, based on the systematically study of more than 3500 samples of Lover Paleozoic carbonate rock of the surface sections and the deep wells of the plain in North China, author found some typical sedimentary textures. They can indicate sedimentary environments, diagenetic history and the important indicators of prospect for minerals. According to the study on the characteristics of minerals forming the textures, the process of intraclasts-forming and the replacements between different minerals, and observation in the fields, the discussions is proposed about the relation between the textures and the sedimentary and/or diagenetic environments in this paper.( 1 ) Indicator of evaporative tidal flat and gypsum deposit; dolomite bearing positiveelongation chalcedonic concretionary gypsum In Linqing area of Shandong, dolomite bearing positive elongation chalcedonic concretionary gypsum was found in drill holes at the stratum bearing gypsum deposit lower part of Lower Majiagou Formation in Ordovician. The environment formed positive elongation chalcedony is dry and evaporative in climate and high in ion concentration and pH value, it is very different from the normal environment formed negative elongation chalcedony. So, if positive elongation chalcedony was found in sedimentary rock we should focus our attention at looking for evaporative beds. As pointed above, positive elongation chalcedony not only can response evaporative tidal flat environment, but also play a indicator in looking for evaporative deposit.(2 ) The significance of psendocrystal of gypsum-type calcite in reflecting environments Based on the systematic observation of pseudocrystal of gypsum-type calcite in the Ordovician carbonate rock of North China, It is pointed out that gypsums were formed in different diagenetical stages. Some were formed in penecontemporaneous or early diagenetic stage. The rest were formed in epigonetic or hypergene stage and have not relation to the sedimentary environments of surrounding rocks. So, the former may be used as the indicator for environments of evaporative tidal flat, but the later cannot be used as indicator facies.( 3 ) The indicator of environment of tidal flat: the high energy oolite with multilayer-film ironstone In the middle part of Xuzhuang Formation of Cambrian in Hongdong of Shanxi and Laiwu Shangdong, there are the deposits of sparry oolite limestone bearing terrigenous grain interbeding with calcareous fine-grained quartzose sandstone. The main composition in this rock is the oolite with special inter-texture of 20-30 fine and closed concentric rings of micritic calcite. There is a very thin layer film of ironstone between the rings. The oolite was formed in the intertidal high energy zone. Owing to rising and falling of tidal water frequently, the oolitic nucleus or immature oolites were deposited and exposed, every new ring of oolites must be oxidized by oxidation and surrounded by a very thin film of ironstone. As the result, the high energy oolite with multilayer-film ironstone is formed. The oolite is a special product of tidal movement in wet and warm climate and is a indicator of tidal sediment and also a important basis for studying the position of ancient coast line. Three types of sedimentary texture mentioned above all were formed in special sedimentary or diagenetic environments. Studying these textures is important not only in the theory of sedimentology, but also in the exploration of sedimentary mineral product.
In recent years, based on the systematically study of more than 3500 samples of Lover Paleozoic carbonate rock of the surface sections and the deep wells of the plain in North China, author found some typical sedimentary textures. They can indicate sedimentary environments, diagenetic history and the important indicators of prospect for minerals. According to the study on the characteristics of minerals forming the textures, the process of intraclasts-forming and the replacements between different minerals, and observation in the fields, the discussions is proposed about the relation between the textures and the sedimentary and/or diagenetic environments in this paper.( 1 ) Indicator of evaporative tidal flat and gypsum deposit; dolomite bearing positiveelongation chalcedonic concretionary gypsum In Linqing area of Shandong, dolomite bearing positive elongation chalcedonic concretionary gypsum was found in drill holes at the stratum bearing gypsum deposit lower part of Lower Majiagou Formation in Ordovician. The environment formed positive elongation chalcedony is dry and evaporative in climate and high in ion concentration and pH value, it is very different from the normal environment formed negative elongation chalcedony. So, if positive elongation chalcedony was found in sedimentary rock we should focus our attention at looking for evaporative beds. As pointed above, positive elongation chalcedony not only can response evaporative tidal flat environment, but also play a indicator in looking for evaporative deposit.(2 ) The significance of psendocrystal of gypsum-type calcite in reflecting environments Based on the systematic observation of pseudocrystal of gypsum-type calcite in the Ordovician carbonate rock of North China, It is pointed out that gypsums were formed in different diagenetical stages. Some were formed in penecontemporaneous or early diagenetic stage. The rest were formed in epigonetic or hypergene stage and have not relation to the sedimentary environments of surrounding rocks. So, the former may be used as the indicator for environments of evaporative tidal flat, but the later cannot be used as indicator facies.( 3 ) The indicator of environment of tidal flat: the high energy oolite with multilayer-film ironstone In the middle part of Xuzhuang Formation of Cambrian in Hongdong of Shanxi and Laiwu Shangdong, there are the deposits of sparry oolite limestone bearing terrigenous grain interbeding with calcareous fine-grained quartzose sandstone. The main composition in this rock is the oolite with special inter-texture of 20-30 fine and closed concentric rings of micritic calcite. There is a very thin layer film of ironstone between the rings. The oolite was formed in the intertidal high energy zone. Owing to rising and falling of tidal water frequently, the oolitic nucleus or immature oolites were deposited and exposed, every new ring of oolites must be oxidized by oxidation and surrounded by a very thin film of ironstone. As the result, the high energy oolite with multilayer-film ironstone is formed. The oolite is a special product of tidal movement in wet and warm climate and is a indicator of tidal sediment and also a important basis for studying the position of ancient coast line. Three types of sedimentary texture mentioned above all were formed in special sedimentary or diagenetic environments. Studying these textures is important not only in the theory of sedimentology, but also in the exploration of sedimentary mineral product.
1987, 5(4): 107-114.
Abstract:
The pleistocene dolomite crops out the erosion flat of a intertidal zone and on the cliff of the supratidal zone of Paipu in the Hainan Island as the first recent dolomite discovered in China, 1981. The total thickness is more than 4m. It can be subdivided into 7 beds, the upward succession is as follows: pebbled coarse sandy bed(nondiagenetic) i dolomitic fine grained stone dolomitic tubular fine sandstone; dolomitic medium grained sandstone, dolomitic tubular fine sandstone, dolomitic pebbled coarse sandstone, greyyellow medium sandstone. Terrigenous quartz, feldspar rock fragments are associated with dolomite and Echinoidea, Foraminifera fragments are visible. The content and grain size of detritus are different in beds each. SEM observation indicates that the dolomite crustals in the matrix are perfect rhombohed-rons. The dolomites from the second dolomite bed are of teeth-shoped(Fig.l). The matrix from the 7th bed contains not only dolomite but also calcite. According to the characters of rocks of every bed and the data of Wang Kuozhung's "Discovery of pleistocene dolomite and its formative environment in Hainan Island, China, 1982", the Paipu section shows a sequence of seashore lagoon, seashore river mouth and river deposits. The dolomitic tubules are developed in the 3th and 5th beds of the section(Fig.3). Length of the tubules are 10-20 cm, sections are circular or elliptical in shape and 1-2 cm in diameter. There are two kinds of tubular intrastructures; one is the compact texture composed micritic dolomites and the other is the structure composed of coarse sands in the center and fine micrites in the rim. The energy dispersive spectrometry of the dolomites in the tube indicates that; CaO content is higher than that of typical dolomites, but MgO is lower, FeO content is 4-5%(Table 1), Fe/Mg values from 0.23-0.36. The X-ray diffractometry shows the characteristical speak(104) spacing of tube dolomite is 2.896A, corresponding to 2.899A of iron-bearing dolomite. The ordering analyses by XRD give 2θ 34.85-35.8° for(015) and 29 36.75-37.9° for(110), the integrating intensity ratio ranging from 0.4-0.64(Table 2). Tie origin of dolomitic tubules has previously been explained to be the dolomitization of plants. But the author suggests presently they are filling and replacement of burrow. The evidences are: 1. the shape of dolomitic tubules are consistent. They are single tubes without any branching; 2. the wall of the tube is smooth which can be separated as weatering; 3. the form of the tubeles are similar and the size differences are small,it suggests that they are hiding holes of same organism; 4. the intrastructure of the tubules the compactive ones are abandoned holes filling carbontes, the other is suggested that the finegrained rim is formed by animal incretion, and the coarse material to be the fillings caused by the tidalwave disturbances. According to the form of the burrow it may be a kind of indicating trace fossil-skolithos nearby seashore intertidal zone facies. According to isotopic data, the date of dolomites formation may be from 32000-35000 year. The place of the sea level in the past may be same as present, both are inter-supratidal zone. The climate of the area belongs to the tropical monsoon island's. Dry-humid monsoon are alternate, and annual rainfall is 1237.3mm/a, mostly from June to October. The barrier sands often present on the shore and their perviousness is good. In the dry monsoon, dry-hot climate result in evaporation of seawater, the seawater continually flow to loose sand-gravel sediments of the shore by the capillary effect resulting the sand space filling seawater. In the rain-monsoon, a lot of fresh-water sink down and mixed with the migrating seawater, resulting saltness decrease but the Mg/Ca ratio does not vary. Under the appropriate condition, the dolomites will be formed. In the area, the crystal grain of dolomites are 10-30 microns and the crystal form appears rhombs and better transparency, but the evaporites are not present. Put it briefly, they had showed t
The pleistocene dolomite crops out the erosion flat of a intertidal zone and on the cliff of the supratidal zone of Paipu in the Hainan Island as the first recent dolomite discovered in China, 1981. The total thickness is more than 4m. It can be subdivided into 7 beds, the upward succession is as follows: pebbled coarse sandy bed(nondiagenetic) i dolomitic fine grained stone dolomitic tubular fine sandstone; dolomitic medium grained sandstone, dolomitic tubular fine sandstone, dolomitic pebbled coarse sandstone, greyyellow medium sandstone. Terrigenous quartz, feldspar rock fragments are associated with dolomite and Echinoidea, Foraminifera fragments are visible. The content and grain size of detritus are different in beds each. SEM observation indicates that the dolomite crustals in the matrix are perfect rhombohed-rons. The dolomites from the second dolomite bed are of teeth-shoped(Fig.l). The matrix from the 7th bed contains not only dolomite but also calcite. According to the characters of rocks of every bed and the data of Wang Kuozhung's "Discovery of pleistocene dolomite and its formative environment in Hainan Island, China, 1982", the Paipu section shows a sequence of seashore lagoon, seashore river mouth and river deposits. The dolomitic tubules are developed in the 3th and 5th beds of the section(Fig.3). Length of the tubules are 10-20 cm, sections are circular or elliptical in shape and 1-2 cm in diameter. There are two kinds of tubular intrastructures; one is the compact texture composed micritic dolomites and the other is the structure composed of coarse sands in the center and fine micrites in the rim. The energy dispersive spectrometry of the dolomites in the tube indicates that; CaO content is higher than that of typical dolomites, but MgO is lower, FeO content is 4-5%(Table 1), Fe/Mg values from 0.23-0.36. The X-ray diffractometry shows the characteristical speak(104) spacing of tube dolomite is 2.896A, corresponding to 2.899A of iron-bearing dolomite. The ordering analyses by XRD give 2θ 34.85-35.8° for(015) and 29 36.75-37.9° for(110), the integrating intensity ratio ranging from 0.4-0.64(Table 2). Tie origin of dolomitic tubules has previously been explained to be the dolomitization of plants. But the author suggests presently they are filling and replacement of burrow. The evidences are: 1. the shape of dolomitic tubules are consistent. They are single tubes without any branching; 2. the wall of the tube is smooth which can be separated as weatering; 3. the form of the tubeles are similar and the size differences are small,it suggests that they are hiding holes of same organism; 4. the intrastructure of the tubules the compactive ones are abandoned holes filling carbontes, the other is suggested that the finegrained rim is formed by animal incretion, and the coarse material to be the fillings caused by the tidalwave disturbances. According to the form of the burrow it may be a kind of indicating trace fossil-skolithos nearby seashore intertidal zone facies. According to isotopic data, the date of dolomites formation may be from 32000-35000 year. The place of the sea level in the past may be same as present, both are inter-supratidal zone. The climate of the area belongs to the tropical monsoon island's. Dry-humid monsoon are alternate, and annual rainfall is 1237.3mm/a, mostly from June to October. The barrier sands often present on the shore and their perviousness is good. In the dry monsoon, dry-hot climate result in evaporation of seawater, the seawater continually flow to loose sand-gravel sediments of the shore by the capillary effect resulting the sand space filling seawater. In the rain-monsoon, a lot of fresh-water sink down and mixed with the migrating seawater, resulting saltness decrease but the Mg/Ca ratio does not vary. Under the appropriate condition, the dolomites will be formed. In the area, the crystal grain of dolomites are 10-30 microns and the crystal form appears rhombs and better transparency, but the evaporites are not present. Put it briefly, they had showed t
1987, 5(4): 127-136.
Abstract:
17,21-secohopanes(C(24)-C(27)) and 8,14-secohopanes(C27-C30) are two types of tetracyclic terpanes which were found recently. They have also been found when we studied the biomarker hydrocarbons of Mesozoic, Cenozoic crude oils and source rocks in Shaanganning Basin( Shaanxi-Gansu-Ningxia ) and Baise Basin(Guangxi Province) by using GC-MS. This paper deals with the geochemical signification of these tetracyclic terpanes by combining the geochemical analytic data in terrestrial basins mentioned above. It is very interesting for the distribution of 17,21-secohopanes(C24-C27) series in the Early Tertiary source rocks in Baise Basin, Guangzi Province. They only appreaed in coals and source rocks which is immature and the type of organic matter belonging to Ⅳ and Ⅱ, but they are absent in I type's and Ⅱ_A type's source rocks. It is suggested that the distribution phenomenon is related to the microbial degradation which happened in the special period of Tertiary in this basin by the synthetic analysis of several geochemical data. These tetracyclic terpanes are passibled the products of biodegradation by broken E circle of precusor hopenes, and successively reducing into relative alkanes by geochemical action in the early diagenesis. This type of tetracyclic terpanes play an important marker part in geochemical charater in the oil/rock correlation of Baise Basin. The origin of 8,14-secohopane(C27-C30) series is mainly related to heating action, they were derived from hopane type of pentacyclic triterpanes by broken C circle in latter It is suggested that the richness of 8,14-secohopanes can be used to reflect the maturation of sedimentary organic matter from our researching results in Shaanganning basin. We have come to the conclusion that C30-secohopane/4-methyl-C20 sterane can be used as a new molecular parameter reflecting the mature level of sedimentary organic matter according to our researching results, the ratio increasing with the mature level of organic matters. Moreover, the M/E414 mass chromatogram reflecting the richness of C30-secohopane and 4-methyl-C29 sterane can also be used as the "fingerpriter fig." which can be used for oil/rock correlation. It is suggested that vast appearance of 8,14-secohopanes may be related with higher heat action, because it's absent for 8,14-secohopanes in the Early Tertiary crude oils and source rocks of Baise Basin, but there are more contents of 8,14-secohopanes in the Mesozoic crude oils and source rocks which had higher mature level in Shaanganning Basin. Therefore, 8,14-secohopane series perhaps is more suitable for studying the mature level of sedimentary organic matter which is relative older in geological age.
17,21-secohopanes(C(24)-C(27)) and 8,14-secohopanes(C27-C30) are two types of tetracyclic terpanes which were found recently. They have also been found when we studied the biomarker hydrocarbons of Mesozoic, Cenozoic crude oils and source rocks in Shaanganning Basin( Shaanxi-Gansu-Ningxia ) and Baise Basin(Guangxi Province) by using GC-MS. This paper deals with the geochemical signification of these tetracyclic terpanes by combining the geochemical analytic data in terrestrial basins mentioned above. It is very interesting for the distribution of 17,21-secohopanes(C24-C27) series in the Early Tertiary source rocks in Baise Basin, Guangzi Province. They only appreaed in coals and source rocks which is immature and the type of organic matter belonging to Ⅳ and Ⅱ, but they are absent in I type's and Ⅱ_A type's source rocks. It is suggested that the distribution phenomenon is related to the microbial degradation which happened in the special period of Tertiary in this basin by the synthetic analysis of several geochemical data. These tetracyclic terpanes are passibled the products of biodegradation by broken E circle of precusor hopenes, and successively reducing into relative alkanes by geochemical action in the early diagenesis. This type of tetracyclic terpanes play an important marker part in geochemical charater in the oil/rock correlation of Baise Basin. The origin of 8,14-secohopane(C27-C30) series is mainly related to heating action, they were derived from hopane type of pentacyclic triterpanes by broken C circle in latter It is suggested that the richness of 8,14-secohopanes can be used to reflect the maturation of sedimentary organic matter from our researching results in Shaanganning basin. We have come to the conclusion that C30-secohopane/4-methyl-C20 sterane can be used as a new molecular parameter reflecting the mature level of sedimentary organic matter according to our researching results, the ratio increasing with the mature level of organic matters. Moreover, the M/E414 mass chromatogram reflecting the richness of C30-secohopane and 4-methyl-C29 sterane can also be used as the "fingerpriter fig." which can be used for oil/rock correlation. It is suggested that vast appearance of 8,14-secohopanes may be related with higher heat action, because it's absent for 8,14-secohopanes in the Early Tertiary crude oils and source rocks of Baise Basin, but there are more contents of 8,14-secohopanes in the Mesozoic crude oils and source rocks which had higher mature level in Shaanganning Basin. Therefore, 8,14-secohopane series perhaps is more suitable for studying the mature level of sedimentary organic matter which is relative older in geological age.
1987, 5(4): 137-146.
Abstract:
By emission spectroscopy with powder sample, the trace metallic elements of 72 oil samples from Tertiary Qianjian and Xingouzui Formations of Jianhan Salt Lake Basin are systematically determined qualitatively and quantitatively. According to the analyze results, there are more than 13 trace metallic elements in the oil of Jianghan basin and they are cobalt(Co), silicon(Si), iron(Fe), germanium(Ge), zirconium(Zr), magnesium(Mg), molybdenum(Mo), lead(Pb), chromium(Cr), nickel(Ni), titanium(Ti), calcium(Ca), vanadium(V) etc. The quantitative analysis of the 13 trace metallic elements reveals that the elements content in all oil-bearing columnar sections distributes regularly both in vertical and lateral directions. Except lead and magnesium, the contents of the remaining 11 trace metallic elements increase with the increase of specific gravity, viscosity, sulphur content, asphaltene, resin, content of porphyrin compounds etc. of oil. In general, in the process of migration of oil and gas, polar component and heavy metallic elements in the petroleum can be selectively absorbed by mineral grains, which induces to decreasing these heavy components and increasing light components along the direction of petroleum migration, i.e. resulting in a regular distribution of trace metallic elements. On the basis of experimental distribution data, we can use this general regularity to judge the migration direction of petroleum in a local place. The contents of trace metallic elements of petroleum decrease with the increase of the stratum age and the petroleum maturity. It is especially worth while noting that the contents of the trace metallic elements, such as molybdenum and cobalt, in the immatured heavy oils of the first member of Qianjiang Formation(Eq) are 15 times higher than those of the underlying strata, whereas germanium is present only in the first member of Qianjiang Formation(Eq). These features are characteristics of the immatured oil of the first member of Qianjiang Formation, namely, high contents of tracing metallic elements, especially molybdenum, cobalt, germanium, chromium, nickel, vanadium, and it is an evident indication differing from the underlying oil-bearing strata. Consequently, the kinds and content variation of trace metallic elements in oil can be used to distinguish the reservoirs of different horizons and to develop reservoir correlation in new exploring regions. In the oil samples of the fourth member of Qianjiang Formation(Eq4) and Xinggouzui Formation(Ex), there are only 2 samples containing porphyrin compounds, in all the other 36 samples have been not found porphyrin compounds yet. The oil in these two formations contains nickel(4.34 ppm 0.94 ppm) generally. The metallic nickel does not combine with tetrapyrrole structure of porphyrins, but is present in a free form. Certainly, the high stratigraphic temperature and high maturity of oil may also result in the destruction of tetrapur-role structure and let metallic nickel remain there. The average V/Ni ratio of the oil in Jianghan Salt Lake Basin is 0.12. It is higher than the ratios of other oil fields of our country, such as Shengli(0.038), Gudao(0.038), Renqiou(0.047), Yumen(0.001), Kalamayi(0.029), and Baxian(0.077). But it is far lower than the V/Ni ratios of foreign marine oils,for example, 19 times less than Romashkin(2.381) of U.S.S.R, 85 times less than the oil fields(10.230) of Venezuela. This coincides with the characteristics of continental oil of our country.
By emission spectroscopy with powder sample, the trace metallic elements of 72 oil samples from Tertiary Qianjian and Xingouzui Formations of Jianhan Salt Lake Basin are systematically determined qualitatively and quantitatively. According to the analyze results, there are more than 13 trace metallic elements in the oil of Jianghan basin and they are cobalt(Co), silicon(Si), iron(Fe), germanium(Ge), zirconium(Zr), magnesium(Mg), molybdenum(Mo), lead(Pb), chromium(Cr), nickel(Ni), titanium(Ti), calcium(Ca), vanadium(V) etc. The quantitative analysis of the 13 trace metallic elements reveals that the elements content in all oil-bearing columnar sections distributes regularly both in vertical and lateral directions. Except lead and magnesium, the contents of the remaining 11 trace metallic elements increase with the increase of specific gravity, viscosity, sulphur content, asphaltene, resin, content of porphyrin compounds etc. of oil. In general, in the process of migration of oil and gas, polar component and heavy metallic elements in the petroleum can be selectively absorbed by mineral grains, which induces to decreasing these heavy components and increasing light components along the direction of petroleum migration, i.e. resulting in a regular distribution of trace metallic elements. On the basis of experimental distribution data, we can use this general regularity to judge the migration direction of petroleum in a local place. The contents of trace metallic elements of petroleum decrease with the increase of the stratum age and the petroleum maturity. It is especially worth while noting that the contents of the trace metallic elements, such as molybdenum and cobalt, in the immatured heavy oils of the first member of Qianjiang Formation(Eq) are 15 times higher than those of the underlying strata, whereas germanium is present only in the first member of Qianjiang Formation(Eq). These features are characteristics of the immatured oil of the first member of Qianjiang Formation, namely, high contents of tracing metallic elements, especially molybdenum, cobalt, germanium, chromium, nickel, vanadium, and it is an evident indication differing from the underlying oil-bearing strata. Consequently, the kinds and content variation of trace metallic elements in oil can be used to distinguish the reservoirs of different horizons and to develop reservoir correlation in new exploring regions. In the oil samples of the fourth member of Qianjiang Formation(Eq4) and Xinggouzui Formation(Ex), there are only 2 samples containing porphyrin compounds, in all the other 36 samples have been not found porphyrin compounds yet. The oil in these two formations contains nickel(4.34 ppm 0.94 ppm) generally. The metallic nickel does not combine with tetrapyrrole structure of porphyrins, but is present in a free form. Certainly, the high stratigraphic temperature and high maturity of oil may also result in the destruction of tetrapur-role structure and let metallic nickel remain there. The average V/Ni ratio of the oil in Jianghan Salt Lake Basin is 0.12. It is higher than the ratios of other oil fields of our country, such as Shengli(0.038), Gudao(0.038), Renqiou(0.047), Yumen(0.001), Kalamayi(0.029), and Baxian(0.077). But it is far lower than the V/Ni ratios of foreign marine oils,for example, 19 times less than Romashkin(2.381) of U.S.S.R, 85 times less than the oil fields(10.230) of Venezuela. This coincides with the characteristics of continental oil of our country.
1987, 5(4): 14-24.
Abstract:
The 3rd Member of Shahejie Formation Oligocene is the sediments during the deep depressing period of Dongying Basin, Shandong Province. At that time, the basin centre was a west-dip gentle slope of prodelta where a dark mudstone with maximum thickness up to 600 meters was deposited. A lot of elongate and/or lenticular clastic rock bodies have been discoveried in this set of dark mudstone. The studies based on drilling data indicate that the lithological characters of the clastic rock body are as following:( 1 ) It predominantly is sandstone with intraclastic texture and mud-block silt-block rudstone and mud-block grain rock with intraclastic texture as well as dolosiltite, and it is common that angular and stripped argillaceous rent block mixed into these rocks.( 2 ) When the mud is more contentrative(forming argillaceous rent block,especially thin interbeds), the rhyotaxitic structure in the mud is common.( 3 ) The rhythm of the rock consists of the rigid raft in the upper part and the laminar flow zone in the lower part. All the characters indicate that sediments are transported and deposited by cohesive plastic(Bingham substance) flow(namely, debris flow). Based on sedimentary characters, the intraclastic debris folws in the prodelta can be subdivided into sandy debris flow, silty debris flow, carbonate debris flow and argillaceous debris flow. Based on fabric and lithologic characters, the rhythm of the preceding three debris flows can be divided into five division: floating mud-block rudite division, mixed seriate rudite division, parallel fabric division, flow laminae division and pillow lump division. The rhythm of argillaceous debris flow sediments can be divided into three division: sliding sand lump and mud-block division, rhyotaxitic structure division and pillow lump division. The floating mud-block rudite division and the mixed seriate rudite division(sliding sandy lump and mudb-lock division) are just the rigid raft(plug flow) in the division of rheology, and the parallel fabric division and flow laminae division(rhyotaxitic structure division) are just the laminar flow zone. The formation of these debris flows are caused by the fast depositional rate and the unstability the sediments in the high-constructive delta area. The river mouth bar and the far bar with sediments of higher specific gravity prograded and deposited on soft argillaceous sediments with lower specific gravity deposited originally in a prodelta. Such a unstability of gravity resulted in slide which evolved to debris flow. There are necessary conditions for the formation of debris flow in the high-constructive delta. The oil exploration in Dongying Basin indicated that the debris flow clastic rock body distributed broadly in the gentle slope area of prodelta. The sandy debris flow sediments, with lower mud content, higher porosity and permeability, high pressure(in the abnormal high pressure zone), appeared to be very well in oil prospect, and to be an important object for explorating occult oil reservoir.
The 3rd Member of Shahejie Formation Oligocene is the sediments during the deep depressing period of Dongying Basin, Shandong Province. At that time, the basin centre was a west-dip gentle slope of prodelta where a dark mudstone with maximum thickness up to 600 meters was deposited. A lot of elongate and/or lenticular clastic rock bodies have been discoveried in this set of dark mudstone. The studies based on drilling data indicate that the lithological characters of the clastic rock body are as following:( 1 ) It predominantly is sandstone with intraclastic texture and mud-block silt-block rudstone and mud-block grain rock with intraclastic texture as well as dolosiltite, and it is common that angular and stripped argillaceous rent block mixed into these rocks.( 2 ) When the mud is more contentrative(forming argillaceous rent block,especially thin interbeds), the rhyotaxitic structure in the mud is common.( 3 ) The rhythm of the rock consists of the rigid raft in the upper part and the laminar flow zone in the lower part. All the characters indicate that sediments are transported and deposited by cohesive plastic(Bingham substance) flow(namely, debris flow). Based on sedimentary characters, the intraclastic debris folws in the prodelta can be subdivided into sandy debris flow, silty debris flow, carbonate debris flow and argillaceous debris flow. Based on fabric and lithologic characters, the rhythm of the preceding three debris flows can be divided into five division: floating mud-block rudite division, mixed seriate rudite division, parallel fabric division, flow laminae division and pillow lump division. The rhythm of argillaceous debris flow sediments can be divided into three division: sliding sand lump and mud-block division, rhyotaxitic structure division and pillow lump division. The floating mud-block rudite division and the mixed seriate rudite division(sliding sandy lump and mudb-lock division) are just the rigid raft(plug flow) in the division of rheology, and the parallel fabric division and flow laminae division(rhyotaxitic structure division) are just the laminar flow zone. The formation of these debris flows are caused by the fast depositional rate and the unstability the sediments in the high-constructive delta area. The river mouth bar and the far bar with sediments of higher specific gravity prograded and deposited on soft argillaceous sediments with lower specific gravity deposited originally in a prodelta. Such a unstability of gravity resulted in slide which evolved to debris flow. There are necessary conditions for the formation of debris flow in the high-constructive delta. The oil exploration in Dongying Basin indicated that the debris flow clastic rock body distributed broadly in the gentle slope area of prodelta. The sandy debris flow sediments, with lower mud content, higher porosity and permeability, high pressure(in the abnormal high pressure zone), appeared to be very well in oil prospect, and to be an important object for explorating occult oil reservoir.
1987, 5(4): 31-43.
Abstract:
These hydromica minerals described in this paper include well-known dioctahedral 10A sericite, hydromuscovite, illite and micalike clay minerals, twenty major samples from Inner Mongolia, Hebei, Shanxi, Jiangsu, Zhejiang, Jiangxi and Hubei have been studied by XRD, DTA, TG and IR techniques and some detail results of their thermal properties have been presented in this text. At the same time, a few of them have also been treated with chemical and eletron microscope analysis. They are nonexpansible, pure or essentially pure and come from weathered environment, sedimentary rocks as well as metamorphic rocks respectivly. The hydromica samples have been distinguished into 2M1, 1M, 1Md, 2M1 + 1M polytypes. Besides common reflection, in XRD patterns the 2M1 polytype minerals are characterized by 3.87 A( W),3.74A(W-m),3.49 A(m), 3.20 A(m), 2.86 A(W-m), 2.79 A(W-m),and 2.13 A(W) etc. refraction, but the 1M polytype by 4.32 A(W-m), 3.65 A(m-W), 3.06 A(m-s), 2.92 A(W) and 2.68 A(W-m ) etc. The former mostly occur in the altered rocks at medium-high temperature zone and the later in sedimentary or altered rocks of low-medium temperature, The XRD reflection for 1Md minerals is rare and weaker. These 1Md minerals usually present in weathered and sedimentary products. The DTA curves of the hydromica minerals generally show two endothermic peaks, the first low temperature peak at about 100℃ is of moving off absorbed and interlayer water and correspondingly loses 0.2-4% weight the second medium-temperature peak at 500-900℃ or above is attributed to dehydroxylation, appearing with 4.6-6.2% weight loss. On these DTA curves, generally speaking, the higher-temperature thermal effect that represents structural desintegration(break) and phase transformation does not clearly appear. The IR and XRD graphs of the samples, heated at 30℃/min to 800℃ or900℃ till lossing hydroxyl, show that their basic structure still remains stable, only as heated to about 1100℃ or 1200℃ , do they change into Al-rich andalusite or spinel. On a routine identification of hydromica minerals, the following is suggested; it can be known "sericite" as whose XRD pattern approximates that of muscovite, the temperature of dehydroxyl peak in the DTA curve is above 700℃ and the mineral apperance is aphanitic and microscalyj it is in terms of " hydromuscovite " or "hydromica" that the(ool) refraction of XRD pattern is broader and weaker and the temperature of dehydroxyl peak between 600℃ and 700℃ if the temperature below 600℃, especially below 550℃, it is suitable to call the samples "illite" for it usually is epigene and its crystallization is poor, sometimes with expansible layers.
These hydromica minerals described in this paper include well-known dioctahedral 10A sericite, hydromuscovite, illite and micalike clay minerals, twenty major samples from Inner Mongolia, Hebei, Shanxi, Jiangsu, Zhejiang, Jiangxi and Hubei have been studied by XRD, DTA, TG and IR techniques and some detail results of their thermal properties have been presented in this text. At the same time, a few of them have also been treated with chemical and eletron microscope analysis. They are nonexpansible, pure or essentially pure and come from weathered environment, sedimentary rocks as well as metamorphic rocks respectivly. The hydromica samples have been distinguished into 2M1, 1M, 1Md, 2M1 + 1M polytypes. Besides common reflection, in XRD patterns the 2M1 polytype minerals are characterized by 3.87 A( W),3.74A(W-m),3.49 A(m), 3.20 A(m), 2.86 A(W-m), 2.79 A(W-m),and 2.13 A(W) etc. refraction, but the 1M polytype by 4.32 A(W-m), 3.65 A(m-W), 3.06 A(m-s), 2.92 A(W) and 2.68 A(W-m ) etc. The former mostly occur in the altered rocks at medium-high temperature zone and the later in sedimentary or altered rocks of low-medium temperature, The XRD reflection for 1Md minerals is rare and weaker. These 1Md minerals usually present in weathered and sedimentary products. The DTA curves of the hydromica minerals generally show two endothermic peaks, the first low temperature peak at about 100℃ is of moving off absorbed and interlayer water and correspondingly loses 0.2-4% weight the second medium-temperature peak at 500-900℃ or above is attributed to dehydroxylation, appearing with 4.6-6.2% weight loss. On these DTA curves, generally speaking, the higher-temperature thermal effect that represents structural desintegration(break) and phase transformation does not clearly appear. The IR and XRD graphs of the samples, heated at 30℃/min to 800℃ or900℃ till lossing hydroxyl, show that their basic structure still remains stable, only as heated to about 1100℃ or 1200℃ , do they change into Al-rich andalusite or spinel. On a routine identification of hydromica minerals, the following is suggested; it can be known "sericite" as whose XRD pattern approximates that of muscovite, the temperature of dehydroxyl peak in the DTA curve is above 700℃ and the mineral apperance is aphanitic and microscalyj it is in terms of " hydromuscovite " or "hydromica" that the(ool) refraction of XRD pattern is broader and weaker and the temperature of dehydroxyl peak between 600℃ and 700℃ if the temperature below 600℃, especially below 550℃, it is suitable to call the samples "illite" for it usually is epigene and its crystallization is poor, sometimes with expansible layers.
1987, 5(4): 56-65.
Abstract:
A series of changes take place during each of stages after sedimentation of gypsum-salt. Researches on these changes are of significance, which are helpful not only to the analyses of depositional condition but also to the determination of prospecting criteria and the evaluation of potentiality. This paper mainly involves investigations on such problems as the syngenesis, diagenesis, anadiagenesis and supergene alteration of Triassic gypsum-salt in Quxian County, Sichuan Province. Some carbonates, such as dolomite and magnesite, are a associated minerals of the Triassic evaporite which chiefly contains gypsum, anhydrite and polyhalite. Observations in detail find out that some anhydrites taking the pseudomorph after idiomorphic crystals of gypsum reserve the syndepositional zoning of gypsum, it means that the syngenetic CaSO4 mineral is gypsum. The sedimentary environment of gypsum-salt in this region may be deduced from various date about sedimentary condition of the syngenetic gypsum and anhydrite and from the results of sedimentary facies analysis. During of syngenesis, calcite associated with gypsum was replaced by Mg-rich brine and changed into micritic dolomite with the brine became more concentrated, and while CO32-rich fresh water supplemented gypsum also would be replaced by dolomite owing to the raise of pH value and the existence of organism. At this stage, fresh water flowing into the basin might leach the former dissolvable salt and formed K-Mg-rich solution which might replace the gypsum of surface bed and promote the formation of thin-lagyr polyhalite interbeding with gypsum, mud and magnesite so that made up laminated structure. At the early period of diagenesis, as a result of the replacement of lime-mud matrix by Mg-rich pore brine, fine crystal dolomite occured and disseminated dissolvable salt minerals precipited in the interspace of gypsum. With the increase in depth of burial of sediments, gypsum dehydrated into anhydrite because of the raise of temperature and pressure. The anhydrite of filling type was formed while released solution. Containing a portion of CaSO4, went through diagenetic cracks. At the period of diagenesis, pore brine must have replaced carbonate to form nodular anhydrite, the characters of which, such as ellipsoidal shap, uniform size and directive distribution along layer, are as distinct form that of the cave filling and Sabkha replacement anhydrite. Moreover, unregular, veined and massire polyhatite, on which the replacement remanent texture of anhydrite can be watched,was formed below the surface sediments due to the infiltrate metasomatism by K-Mg-rich solution formed by leaching of dissolvable salt. At the period of supergene alteration changes more intense than at any other stages further are taken place in the gypsum-salt, because of the leaching process of sub-and-surface water. First and foremost, anhydrite hydrated into gypsum and associated dolomite was replaced with calcite, and with that dissolution-collapse breccia occured due to the collapse of its distal wall and intercalated bed after dissolution of gypsum-salt layer. This breccia is of complex composition and wide brecciated size range the fragments are cemented by secondary calcite and filled by mud. If these rocks cracked into fragments due to differential plastic deformation or tectonic strain, then the gypsum-salt among the fragments desolved and the fragments cemented by secondary calcite and filled by mud, so the crushed-desolved breccia would be formed. These breccias characterised by that the fragments arranged follow the stratification plane without obvious displacement and showed deformational structures. Finally, degypsification happened, i, e., both surface water and shallow-subsurface water bearing great quantities of HCO3- replaced anhydrite into calcite. Gypsum in the interspace of crush breccia of dolomite was replaced by secondary calcite to form crushing-replacement breccia. Research on various changes of gypsum-salt after its sedimentation is an important aspect of changes taken place investigation for salt deposit. For instaace，in the light of its during the syngenesis and diagenesis, one debate its sedimentary condition and saltness of brine at that time, and according to the eztent of its supergene alteration，combining with the analyses of tectonic,and caver canditions,one also canon，geollogists working determine the region favourable forhydrogeo logicalits reservation.From now work.on salt deposit should pay more attentions to this work.
A series of changes take place during each of stages after sedimentation of gypsum-salt. Researches on these changes are of significance, which are helpful not only to the analyses of depositional condition but also to the determination of prospecting criteria and the evaluation of potentiality. This paper mainly involves investigations on such problems as the syngenesis, diagenesis, anadiagenesis and supergene alteration of Triassic gypsum-salt in Quxian County, Sichuan Province. Some carbonates, such as dolomite and magnesite, are a associated minerals of the Triassic evaporite which chiefly contains gypsum, anhydrite and polyhalite. Observations in detail find out that some anhydrites taking the pseudomorph after idiomorphic crystals of gypsum reserve the syndepositional zoning of gypsum, it means that the syngenetic CaSO4 mineral is gypsum. The sedimentary environment of gypsum-salt in this region may be deduced from various date about sedimentary condition of the syngenetic gypsum and anhydrite and from the results of sedimentary facies analysis. During of syngenesis, calcite associated with gypsum was replaced by Mg-rich brine and changed into micritic dolomite with the brine became more concentrated, and while CO32-rich fresh water supplemented gypsum also would be replaced by dolomite owing to the raise of pH value and the existence of organism. At this stage, fresh water flowing into the basin might leach the former dissolvable salt and formed K-Mg-rich solution which might replace the gypsum of surface bed and promote the formation of thin-lagyr polyhalite interbeding with gypsum, mud and magnesite so that made up laminated structure. At the early period of diagenesis, as a result of the replacement of lime-mud matrix by Mg-rich pore brine, fine crystal dolomite occured and disseminated dissolvable salt minerals precipited in the interspace of gypsum. With the increase in depth of burial of sediments, gypsum dehydrated into anhydrite because of the raise of temperature and pressure. The anhydrite of filling type was formed while released solution. Containing a portion of CaSO4, went through diagenetic cracks. At the period of diagenesis, pore brine must have replaced carbonate to form nodular anhydrite, the characters of which, such as ellipsoidal shap, uniform size and directive distribution along layer, are as distinct form that of the cave filling and Sabkha replacement anhydrite. Moreover, unregular, veined and massire polyhatite, on which the replacement remanent texture of anhydrite can be watched,was formed below the surface sediments due to the infiltrate metasomatism by K-Mg-rich solution formed by leaching of dissolvable salt. At the period of supergene alteration changes more intense than at any other stages further are taken place in the gypsum-salt, because of the leaching process of sub-and-surface water. First and foremost, anhydrite hydrated into gypsum and associated dolomite was replaced with calcite, and with that dissolution-collapse breccia occured due to the collapse of its distal wall and intercalated bed after dissolution of gypsum-salt layer. This breccia is of complex composition and wide brecciated size range the fragments are cemented by secondary calcite and filled by mud. If these rocks cracked into fragments due to differential plastic deformation or tectonic strain, then the gypsum-salt among the fragments desolved and the fragments cemented by secondary calcite and filled by mud, so the crushed-desolved breccia would be formed. These breccias characterised by that the fragments arranged follow the stratification plane without obvious displacement and showed deformational structures. Finally, degypsification happened, i, e., both surface water and shallow-subsurface water bearing great quantities of HCO3- replaced anhydrite into calcite. Gypsum in the interspace of crush breccia of dolomite was replaced by secondary calcite to form crushing-replacement breccia. Research on various changes of gypsum-salt after its sedimentation is an important aspect of changes taken place investigation for salt deposit. For instaace，in the light of its during the syngenesis and diagenesis, one debate its sedimentary condition and saltness of brine at that time, and according to the eztent of its supergene alteration，combining with the analyses of tectonic,and caver canditions,one also canon，geollogists working determine the region favourable forhydrogeo logicalits reservation.From now work.on salt deposit should pay more attentions to this work.
1987, 5(4): 78-89.
Abstract:
During the latest Permian(Changsingian), the Longmenshan region was situated ia the northwestern margin of the South China Sea, it belonged to a transitional zone between Yangtze Platform and Songpan-Garze Geosyncline. The fault basin of the Longmenshan zone underwent continuously submerge due to the influence of the vast Varictan movement and formed mainly the deeper water marginal sea trough, with NNE trend. The sediment is composed of mixed deposition by the carbonate and mud-siliceous, rare terrigenous clastic, partly contain abundant organic materials(bituminization) and pyrite, with horizontal bedding, rhythm bedding, knotty nodular and sheet crack sturctures etc. The biota is represented by the develop of planktonic fauans, such as ammonoids radiolariads, conodonts and siliceous facies brachipoda etc. According tothe type of rocks, sedimentary structure and biological assemblages etc.the latest Permian sedimentary facies can be divided into the following: 1 Deep water shelf facies The type of rocks is composed of dark grey thin to medium bedded micrite and siliceous micrits intercalated with calcareous shale and containing. They are a few of organic materials, pyrite and chert bands or blocks, and display horizontal bedding, lenticular bedding and knotty structure. The biota is represented by benthnic, plankonic and epiplanktonic mixed faunas, such as radiolarians, conodonts, siliceous facies brachiopods with thin-shelled and a few of thick-shelled brachoipods, solitary corals, foraminif ers etc. This facies may be considered as a transitional zone between the platform and the basin, in which the sea water was deeper, and the circulation of water current was moderate. It was formed in the slightly oxidizing to slightly reduction condition, and in the environment changed from lower energy to medium energy. 2 Slope facies The sediments are dark-gray to gray-black thin-bedded mud -bearing siliceous rocks, siliceous micrite intercalated with carbonaceous shale or black shale and characterized by distinct horizontal bedding and rhythm bedding as well as partly with intraformational slump-folds and faulted sturcture. They contain abundant organic materials(partly bituminizaed) and pyrite nodular. Fossils are rather monotonic and less in quantity in the facies, chiefly including planktonic and epiplanktonic faunas, such as ammonoids, conodonts, and some hemi-planktonic or benthonic faunas, such as non-fusuline foraminifers etc. This facies is proved to be slope zone between the shelf and the basin, in which the sea water was deeper and with restricted circulation and reduction condition. 3 Basin(or sea trough) facies It includs 3 zones of seeimentary facies:( 1 ) Lag zone of basin This facies is composed of gray-black thin-bedded mud-bearing siliceous rocks, carbonaceous radiolarites, siliceous micrite intercalated with carbonaceous shale. They are rich in organic materials(bituminization) and pyrite with horizontal bedding and rhythm bedding. The biota is characterized by abundant plankonic faunas such as ammonoids, conodonts and radiolarians. This facies is represented by the lag basin of the deep water, quite of water current and the reducing condition.(2 ) Rise zone of basin The siliceous micrite intercalated with calcareous shale is mainly the rock type, which is dark grey, thin to medium-bedded, with rhythm bedding. The faunas assemblage is composed of planktonic, epiplanktonic and a few benthonic faunas such as ammonoids conodonts and foraminifers etc. According to the characters of lithofacies and biofacies, it was a partly rise region of basin, in which the sea water was shallower with medium energy and the circulation of water current was better.( 3 ) Flowage zone of basin The zone is made up of dark grey thin-bedded siliceous radiolarite, siliceous micrite intercalate with montmorillonite-illite irregularly mixed layer clay rock. Some clay rock was formed under marine conditions by volcanic ash. It possesses rhythm bedding, knotty nodular and sheet cracks structures etc. The bio
During the latest Permian(Changsingian), the Longmenshan region was situated ia the northwestern margin of the South China Sea, it belonged to a transitional zone between Yangtze Platform and Songpan-Garze Geosyncline. The fault basin of the Longmenshan zone underwent continuously submerge due to the influence of the vast Varictan movement and formed mainly the deeper water marginal sea trough, with NNE trend. The sediment is composed of mixed deposition by the carbonate and mud-siliceous, rare terrigenous clastic, partly contain abundant organic materials(bituminization) and pyrite, with horizontal bedding, rhythm bedding, knotty nodular and sheet crack sturctures etc. The biota is represented by the develop of planktonic fauans, such as ammonoids radiolariads, conodonts and siliceous facies brachipoda etc. According tothe type of rocks, sedimentary structure and biological assemblages etc.the latest Permian sedimentary facies can be divided into the following: 1 Deep water shelf facies The type of rocks is composed of dark grey thin to medium bedded micrite and siliceous micrits intercalated with calcareous shale and containing. They are a few of organic materials, pyrite and chert bands or blocks, and display horizontal bedding, lenticular bedding and knotty structure. The biota is represented by benthnic, plankonic and epiplanktonic mixed faunas, such as radiolarians, conodonts, siliceous facies brachiopods with thin-shelled and a few of thick-shelled brachoipods, solitary corals, foraminif ers etc. This facies may be considered as a transitional zone between the platform and the basin, in which the sea water was deeper, and the circulation of water current was moderate. It was formed in the slightly oxidizing to slightly reduction condition, and in the environment changed from lower energy to medium energy. 2 Slope facies The sediments are dark-gray to gray-black thin-bedded mud -bearing siliceous rocks, siliceous micrite intercalated with carbonaceous shale or black shale and characterized by distinct horizontal bedding and rhythm bedding as well as partly with intraformational slump-folds and faulted sturcture. They contain abundant organic materials(partly bituminizaed) and pyrite nodular. Fossils are rather monotonic and less in quantity in the facies, chiefly including planktonic and epiplanktonic faunas, such as ammonoids, conodonts, and some hemi-planktonic or benthonic faunas, such as non-fusuline foraminifers etc. This facies is proved to be slope zone between the shelf and the basin, in which the sea water was deeper and with restricted circulation and reduction condition. 3 Basin(or sea trough) facies It includs 3 zones of seeimentary facies:( 1 ) Lag zone of basin This facies is composed of gray-black thin-bedded mud-bearing siliceous rocks, carbonaceous radiolarites, siliceous micrite intercalated with carbonaceous shale. They are rich in organic materials(bituminization) and pyrite with horizontal bedding and rhythm bedding. The biota is characterized by abundant plankonic faunas such as ammonoids, conodonts and radiolarians. This facies is represented by the lag basin of the deep water, quite of water current and the reducing condition.(2 ) Rise zone of basin The siliceous micrite intercalated with calcareous shale is mainly the rock type, which is dark grey, thin to medium-bedded, with rhythm bedding. The faunas assemblage is composed of planktonic, epiplanktonic and a few benthonic faunas such as ammonoids conodonts and foraminifers etc. According to the characters of lithofacies and biofacies, it was a partly rise region of basin, in which the sea water was shallower with medium energy and the circulation of water current was better.( 3 ) Flowage zone of basin The zone is made up of dark grey thin-bedded siliceous radiolarite, siliceous micrite intercalate with montmorillonite-illite irregularly mixed layer clay rock. Some clay rock was formed under marine conditions by volcanic ash. It possesses rhythm bedding, knotty nodular and sheet cracks structures etc. The bio
1987, 5(4): 96-106.
Abstract:
Observed the cores from 11 wells and the loggings from approximate 300 wells in 3rd Member of the Lower Tertiary Shahejie Formation in the west Huimin seg, and analyzed sedimentary facies, Linpan Delta and the Shanghe deepwater turbidite fan and other sedimentary environments were determined. Linpan Delta and the Shanghe turbidite fan have a lot of different characteristics in lithology, sedimentary structure, grain size, logging, and paleontological assemblage etc. The lobate Linpan Delta Paralleled the axis direction of Huimin seg, 35 kilometers in length, over 700 meters in accumulating thickness. The delta displays a reverse cycle on the whole vertical section. The reverse rhythm of the predelta and delta front consisted of grey mudstone and light grey siltstone, fine grained sandstone, about 8 meters in thickness, and appeared frequently; the normal rhythm of the delta plain consisted of light grey, and greyish green siltstone, fine grained sandstone, medium grained sandstone and brown mudstone, carbonaceous shale, 1-4 meters in thickness. The normal rhythm often overlaies the reverse one, constituting a complete delta composite rhythm. The maturity of sandstone composition is lower, the content of quartz 50-60%, feldspar 20-30%, rock fragment 10-20%, clay 5-10%. The maturity of its texture is higher, moderate-well sorted and grain supported texture. The grain size data indicate the feature of typical drawning-current. The probability graphs of the delta are two-lines which consits of suspension and saltation populations, CM diagram consists of segment QRS. There are many types of sedimentary structures, such as cross bedding, parallel stratification, and vegetable foot etc. The vertical sequence of the sedimentary stuctures reflects the delta porgradation towards lake centre, paleontological assemblages, SP curves and seismic sections all show the existence of the Linpan delta. The Shanghe deep-water turbidite fan is located in the front of Linpan Delta, irregular oval in shape, smaller in size, the area is about 10-20 km2. The frequent interbeded light grey, greyish brown muddy siltstone, siltstone, fine grained sandstone, and deep grey mudstone constituted a lot of normal rhythms, 0.5-5.5 meters in thickness. The maturity of the sandstone composition is relatively low, the content of quartz 40-60%, feldspar 15-30%, rock fragment 5-25%, clay 10-20%, having mud supported, pore-matrix cementation. The information of grain size shows the characteristic turbidite sedimentation, probability graphs are single line, CM diagram appears segment QR paralleled to C = M base line. The complete incomplete Bouma seqences and many kinds of base prints were developed. The deep and shallow fossils were associated, their types were monotonous and a few in quantity. There are many typical electric loggings and seismic responses of the Shanghe turbidite fan. In order to establish a local facies model quickly and accurately, and play a role in facies studying, to eliminate some artificial influnce, and to favor the dialogue between geologists, in this paper authors used the Markov chain to determine vertical relationship of the sedimentary sequence of the Linpan delta and the Shanghe deep-water turbidite fan and to establish the local facies models. Practice has indicated that the Markov chain is an effective method to establish local facies model, and it is suitable for rhythmical complex stratigraphic sequence. The steps of Markov chain established facies modle are following: 1. Observe stratigraphic section carefully, based on a varity of facies marks, determine facies with different characteristics and their relationship plotted relation diagram of facies change; 2. Count the whole number of facies changes and the number of facies changes from one into another, establish the matrix of facies change number, determine facies change probability of sequence; observed 3. Fix the facies change probability of random sequence; 4. Determine the diffe- rence of facies change probability between the observed and random sequences,
Observed the cores from 11 wells and the loggings from approximate 300 wells in 3rd Member of the Lower Tertiary Shahejie Formation in the west Huimin seg, and analyzed sedimentary facies, Linpan Delta and the Shanghe deepwater turbidite fan and other sedimentary environments were determined. Linpan Delta and the Shanghe turbidite fan have a lot of different characteristics in lithology, sedimentary structure, grain size, logging, and paleontological assemblage etc. The lobate Linpan Delta Paralleled the axis direction of Huimin seg, 35 kilometers in length, over 700 meters in accumulating thickness. The delta displays a reverse cycle on the whole vertical section. The reverse rhythm of the predelta and delta front consisted of grey mudstone and light grey siltstone, fine grained sandstone, about 8 meters in thickness, and appeared frequently; the normal rhythm of the delta plain consisted of light grey, and greyish green siltstone, fine grained sandstone, medium grained sandstone and brown mudstone, carbonaceous shale, 1-4 meters in thickness. The normal rhythm often overlaies the reverse one, constituting a complete delta composite rhythm. The maturity of sandstone composition is lower, the content of quartz 50-60%, feldspar 20-30%, rock fragment 10-20%, clay 5-10%. The maturity of its texture is higher, moderate-well sorted and grain supported texture. The grain size data indicate the feature of typical drawning-current. The probability graphs of the delta are two-lines which consits of suspension and saltation populations, CM diagram consists of segment QRS. There are many types of sedimentary structures, such as cross bedding, parallel stratification, and vegetable foot etc. The vertical sequence of the sedimentary stuctures reflects the delta porgradation towards lake centre, paleontological assemblages, SP curves and seismic sections all show the existence of the Linpan delta. The Shanghe deep-water turbidite fan is located in the front of Linpan Delta, irregular oval in shape, smaller in size, the area is about 10-20 km2. The frequent interbeded light grey, greyish brown muddy siltstone, siltstone, fine grained sandstone, and deep grey mudstone constituted a lot of normal rhythms, 0.5-5.5 meters in thickness. The maturity of the sandstone composition is relatively low, the content of quartz 40-60%, feldspar 15-30%, rock fragment 5-25%, clay 10-20%, having mud supported, pore-matrix cementation. The information of grain size shows the characteristic turbidite sedimentation, probability graphs are single line, CM diagram appears segment QR paralleled to C = M base line. The complete incomplete Bouma seqences and many kinds of base prints were developed. The deep and shallow fossils were associated, their types were monotonous and a few in quantity. There are many typical electric loggings and seismic responses of the Shanghe turbidite fan. In order to establish a local facies model quickly and accurately, and play a role in facies studying, to eliminate some artificial influnce, and to favor the dialogue between geologists, in this paper authors used the Markov chain to determine vertical relationship of the sedimentary sequence of the Linpan delta and the Shanghe deep-water turbidite fan and to establish the local facies models. Practice has indicated that the Markov chain is an effective method to establish local facies model, and it is suitable for rhythmical complex stratigraphic sequence. The steps of Markov chain established facies modle are following: 1. Observe stratigraphic section carefully, based on a varity of facies marks, determine facies with different characteristics and their relationship plotted relation diagram of facies change; 2. Count the whole number of facies changes and the number of facies changes from one into another, establish the matrix of facies change number, determine facies change probability of sequence; observed 3. Fix the facies change probability of random sequence; 4. Determine the diffe- rence of facies change probability between the observed and random sequences,
1987, 5(4): 115-126.
Abstract:
The terrestrial crude oil of China contains nickel porphyrin but none vanadyl porphyrin, detected by UVS ESR and elements analysis. In 11 basins, such as Junggar., Qaidam, Jianghan, Songliao etc., the Ni-porphyrin content in Cainozoic crude oil is higher than that in Mesozoic. Ni-porphyrin content has not obvious relation to the increase and decrease of resines, asphaltenes and sulfurs. But if the crude oil was occured from saline lake-basin the content of Ni-porphyrin would be higher. The vanadyl-porphyrin is mostly distributed in the factions of non-hydrocarbons and asphaltenes of the crude oil. The Ni-porphyrin is mainly distributed in alomatic fraction, but less in the fraction, of non-hydrocarbons. In the crude oil of hypergene-oxidized zone, the vanadyl porphyrin trends to increase, but Ni-porphyrin does not. In catagenesis stage of the crude oil, the thermal stability of Ni-porphyrin is lower than that of vanadyl porphyrin(the velocity of thermal degradation of Ni-porphyrin is faster than that of vanadyl porphyrin). The Ni-porphyrin is higher in low-maturity crude oil and lower in mid-maturity crude oil, but none in high-maturity crude oil and condensate. During the conversion of organic materials into oil-gas the time of Ni-porphyrin formed is earlier than a large quantity of hydrocarbons formed. With the increase of depth, the kerogen can convert into hydrocarbons by the thermal degradation, but it can't generate Ni-porphyrin, contrariwise, with the increase of temperature its content gradually disapears from decrease because of the characters of its thermal stability. Without doubt, the texture of Ni-porphyrin also occurs some changes correspondly. Therefore, Ni-porphyrins of crude oil were derived from the pigments of original organic materials during the stage of diagenesis.
The terrestrial crude oil of China contains nickel porphyrin but none vanadyl porphyrin, detected by UVS ESR and elements analysis. In 11 basins, such as Junggar., Qaidam, Jianghan, Songliao etc., the Ni-porphyrin content in Cainozoic crude oil is higher than that in Mesozoic. Ni-porphyrin content has not obvious relation to the increase and decrease of resines, asphaltenes and sulfurs. But if the crude oil was occured from saline lake-basin the content of Ni-porphyrin would be higher. The vanadyl-porphyrin is mostly distributed in the factions of non-hydrocarbons and asphaltenes of the crude oil. The Ni-porphyrin is mainly distributed in alomatic fraction, but less in the fraction, of non-hydrocarbons. In the crude oil of hypergene-oxidized zone, the vanadyl porphyrin trends to increase, but Ni-porphyrin does not. In catagenesis stage of the crude oil, the thermal stability of Ni-porphyrin is lower than that of vanadyl porphyrin(the velocity of thermal degradation of Ni-porphyrin is faster than that of vanadyl porphyrin). The Ni-porphyrin is higher in low-maturity crude oil and lower in mid-maturity crude oil, but none in high-maturity crude oil and condensate. During the conversion of organic materials into oil-gas the time of Ni-porphyrin formed is earlier than a large quantity of hydrocarbons formed. With the increase of depth, the kerogen can convert into hydrocarbons by the thermal degradation, but it can't generate Ni-porphyrin, contrariwise, with the increase of temperature its content gradually disapears from decrease because of the characters of its thermal stability. Without doubt, the texture of Ni-porphyrin also occurs some changes correspondly. Therefore, Ni-porphyrins of crude oil were derived from the pigments of original organic materials during the stage of diagenesis.
1987, 5(4): 147-158.
Abstract:
In recent years, the marine palynology has been used to study the movement and distribution of marine sediments. Spore-pollen as a part of the marine sediments moves with mud and sand, and it has a unique form owing to originating from plants, so it can offer more and clear information on sedimentary environments. Based on the study of the spore-pollen assemblage of surface samples from the radial sandy ridges along the coast of Northern Jiangsu Province during 1980-1981, the author found that the spore-pollen was a good index to reflect the hydrodynamics, material origin and the material distribution of the sandy ridge groups. Meanwhile, it was the medium to study the relationship between marine sediments and the dynamics of sea water. So the study on the recent developing process of the radial sandy ridges could be promoted by using the spore-pollen analysis. The radial sandy ridges of the shore of Northern Jiangsu Province are distributed between the estuary of the Changjiang River(Yangtze) and that of the old Huanghe River(Yellow River). These two rivers influenced the spore-pollen assemblage of this area and its variation. The spore-pollen assemblage in the estuary of the Changjiang River is a Pinus-Pteridium-Polypodiaceae-Quercus assemblage, while in the estuary of the old Huanghe River is a Pinus-Pteridium-Artemisia-Chenopodiaceae assemblage. The spore-pollen assemblage in the main body of the radial sandy ridges is a Pinus-Compostae-Pteridium-Artemisia assemblage. The spore-pollen analysis of the area shows that the spread range of the Changjiang dalta sediments, indicated by aquatic plants, pollens and algae, is at 122?0'E and at 32°20'N, but the pollens of aquatic plants and algae from the old Huanghe River are only distributed in the old Huanghe dalta. The distribution of Pinus-pollen is closely related to the dynamics of sea-water, the content of Pinus-pollen is lower in the region of turblent flow but higher in quiet waters. The concentration and the preservative state of spore-pollen are the important index to judge the type, distribution and age of sediments. The region with high concentration of spore-pollen is a fine-grained sediment region. The region with low concentration is generally a coarse fine sand region. The region where the spore-pollen is in fair preservation is the region with weaker dynamics and younger sediments, and the region where spore-pollen is in poor preservation is the region with stronger dynamics and older sediments. The main part of the radial sandy ridges could be formed during the late Pleistocene Wurm glaciation and reworked by recent tidal current.
In recent years, the marine palynology has been used to study the movement and distribution of marine sediments. Spore-pollen as a part of the marine sediments moves with mud and sand, and it has a unique form owing to originating from plants, so it can offer more and clear information on sedimentary environments. Based on the study of the spore-pollen assemblage of surface samples from the radial sandy ridges along the coast of Northern Jiangsu Province during 1980-1981, the author found that the spore-pollen was a good index to reflect the hydrodynamics, material origin and the material distribution of the sandy ridge groups. Meanwhile, it was the medium to study the relationship between marine sediments and the dynamics of sea water. So the study on the recent developing process of the radial sandy ridges could be promoted by using the spore-pollen analysis. The radial sandy ridges of the shore of Northern Jiangsu Province are distributed between the estuary of the Changjiang River(Yangtze) and that of the old Huanghe River(Yellow River). These two rivers influenced the spore-pollen assemblage of this area and its variation. The spore-pollen assemblage in the estuary of the Changjiang River is a Pinus-Pteridium-Polypodiaceae-Quercus assemblage, while in the estuary of the old Huanghe River is a Pinus-Pteridium-Artemisia-Chenopodiaceae assemblage. The spore-pollen assemblage in the main body of the radial sandy ridges is a Pinus-Compostae-Pteridium-Artemisia assemblage. The spore-pollen analysis of the area shows that the spread range of the Changjiang dalta sediments, indicated by aquatic plants, pollens and algae, is at 122?0'E and at 32°20'N, but the pollens of aquatic plants and algae from the old Huanghe River are only distributed in the old Huanghe dalta. The distribution of Pinus-pollen is closely related to the dynamics of sea-water, the content of Pinus-pollen is lower in the region of turblent flow but higher in quiet waters. The concentration and the preservative state of spore-pollen are the important index to judge the type, distribution and age of sediments. The region with high concentration of spore-pollen is a fine-grained sediment region. The region with low concentration is generally a coarse fine sand region. The region where the spore-pollen is in fair preservation is the region with weaker dynamics and younger sediments, and the region where spore-pollen is in poor preservation is the region with stronger dynamics and older sediments. The main part of the radial sandy ridges could be formed during the late Pleistocene Wurm glaciation and reworked by recent tidal current.
