1993 Vol. 11, No. 4
column
Display Method:
1993, 11(4): 1-7.
Abstract:
In present paper the distribution of ore - forming material and ore - forming background before forming of uranium deposits is South China are reviewed according to the forming and classification of uraniferous de-positional formations in this area. Author firstly proposes the three kinds of uraniferous depositional formation in South China, i.e. the uraniferous formation (I) of geosynclinal - type terrigenous fragment -volcanic deposit in Sinian -Cambrian periods, the uraniferous formation (II) of platform -type terrigenous fragmental deposit in Palaeozoic Era and the uraniferous formation (III) of platform - type terrigenous fragment - volcanic deposit in Mesozoic - Cenozoic Era. Most of uranium deposits in South China were controlled by those uraniferous depositional formations in space. Finally, author generalizes the principal features of uraniferous depositional formations and genetic relationship between all kinds of uranium deposits and various uraniferous depositional formations in South China. The most important features of uraniferous depositional formations include: (1) It is composed of uraniferous strata as well as non-uranlferous strata; (2) Uranium abundance in it is higher than that in the earth crust, in general several times or tens times; (3) It is rich in organic material, pyrite, carbonaceous - pelite and phosphate etc. which could intensely adsorb and reduce uranium ( VI ) ; (4) In rocks uranium element unevenly distributes, often in the condition of multipeak; (5) Uranium element mainly is in the form of adsorption in rocks; (6) Uranium -rich strata relatively are rich in elements of P. Mo, Ni, V, Zn, Cu, Pb, Ag etc. . Among three formations the uraniferous formation of geosynclinal -type terrigenous fragment -volcanic deposit in Sinian - Cambrian periods (I) is the most important for forming of uranium deposits in South China. The geosynclinal-type depositional formations in Proterozoic Era are the ancient (maybe the most ancient) uraniferous strata in South China.
In present paper the distribution of ore - forming material and ore - forming background before forming of uranium deposits is South China are reviewed according to the forming and classification of uraniferous de-positional formations in this area. Author firstly proposes the three kinds of uraniferous depositional formation in South China, i.e. the uraniferous formation (I) of geosynclinal - type terrigenous fragment -volcanic deposit in Sinian -Cambrian periods, the uraniferous formation (II) of platform -type terrigenous fragmental deposit in Palaeozoic Era and the uraniferous formation (III) of platform - type terrigenous fragment - volcanic deposit in Mesozoic - Cenozoic Era. Most of uranium deposits in South China were controlled by those uraniferous depositional formations in space. Finally, author generalizes the principal features of uraniferous depositional formations and genetic relationship between all kinds of uranium deposits and various uraniferous depositional formations in South China. The most important features of uraniferous depositional formations include: (1) It is composed of uraniferous strata as well as non-uranlferous strata; (2) Uranium abundance in it is higher than that in the earth crust, in general several times or tens times; (3) It is rich in organic material, pyrite, carbonaceous - pelite and phosphate etc. which could intensely adsorb and reduce uranium ( VI ) ; (4) In rocks uranium element unevenly distributes, often in the condition of multipeak; (5) Uranium element mainly is in the form of adsorption in rocks; (6) Uranium -rich strata relatively are rich in elements of P. Mo, Ni, V, Zn, Cu, Pb, Ag etc. . Among three formations the uraniferous formation of geosynclinal -type terrigenous fragment -volcanic deposit in Sinian - Cambrian periods (I) is the most important for forming of uranium deposits in South China. The geosynclinal-type depositional formations in Proterozoic Era are the ancient (maybe the most ancient) uraniferous strata in South China.
1993, 11(4): 17-23.
Abstract:
Through analysing the sedimentary rock system and the structural deformation, this article thinks Keipin uplift belongs to the north of Talimu craton. The major porpress of it's sediment evolution and structure evdution are identical with those of Talimu Massif. There are two major kinds of sedimentary rock system in the Keipin uplift; One of them is the steady platform facies sediment. The other is mainly made up of the cenozoic sediment, including salt seashore-legoon facies sediment, river facies and hillfoot facies. The Keipin uplift is the sturctural deformation which was set of by the gravity spreading, effect carsed by the south Tahshan thrust folded rising under the steady craton circumstance in the late Hereynian.
Through analysing the sedimentary rock system and the structural deformation, this article thinks Keipin uplift belongs to the north of Talimu craton. The major porpress of it's sediment evolution and structure evdution are identical with those of Talimu Massif. There are two major kinds of sedimentary rock system in the Keipin uplift; One of them is the steady platform facies sediment. The other is mainly made up of the cenozoic sediment, including salt seashore-legoon facies sediment, river facies and hillfoot facies. The Keipin uplift is the sturctural deformation which was set of by the gravity spreading, effect carsed by the south Tahshan thrust folded rising under the steady craton circumstance in the late Hereynian.
1993, 11(4): 30-36.
Abstract:
It grows a group of the autochthonous storm deposits in the Wumishan formation of the middle - late Proterozoic in the Jixian area. The complete depositional sequence character is: the bottom unit is the silex striped fine - powdery graded dolomitite. The lower unit A has two types, one is the autochthonous storm-fringe deposits, it's the silex striped dolomitite and fine graded dolomitite, there is a hummocky stirring bedding in the strate, the other is the autochthonous storm-center deposits, it's hummpcky breccia, the tabular breccias of silex and dolomitite show vertical fan, radiating, sheaf, radiator arrangement in the section and triangle trellis arrangement on the surface. The middle unit B is the white and black streaking powery -fine graded dolomitite with corrugated bedding. The upper unit C is the silex striped asphaltic fine graded dolorm-lite with horizontal bedding. The top unit D is the silex striped stromatolites dolomitite with thick -massive bedding. The uncomplete depositional sequence is: the unit B or C often absent, only it's the A that is a mark to identify the autochthonous storm deposits. During the deposition of the Wumishan formation of the middle -late Proterozoic, the platform of the Jixian area was in Pacific Ocean, the palaeolatitude was 1°-10°N, the depth of seawater was less in the basin. The sedimentary environment was shallow sea. It was the same as the area of 5°-20°N latitude of the modern storm movement. There must were storm moving here during the Wumishan formation. A strong vortices storm whirled the seawater highly during the storm event. The strom wave base was deepened to get to 200m depth, the seabed geted huge shearing stress U which can be resloved into horizontal U1 and vertical U2. When weak storm, U2 was a little force which couldn't cut out anything on the seabed, U1 pulled the sediments of seabed to go to vortes point, hummocky stirring bedding was shapeed. This is the autochthonous storm -fringe deposits. When stron storm, U1 pulled and U2 cut off the carbonate sediments on seabed. Breccia was shaped. Under the vortices flows action, breccias were moving to vortex center. At last, breccias showed vertical fan, radiating, sheaf, radkator arrangement in the section and triangle trellis arrangement on the surface. This is the autochthonous storm -cneter deposits. In late storm, the seawater flows turned the upper flow regime vortex into the lower flow regime. The coarse grade loose carbonate sediments were confused by storm and redeposited to make corrgated bedding, and the fine graded redeposited to get horizontal bedding in the lower flow regime of storm end. In fair weather, the fine sun. prosperous organisms, rich sediments, the thick-massive was made. There weren't the tsunami during the deposition of the Wumishan formation, because the mark of the earthquake and the vulcenicity has been not discovered in the strata of the Wumishan formation. There only is the autochthonous storm deposits cf storm direct action, it's different from the storm gravity flows and the pattern showing autochlonstorm sedimentary on ramp.
It grows a group of the autochthonous storm deposits in the Wumishan formation of the middle - late Proterozoic in the Jixian area. The complete depositional sequence character is: the bottom unit is the silex striped fine - powdery graded dolomitite. The lower unit A has two types, one is the autochthonous storm-fringe deposits, it's the silex striped dolomitite and fine graded dolomitite, there is a hummocky stirring bedding in the strate, the other is the autochthonous storm-center deposits, it's hummpcky breccia, the tabular breccias of silex and dolomitite show vertical fan, radiating, sheaf, radiator arrangement in the section and triangle trellis arrangement on the surface. The middle unit B is the white and black streaking powery -fine graded dolomitite with corrugated bedding. The upper unit C is the silex striped asphaltic fine graded dolorm-lite with horizontal bedding. The top unit D is the silex striped stromatolites dolomitite with thick -massive bedding. The uncomplete depositional sequence is: the unit B or C often absent, only it's the A that is a mark to identify the autochthonous storm deposits. During the deposition of the Wumishan formation of the middle -late Proterozoic, the platform of the Jixian area was in Pacific Ocean, the palaeolatitude was 1°-10°N, the depth of seawater was less in the basin. The sedimentary environment was shallow sea. It was the same as the area of 5°-20°N latitude of the modern storm movement. There must were storm moving here during the Wumishan formation. A strong vortices storm whirled the seawater highly during the storm event. The strom wave base was deepened to get to 200m depth, the seabed geted huge shearing stress U which can be resloved into horizontal U1 and vertical U2. When weak storm, U2 was a little force which couldn't cut out anything on the seabed, U1 pulled the sediments of seabed to go to vortes point, hummocky stirring bedding was shapeed. This is the autochthonous storm -fringe deposits. When stron storm, U1 pulled and U2 cut off the carbonate sediments on seabed. Breccia was shaped. Under the vortices flows action, breccias were moving to vortex center. At last, breccias showed vertical fan, radiating, sheaf, radkator arrangement in the section and triangle trellis arrangement on the surface. This is the autochthonous storm -cneter deposits. In late storm, the seawater flows turned the upper flow regime vortex into the lower flow regime. The coarse grade loose carbonate sediments were confused by storm and redeposited to make corrgated bedding, and the fine graded redeposited to get horizontal bedding in the lower flow regime of storm end. In fair weather, the fine sun. prosperous organisms, rich sediments, the thick-massive was made. There weren't the tsunami during the deposition of the Wumishan formation, because the mark of the earthquake and the vulcenicity has been not discovered in the strata of the Wumishan formation. There only is the autochthonous storm deposits cf storm direct action, it's different from the storm gravity flows and the pattern showing autochlonstorm sedimentary on ramp.
1993, 11(4): 47-55.
Abstract:
This paper outlines the Jiangnan Carbonate platform of early Triassic (in brief, Which is called the plat-form fellow) by some cr:,parite beaches of high energy, and through the comparation of the longitudinal sec-tion with latitudinal action of the oosparite limestone, We have discovered the ooide beach migrated regular-1y in history and spaces. A large amount of various olistostrome structures and products of slumping such asslump breccia,nodular limestone are discovered in the deposits of both north and south sided of the Plat-for m,thus confirrn two .slope zone existed on the two sides of the platform. The slope zones are contiguousoutward to the zone cf wlf facies,b:,sin fades in turn. "rl:e slop zone in the onrth-west platform is bread,which distribute an extensive area in South Jiangsu and South Anhui according to the specialities of petrolo-gY .the sequences of sections :end palaeontology,we can distinguish two types of slopes:the frontier slop ofthe plafotm (the u):per slopel and the marginal slope of the shelf (the lower slope),it is verified by data thatthis two slopes have migrated in history and spaces. The slope zone in the south-east plaform is bounded bya contemporaneous normal fault,which adjacent to the Lianhua-Qiansan deep turbidite basin,it's lack of fa-cies variety- rnay relate to the later structural modificatiun. This cone is also a Loundary between the elasticrocks and carbonate rocks of early Triassic in South China. The early Triassic of Lower YanKtze region is of Significent source rocks regicnally, and facies distributefrom platform to basin in a good order,from south-east to north-west,they appear as:platform-themarginal oxide beach of the Platform-slop-shelf-basin in turn. The deep shelf and basins have yielded oil/gas,which have migiated and been trapped in the near :.lope zone and marginal ooic?e beach,forming a finematch of source rock and reservoir. The extensive marginal oxide beach in the north-west margin of theJiangnan plaform is fine oil/gas reservoir,besides,studiying dueply, -we have found extensive nocdulas lime-stone in slop/one that is a new reservoir type,and oil seepsges have been found already-. But,the structures of this region were modified strongly in the later,it is a decisive factor for oil/gas control. This area has ex-perienced two large scale sturctural activities after later Triassic: the compressional activity from later Trias-sic to early Cretaceous:the stretching and fault depressional activity after Cretaceous. These activities haveboth constructive and destructive contribution for accumulation of oil and gas.The conclusion is that the marginal ooide beach and slope zone in the north-east Jiangnan Platform arethe best favourable area for oil/gas exploration in this region. Because covered thickly by later Triassic-Jurassic,the source rocks of the shelf basin and a part of slope zone of lower Triassic have partly matured,it's products have migrated and been trapped by the slope zone. The data of the thermal history of regionallayers verified that,only in the fault basins that are covered by Cretaceous-Tertiary thicker than 1,500m,could the source rocks of lower Triassic completely enter into peak generation of hydrocarbone,they migrat-ed to the stractural traps existed before. So that,along Nanjing-Nantong,the region located at the centreposition of thrust faults and folds that have the features of base decapple and cover layer detachment in thenorth-east direction owing to the compressional activities of later Triassic-early Cretaceous,has been mod-ified weakerly and has been covered not only by deposits but also by nappies,the source rocks have maturedalready, and it's products have migrated laterally,so this region is prospective for oil/gas exploration.
This paper outlines the Jiangnan Carbonate platform of early Triassic (in brief, Which is called the plat-form fellow) by some cr:,parite beaches of high energy, and through the comparation of the longitudinal sec-tion with latitudinal action of the oosparite limestone, We have discovered the ooide beach migrated regular-1y in history and spaces. A large amount of various olistostrome structures and products of slumping such asslump breccia,nodular limestone are discovered in the deposits of both north and south sided of the Plat-for m,thus confirrn two .slope zone existed on the two sides of the platform. The slope zones are contiguousoutward to the zone cf wlf facies,b:,sin fades in turn. "rl:e slop zone in the onrth-west platform is bread,which distribute an extensive area in South Jiangsu and South Anhui according to the specialities of petrolo-gY .the sequences of sections :end palaeontology,we can distinguish two types of slopes:the frontier slop ofthe plafotm (the u):per slopel and the marginal slope of the shelf (the lower slope),it is verified by data thatthis two slopes have migrated in history and spaces. The slope zone in the south-east plaform is bounded bya contemporaneous normal fault,which adjacent to the Lianhua-Qiansan deep turbidite basin,it's lack of fa-cies variety- rnay relate to the later structural modificatiun. This cone is also a Loundary between the elasticrocks and carbonate rocks of early Triassic in South China. The early Triassic of Lower YanKtze region is of Significent source rocks regicnally, and facies distributefrom platform to basin in a good order,from south-east to north-west,they appear as:platform-themarginal oxide beach of the Platform-slop-shelf-basin in turn. The deep shelf and basins have yielded oil/gas,which have migiated and been trapped in the near :.lope zone and marginal ooic?e beach,forming a finematch of source rock and reservoir. The extensive marginal oxide beach in the north-west margin of theJiangnan plaform is fine oil/gas reservoir,besides,studiying dueply, -we have found extensive nocdulas lime-stone in slop/one that is a new reservoir type,and oil seepsges have been found already-. But,the structures of this region were modified strongly in the later,it is a decisive factor for oil/gas control. This area has ex-perienced two large scale sturctural activities after later Triassic: the compressional activity from later Trias-sic to early Cretaceous:the stretching and fault depressional activity after Cretaceous. These activities haveboth constructive and destructive contribution for accumulation of oil and gas.The conclusion is that the marginal ooide beach and slope zone in the north-east Jiangnan Platform arethe best favourable area for oil/gas exploration in this region. Because covered thickly by later Triassic-Jurassic,the source rocks of the shelf basin and a part of slope zone of lower Triassic have partly matured,it's products have migrated and been trapped by the slope zone. The data of the thermal history of regionallayers verified that,only in the fault basins that are covered by Cretaceous-Tertiary thicker than 1,500m,could the source rocks of lower Triassic completely enter into peak generation of hydrocarbone,they migrat-ed to the stractural traps existed before. So that,along Nanjing-Nantong,the region located at the centreposition of thrust faults and folds that have the features of base decapple and cover layer detachment in thenorth-east direction owing to the compressional activities of later Triassic-early Cretaceous,has been mod-ified weakerly and has been covered not only by deposits but also by nappies,the source rocks have maturedalready, and it's products have migrated laterally,so this region is prospective for oil/gas exploration.
1993, 11(4): 67-72.
Abstract:
Ther are only Lower and Middle Ordovician in Xiangfen district. which are mainly composed of carbonate rocks and evaporites. The siliceous and clastic rocks are very little. The carbonate rocks include limestones and dolostones. According to origin and texture, carbonate rocks are divided into grain limestone, lime -mud limestone, finely crystalline limeston. dolomite - mottled limestone, gypsum - dissolved breccia limestone, mud - sued crystalline dolostone. mudy mud - slit --sized crystalline dolostone. finely - comsely crystalline dolostone. Detailed description and genetic analysis in the paper are made for the main rock types. Mud - silt - sized crystalline dolostone is commonly associated with gypsum. This dolomite resulted from supratidal (gypsum) dolomite flats or gypsum lagoons by peneconternporaneous evaporative pumping. Coarse - grained dolomite were mainly formed in post - ponecontemppraneous mixed waters and seepage reflux dolomitization. In Liangjiashan Formation of Lower Ordovician (O1) , siliceous rocks (chert) are found accompanying with post - penecontemporaneous dolostones. They occur as lumps, nodules and ribbons. The study shows they resulted from silicification, which was later than dolomitization. There are laminated, massive and brecciated gypsum, formed by evaporation and by dissolution. The stable isotope data indicates that the average δ18O value of carbonate rocks is -5. 832‰ (PDB), showing a great influence of meteoric waters on them. The average δ18C value is -1. 210‰ (PDB), varying in a narrow range. The Z value indicating paleosalinity is usually bigger than 120. It snows that most of carbonate rocks were deposited in marine environments, but influenced by meteoric waters. The Fe/Mn value of carbonate rocks varies from 22. 3 to 47. 3. Sr/Ba value varies from 0. 50 to 1. 21, but most of them are less than 1, showing a near- continental sedimentation and an intense meteoric water influence on the carbonate rocks. On the basis of the study of petrology and fades indicators, sedimentary environments of every formation (5 in all) are analysed. It shows that Xiangfen area in Ordovician experienced two wide -spread regressions (in the late Early Ordovician and late Middle Ordovician ) and a wide -spread transgression (in the early Middle Ordovician). The sedimentary environments were mainly supratidal flats (including gypsum lagoons), intertidal zones, subtidal restricted seas and open seas. The largest regression in late Middle Ordovician after Fengfeng Stage ended the marine sedimentary history of Xiangfen area in Ordovician.
Ther are only Lower and Middle Ordovician in Xiangfen district. which are mainly composed of carbonate rocks and evaporites. The siliceous and clastic rocks are very little. The carbonate rocks include limestones and dolostones. According to origin and texture, carbonate rocks are divided into grain limestone, lime -mud limestone, finely crystalline limeston. dolomite - mottled limestone, gypsum - dissolved breccia limestone, mud - sued crystalline dolostone. mudy mud - slit --sized crystalline dolostone. finely - comsely crystalline dolostone. Detailed description and genetic analysis in the paper are made for the main rock types. Mud - silt - sized crystalline dolostone is commonly associated with gypsum. This dolomite resulted from supratidal (gypsum) dolomite flats or gypsum lagoons by peneconternporaneous evaporative pumping. Coarse - grained dolomite were mainly formed in post - ponecontemppraneous mixed waters and seepage reflux dolomitization. In Liangjiashan Formation of Lower Ordovician (O1) , siliceous rocks (chert) are found accompanying with post - penecontemporaneous dolostones. They occur as lumps, nodules and ribbons. The study shows they resulted from silicification, which was later than dolomitization. There are laminated, massive and brecciated gypsum, formed by evaporation and by dissolution. The stable isotope data indicates that the average δ18O value of carbonate rocks is -5. 832‰ (PDB), showing a great influence of meteoric waters on them. The average δ18C value is -1. 210‰ (PDB), varying in a narrow range. The Z value indicating paleosalinity is usually bigger than 120. It snows that most of carbonate rocks were deposited in marine environments, but influenced by meteoric waters. The Fe/Mn value of carbonate rocks varies from 22. 3 to 47. 3. Sr/Ba value varies from 0. 50 to 1. 21, but most of them are less than 1, showing a near- continental sedimentation and an intense meteoric water influence on the carbonate rocks. On the basis of the study of petrology and fades indicators, sedimentary environments of every formation (5 in all) are analysed. It shows that Xiangfen area in Ordovician experienced two wide -spread regressions (in the late Early Ordovician and late Middle Ordovician ) and a wide -spread transgression (in the early Middle Ordovician). The sedimentary environments were mainly supratidal flats (including gypsum lagoons), intertidal zones, subtidal restricted seas and open seas. The largest regression in late Middle Ordovician after Fengfeng Stage ended the marine sedimentary history of Xiangfen area in Ordovician.
1993, 11(4): 85-91.
Abstract:
The pyrite deposits of the Southwest sulfide zone mainly develop at the bottom of the Permian Longtancoal-series,whivh to a certain extent,has velation with the eruption of the Emeishon Basalt. Investigationsof dcposits by the author paint out some biotrxture-marked pyrites and framF,oidal pyrites. Under SEM andEPA examinations,frambeidal aggcregate of pylite. enolosed within organisms is proved as a kind of from-boidal b.ma}ri.i while t,iotextures of pyrite are causcd by replacemrnt. On the basis of the above studies,theauthor, descrihes a close corrvelation betwcen the biotexturrs and the formation of the framboidal pyrite. Tospeak in detail,when basaltic erupted,flcwrd and reached sea basin, it decomposed right away in the pees-ence of sea water and separated into a great number of ferrugincus materials. These linked befwe long withthe H2S produced through,reduction of sulfate and deconnposition, of ogranic sulfur,all,by bacterium.finally to form pyrite. In the course of later sedirnento-disgenesis,franrboidal sulfur bacteriom were adle to highly brced within buried organisms. In the meantime?if there existed a strongly reducing regime around the microorganisms,the S。 of their bodies would react with the nearby Fe2+HS- and FeS. This led not only ti.precipitation of framboidal pyrites also to perfect preservation of the biotextures which featured them. From the above explanation,one can easily concludes that the pyrite of the study area its mineralizationto the ferruginous influx related to decomposition of basalt by sea water and,what is more important,to ac-tivities of microorganisms and bacterium:one directly having a band in sulfur production and the other beingresponsible for sulfate reduction and,indirectly, for sulfur mineralization.
The pyrite deposits of the Southwest sulfide zone mainly develop at the bottom of the Permian Longtancoal-series,whivh to a certain extent,has velation with the eruption of the Emeishon Basalt. Investigationsof dcposits by the author paint out some biotrxture-marked pyrites and framF,oidal pyrites. Under SEM andEPA examinations,frambeidal aggcregate of pylite. enolosed within organisms is proved as a kind of from-boidal b.ma}ri.i while t,iotextures of pyrite are causcd by replacemrnt. On the basis of the above studies,theauthor, descrihes a close corrvelation betwcen the biotexturrs and the formation of the framboidal pyrite. Tospeak in detail,when basaltic erupted,flcwrd and reached sea basin, it decomposed right away in the pees-ence of sea water and separated into a great number of ferrugincus materials. These linked befwe long withthe H2S produced through,reduction of sulfate and deconnposition, of ogranic sulfur,all,by bacterium.finally to form pyrite. In the course of later sedirnento-disgenesis,franrboidal sulfur bacteriom were adle to highly brced within buried organisms. In the meantime?if there existed a strongly reducing regime around the microorganisms,the S。 of their bodies would react with the nearby Fe2+HS- and FeS. This led not only ti.precipitation of framboidal pyrites also to perfect preservation of the biotextures which featured them. From the above explanation,one can easily concludes that the pyrite of the study area its mineralizationto the ferruginous influx related to decomposition of basalt by sea water and,what is more important,to ac-tivities of microorganisms and bacterium:one directly having a band in sulfur production and the other beingresponsible for sulfate reduction and,indirectly, for sulfur mineralization.
1993, 11(4): 99-104.
Abstract:
As we research argillaceous sediments containing some interstratified clay minerals by the method of XRD quantitative analysis, the first parameter that needs to determinate is the proportion (f) of two component layers. Theoretically, we led to an approximate functional relationship between the proportions (f) and the observed XRD layer spaces (d) of randomly interstratified clay minerals. Therefor we made out a d -f contrasting table for illite/montmorillonite. The intensity parameter K of one mineral is the fundamental parameter for XRD quantitative analysis. Generally, researchers can't separate single clay mineral from argillaceous sediments. In this case, by a special way, we obtained the K values of clay minerals in Jiyang basin. The method of XRD quantitative analysis for argillaceous sediments have applied to hundreds of samples successfully. For the natural oriented section, we can more accurately obtain the relative contents of six minerals, including montmorillonite, I/S interlayer, clastic illite, kaolinite, chlorite and muscovite. For the random powder sample, we can obtain the relative contents of ten minerals, including quartz, feldspar, cal-cite and dolomite except for the six ones listed above. Only one diffraction profile of natural sample is necessary.
As we research argillaceous sediments containing some interstratified clay minerals by the method of XRD quantitative analysis, the first parameter that needs to determinate is the proportion (f) of two component layers. Theoretically, we led to an approximate functional relationship between the proportions (f) and the observed XRD layer spaces (d) of randomly interstratified clay minerals. Therefor we made out a d -f contrasting table for illite/montmorillonite. The intensity parameter K of one mineral is the fundamental parameter for XRD quantitative analysis. Generally, researchers can't separate single clay mineral from argillaceous sediments. In this case, by a special way, we obtained the K values of clay minerals in Jiyang basin. The method of XRD quantitative analysis for argillaceous sediments have applied to hundreds of samples successfully. For the natural oriented section, we can more accurately obtain the relative contents of six minerals, including montmorillonite, I/S interlayer, clastic illite, kaolinite, chlorite and muscovite. For the random powder sample, we can obtain the relative contents of ten minerals, including quartz, feldspar, cal-cite and dolomite except for the six ones listed above. Only one diffraction profile of natural sample is necessary.
1993, 11(4): 8-16.
Abstract:
The Xingshenbao phosphorus deposits locates in the westein Hubei Province and phosphorite is presented in the middle and lowar Doushantuo Formation of Sinisn System. Thickness of the rock series bearing phosphorus is 12. 4 -473.5m and the rock series bearing phosphoras consisis of dolomite bearing manganese, botia, mud stctie, phosphorite and dolomite. The phospholite thickness is 1. 9-17. 6m and the average content of P2O5 is 22. 80%. According to saditagry sheractaristics of the cook series bearing phosphorus is divided into three region of sedimentary facies. They are shallew besin facics in Wawu, lagoon facies in Zhengjiahe and tidal flatfacies in the Tangzhaying. The industrial phosphorites scdirnented in the shallow basin and lagoon and consists of comular spharolth , alga and bacteria granula , shelly granula and stromatolite etc. . which have been produced by organisnis and biochemical activity as have been accumulted in the orginal phace. It is controled that origin of phosphorus and organisms activity, therefore only forms lean min-earls or does't form mineral in the tidal. The Tangzhaying - Paiguoping palaeo-rise controls the time and space distribution of phosphorite in region. Researches of petrology and geochemistry indicate there is a lagoon circumstance with hypersaline during the early period of the rock series bearing phosphorus and the tidal flat circumstance in the late period, which is affected by the leaching action of fresh water. During the early period for the formation of phosphorite are the shallow basin and lagoen with the lower energy, which forms algal met phosphorite, algal and bacteria one and pelletal one. During the late period for the formation of phosphorite are algal hill and bank, which forms stromatolithic phosphorite and slelly granule one. The firsh phosphorus ore bed (Ph1) sedimented in reducing circcnstance and the second one (Ph1) in week oxidation. The rock series bearing phosphorus is a regression sedimenting scquece under whole transgre-sion condition.
The Xingshenbao phosphorus deposits locates in the westein Hubei Province and phosphorite is presented in the middle and lowar Doushantuo Formation of Sinisn System. Thickness of the rock series bearing phosphorus is 12. 4 -473.5m and the rock series bearing phosphoras consisis of dolomite bearing manganese, botia, mud stctie, phosphorite and dolomite. The phospholite thickness is 1. 9-17. 6m and the average content of P2O5 is 22. 80%. According to saditagry sheractaristics of the cook series bearing phosphorus is divided into three region of sedimentary facies. They are shallew besin facics in Wawu, lagoon facies in Zhengjiahe and tidal flatfacies in the Tangzhaying. The industrial phosphorites scdirnented in the shallow basin and lagoon and consists of comular spharolth , alga and bacteria granula , shelly granula and stromatolite etc. . which have been produced by organisnis and biochemical activity as have been accumulted in the orginal phace. It is controled that origin of phosphorus and organisms activity, therefore only forms lean min-earls or does't form mineral in the tidal. The Tangzhaying - Paiguoping palaeo-rise controls the time and space distribution of phosphorite in region. Researches of petrology and geochemistry indicate there is a lagoon circumstance with hypersaline during the early period of the rock series bearing phosphorus and the tidal flat circumstance in the late period, which is affected by the leaching action of fresh water. During the early period for the formation of phosphorite are the shallow basin and lagoen with the lower energy, which forms algal met phosphorite, algal and bacteria one and pelletal one. During the late period for the formation of phosphorite are algal hill and bank, which forms stromatolithic phosphorite and slelly granule one. The firsh phosphorus ore bed (Ph1) sedimented in reducing circcnstance and the second one (Ph1) in week oxidation. The rock series bearing phosphorus is a regression sedimenting scquece under whole transgre-sion condition.
1993, 11(4): 24-29.
Abstract:
By using the method of modern sedimentology analysis to study carbonate and terrigenous clastic sediments of the Early and Middle Triassic in South and Central Guizhou, sedimentary sequences and mechanism made those sequences of this area are discussed. In the paper, sediment characteristics and sedimentary sequences, petrologic assemblage of carbonate platform, slope and basin facies is discussed individually, the carbonate platform deposited dolote, bird's-eye, secondary pore dolomite, dolomite breccia and banded limestone. The slope belt developed gravity flow and turbidite, essential petrologic assemblage for thin limestones and limestone breccia, low density turidite and deep wate marls or mudstones occurred in the basin. Sequence stratigraphy of Lower and Middle Triassic in the area is studied in the paper and the paper emphasised in sequence stratigraphy and sea levle changes, two types of sequence boundaries were identified, i.e. , Type I, Indian -Olenekian and Olenekian -Anisian. Type II, Permian -Indian, there are two type II sequence boundaris in the Olenekian, contemporaneously, each depositional sequence composed of lowstand systems tract, transgressive systems tract and highstand systems tract, and lowstand, hightand and transgressive systems tract of each depositional sequence are discussed on petrologic assemblage. According to the relationship between the systems tract and sea level changes, the curves showing the sea level changes in Southern and Central Guizhou during Early and Middle Triassic are also established by the author in this paper, and worker suggest that sedimentary characteristics on carbonate platform, slope and basin be controlled by sea level changing and structual porcess.
By using the method of modern sedimentology analysis to study carbonate and terrigenous clastic sediments of the Early and Middle Triassic in South and Central Guizhou, sedimentary sequences and mechanism made those sequences of this area are discussed. In the paper, sediment characteristics and sedimentary sequences, petrologic assemblage of carbonate platform, slope and basin facies is discussed individually, the carbonate platform deposited dolote, bird's-eye, secondary pore dolomite, dolomite breccia and banded limestone. The slope belt developed gravity flow and turbidite, essential petrologic assemblage for thin limestones and limestone breccia, low density turidite and deep wate marls or mudstones occurred in the basin. Sequence stratigraphy of Lower and Middle Triassic in the area is studied in the paper and the paper emphasised in sequence stratigraphy and sea levle changes, two types of sequence boundaries were identified, i.e. , Type I, Indian -Olenekian and Olenekian -Anisian. Type II, Permian -Indian, there are two type II sequence boundaris in the Olenekian, contemporaneously, each depositional sequence composed of lowstand systems tract, transgressive systems tract and highstand systems tract, and lowstand, hightand and transgressive systems tract of each depositional sequence are discussed on petrologic assemblage. According to the relationship between the systems tract and sea level changes, the curves showing the sea level changes in Southern and Central Guizhou during Early and Middle Triassic are also established by the author in this paper, and worker suggest that sedimentary characteristics on carbonate platform, slope and basin be controlled by sea level changing and structual porcess.
1993, 11(4): 42-46.
Abstract:
Origin of gaseous hydrocarbon is discussed on the basis of geochemical characteristics of natural gas in Taibei depression of the Turpan -Hami Basin, Northwestern China. More than 10 gas samples were collected from the production wells. Molecular composition and carbon, hydrogen and helium isotope composition of natural gas were analyzed. The gases contain 60. 85 - 84. 40% mathane and 13. 04-38. 76% heavy hydrocarbons (Cu2+). Values of wetness (C1/C2+) are between 1. 57 to 6. 37. The gases are isotopically characterized by δ18C1 = -43. 0～-49. 4‰, δDc1 = - 220～-271‰, δ18C2 = -20.1～-34. 0‰. δDc2= -259～-257‰. δ18C3= -21.3～-26. 7‰, δDc3= -114～-203‰, δ18C4= -22. 2～-28. 2‰, δDc4 =-93～-116‰, and 3He/4He = (3. 17-7. 01)×10-6. Estimated maturity of natural gas is different from that of Jurassic sediment organic matter. Based on the carbon isotope composition of mathane, ethane and propane, values of vit-rinite reflectance (R.) are calculated. The data indicate that natural gas in Taibei depression of the Tuipan -Hami Basin is wet gas, and belongs to thermocatalytical natural gas, that the gases may be generated in different stages, which causes the gases have larger △13C2-1 values, and that the gases may be partially derived from Jurassic System, and partially from Pre - jurassic strata.
Origin of gaseous hydrocarbon is discussed on the basis of geochemical characteristics of natural gas in Taibei depression of the Turpan -Hami Basin, Northwestern China. More than 10 gas samples were collected from the production wells. Molecular composition and carbon, hydrogen and helium isotope composition of natural gas were analyzed. The gases contain 60. 85 - 84. 40% mathane and 13. 04-38. 76% heavy hydrocarbons (Cu2+). Values of wetness (C1/C2+) are between 1. 57 to 6. 37. The gases are isotopically characterized by δ18C1 = -43. 0～-49. 4‰, δDc1 = - 220～-271‰, δ18C2 = -20.1～-34. 0‰. δDc2= -259～-257‰. δ18C3= -21.3～-26. 7‰, δDc3= -114～-203‰, δ18C4= -22. 2～-28. 2‰, δDc4 =-93～-116‰, and 3He/4He = (3. 17-7. 01)×10-6. Estimated maturity of natural gas is different from that of Jurassic sediment organic matter. Based on the carbon isotope composition of mathane, ethane and propane, values of vit-rinite reflectance (R.) are calculated. The data indicate that natural gas in Taibei depression of the Tuipan -Hami Basin is wet gas, and belongs to thermocatalytical natural gas, that the gases may be generated in different stages, which causes the gases have larger △13C2-1 values, and that the gases may be partially derived from Jurassic System, and partially from Pre - jurassic strata.
1993, 11(4): 56-66.
Abstract:
Quan Songqing Wang Guozhong Lu Bingquan Jiang Panliang (Department of Marine Geology. Tongji University. Shanghai. 200092. China) Paipu Coral Reef Area, about 100 km2 in area, located at the Northwest Part of Hainan Island in the South China Sea , is consist of recent coral fringing reefs, coral barrier reef and their internal water body. Because of the obstacle of the barrier reef in the seaward side and rich supplement of terrigenous elastics from island, in this area exist two kinds of sedimentary environments - the fresh water carbonate sedimentary environment and the muddy water carbonate sedimentary environment. Therefore two sedimentary systems -the fresh water carbonate sedimentary system and muddy water carbonate sedimentary system are formed relatively. In these sedimentary environments accumulate three kinds of sediments; the reefoid sediments, consisted of fresh water coral reef facies and muddy water coral reef facies, the terrigenous sediments and the mixed sediments, deposited in the muddy water environments. In this paper the sedimentary characteristics of all kinds of sediments are described in detail. The framework of muddy water coral reefs is built up by mound - like and massive corals with large and high knob of coralline skeletons and thick tentacles. The low limit of coral growing zone is 3. 4m under the sea level; absent of spurs and grooves systems and lower coverage of growing corals are the other characteristics of muddy water coral reefs. The evolutional process of sedimentary systems is as follows: in the early Holocene epoch a single tel-rigenous clastic sedimentary system existed there, in the time of middle Holocene transgression, the climate was becoming warmer, the early fringing coral reefs and Dachau Barries Coral reef formed, and in the late Holocene epoch, as the barrier coral reef was going into senile stage, the obstacle role of barrier reef was be- coming strong, two kinds of sedimentary systems - fresh water sedimentary system and muddy water sedimentary system formed finally. Authors of this article considered that the percentage of terrigenous elastics and coral debris can be used as the index of the reefoid sedimentary facies and terrigenous sedimentary facies. but the amount of the shell debris can't be used as the inedx of the reefoid or terrigenous sedimentary facies.
Quan Songqing Wang Guozhong Lu Bingquan Jiang Panliang (Department of Marine Geology. Tongji University. Shanghai. 200092. China) Paipu Coral Reef Area, about 100 km2 in area, located at the Northwest Part of Hainan Island in the South China Sea , is consist of recent coral fringing reefs, coral barrier reef and their internal water body. Because of the obstacle of the barrier reef in the seaward side and rich supplement of terrigenous elastics from island, in this area exist two kinds of sedimentary environments - the fresh water carbonate sedimentary environment and the muddy water carbonate sedimentary environment. Therefore two sedimentary systems -the fresh water carbonate sedimentary system and muddy water carbonate sedimentary system are formed relatively. In these sedimentary environments accumulate three kinds of sediments; the reefoid sediments, consisted of fresh water coral reef facies and muddy water coral reef facies, the terrigenous sediments and the mixed sediments, deposited in the muddy water environments. In this paper the sedimentary characteristics of all kinds of sediments are described in detail. The framework of muddy water coral reefs is built up by mound - like and massive corals with large and high knob of coralline skeletons and thick tentacles. The low limit of coral growing zone is 3. 4m under the sea level; absent of spurs and grooves systems and lower coverage of growing corals are the other characteristics of muddy water coral reefs. The evolutional process of sedimentary systems is as follows: in the early Holocene epoch a single tel-rigenous clastic sedimentary system existed there, in the time of middle Holocene transgression, the climate was becoming warmer, the early fringing coral reefs and Dachau Barries Coral reef formed, and in the late Holocene epoch, as the barrier coral reef was going into senile stage, the obstacle role of barrier reef was be- coming strong, two kinds of sedimentary systems - fresh water sedimentary system and muddy water sedimentary system formed finally. Authors of this article considered that the percentage of terrigenous elastics and coral debris can be used as the index of the reefoid sedimentary facies and terrigenous sedimentary facies. but the amount of the shell debris can't be used as the inedx of the reefoid or terrigenous sedimentary facies.
1993, 11(4): 73-77.
Abstract:
This paper has reported primarily the carbon isotope composition of the methane in the soil of the oil/gas anomalous area and that of non-oil /gas area which are situated in arid and semi-arid environments of China. Geochemistry characteristics of methane and heavy hydrocarbons in soils and casbon isotope of the methane are discussed. The following conclusions are drawn: (1)Methane in soils one of important sources of "greenhouse effect" gas - methane. The soil in the arid northern China has good ability to preserve mehtane and heavy hydrocarbons concentration. In the south of China, climate condition make it easy for plant to grow. Because of abundant organic matter and strong biological activity in soils, a great quantity of methane of biological origin existed so it could be produced that a g. owing to poor preservation of methane, compared with that of the northern part of China, the soils in the sourth of China contributed more methane to the atmosphere. (2)Methane in soil of the oil/gas-bearing area is a mixture of methane produced by microbiology and by-migrating to the surface from the underground reservoirs in different proportion. Its contribution of methane to atmosphere is often greater than that of non-oil/gas area. (3)δ13C Values of methane in soil of oil/gas - bearing area are heavier than that of non-oil/gas - bearing, i. e. relatively rich in 13C. There are obvious differences of the δ13C Values of methane in soils between two different areas. (4)δ13C values of methane in soils become heavier because of the surface oxidization and other secondary fractionation. It is valid that the two origin types of methane in soils are judged by δ13C values of methane in soils in association with distribution characteristics of hydrocarbons.
This paper has reported primarily the carbon isotope composition of the methane in the soil of the oil/gas anomalous area and that of non-oil /gas area which are situated in arid and semi-arid environments of China. Geochemistry characteristics of methane and heavy hydrocarbons in soils and casbon isotope of the methane are discussed. The following conclusions are drawn: (1)Methane in soils one of important sources of "greenhouse effect" gas - methane. The soil in the arid northern China has good ability to preserve mehtane and heavy hydrocarbons concentration. In the south of China, climate condition make it easy for plant to grow. Because of abundant organic matter and strong biological activity in soils, a great quantity of methane of biological origin existed so it could be produced that a g. owing to poor preservation of methane, compared with that of the northern part of China, the soils in the sourth of China contributed more methane to the atmosphere. (2)Methane in soil of the oil/gas-bearing area is a mixture of methane produced by microbiology and by-migrating to the surface from the underground reservoirs in different proportion. Its contribution of methane to atmosphere is often greater than that of non-oil/gas area. (3)δ13C Values of methane in soil of oil/gas - bearing area are heavier than that of non-oil/gas - bearing, i. e. relatively rich in 13C. There are obvious differences of the δ13C Values of methane in soils between two different areas. (4)δ13C values of methane in soils become heavier because of the surface oxidization and other secondary fractionation. It is valid that the two origin types of methane in soils are judged by δ13C values of methane in soils in association with distribution characteristics of hydrocarbons.
1993, 11(4): 92-98.
Abstract:
According to the shapes and characteristics of the first basal reflection of illite,i.e. d=10?,this papersums up some methods for measuring the crystallinity indexes of illite,including Weaver index,Kiibler indexand Acute index,Openness index,Weber index,Weber一Dunoyer de Segonzac-Econamou indes,Openingindex and Crystallizing index,and Flehmig index. Each of the indexes may be used as the estimation of crcs-tallizing degree of illite. Based on the variation of the different crystallinity indexes of illite,and the uses ingeology are also summarized in the paper.
According to the shapes and characteristics of the first basal reflection of illite,i.e. d=10?,this papersums up some methods for measuring the crystallinity indexes of illite,including Weaver index,Kiibler indexand Acute index,Openness index,Weber index,Weber一Dunoyer de Segonzac-Econamou indes,Openingindex and Crystallizing index,and Flehmig index. Each of the indexes may be used as the estimation of crcs-tallizing degree of illite. Based on the variation of the different crystallinity indexes of illite,and the uses ingeology are also summarized in the paper.
