1999 Vol. 17, No. 1
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Display Method:
1999, 17(1): 1-8.
Abstract:
Based on the study of stratigraphy and quantitative Sedimentology of eachfundamental sections,according to the “Single Factor Analysis and Comprehensive Mapping Method”,various single factor maps and quantitative lithofacies paleogeography maps of the Majiagou Age,i.e.Majiagou Age 1, Majiagou Age 2,Majiagou Age 3,Majiagou Age 4,Majiagou Age 5 and Majiagou Age 6 of Ordovician in Ordos,have been is studied and mapped.In these lithofacies paleogeography maps,the determination of paleogeographical units is based on quantitative single factor data.The features of the lithofacies paleogeograph of the Majiagou Age 1, Majiagou Age 3 and Majiagou Age 5 are similar,which can be summerized as “outside lands there were flats,in flats there were lagoons,outside flats there were open seas”and “in lagoons there were gypsum and salt”.The features of the lithofacies paleogeograph of the Majiagou Age 2,Majiagou Age 4 and Majiagou Aeg 6 are also similar,which can be summerized as “outside lands there were flats,outside flats there were open seas,in open seas there were banks,outside open seas there were troughs ”.Briefly,during the Majiagou Age there underwent three transgression-regression cycles.The reservoirs of the North Shaanxi Gas Field are the dolostones of the dolomitic flats in Majiagou 5,and the potential reservoirs will be the dolostones of the banks in Majiagou 4. Therefore,the study of the lithofacies paleogeography of Majiagou Age in Ordos has important significance in both geological theory and production.
Based on the study of stratigraphy and quantitative Sedimentology of eachfundamental sections,according to the “Single Factor Analysis and Comprehensive Mapping Method”,various single factor maps and quantitative lithofacies paleogeography maps of the Majiagou Age,i.e.Majiagou Age 1, Majiagou Age 2,Majiagou Age 3,Majiagou Age 4,Majiagou Age 5 and Majiagou Age 6 of Ordovician in Ordos,have been is studied and mapped.In these lithofacies paleogeography maps,the determination of paleogeographical units is based on quantitative single factor data.The features of the lithofacies paleogeograph of the Majiagou Age 1, Majiagou Age 3 and Majiagou Age 5 are similar,which can be summerized as “outside lands there were flats,in flats there were lagoons,outside flats there were open seas”and “in lagoons there were gypsum and salt”.The features of the lithofacies paleogeograph of the Majiagou Age 2,Majiagou Age 4 and Majiagou Aeg 6 are also similar,which can be summerized as “outside lands there were flats,outside flats there were open seas,in open seas there were banks,outside open seas there were troughs ”.Briefly,during the Majiagou Age there underwent three transgression-regression cycles.The reservoirs of the North Shaanxi Gas Field are the dolostones of the dolomitic flats in Majiagou 5,and the potential reservoirs will be the dolostones of the banks in Majiagou 4. Therefore,the study of the lithofacies paleogeography of Majiagou Age in Ordos has important significance in both geological theory and production.
1999, 17(1): 19-23.
Abstract:
The Huayuan Pb -Zn deposi t is one of the large MVT Pb -Zn deposits in western Hunan.w hich is controlled by the carbonate rock in the Upper part of the Qingx udong Format ion of the Low er Cambrain.Thehost rock is algal limestone 、oolite limestone wi th dark zebra argillaceous limestone of continental margin facies.The bitumen is of frequent occurrence in ores and peripheral Cambrain of mining area.The bitumen fill the interg ranular po res or cracks in f ine grain or acaly forms and associated with sphalerite o r galena in ores.The peripheral bitumen is f illing in fault s or crystal interatic of quxrz-barite vein.On the basis of analysis and measure :Romax 、H/C(Atomic ratio), Tmax ℃, Py -Gc, δ12C 、REE and t race elements.The heat-evolutionay grade of bitumen is higher in mining area which is corresponding with g rahamite -Ⅱ stage and also consistent with mineralization-temperature(rang :80 -200 ℃, mean :135 -151 ℃).The type of bitumen is syngenetic-identical strata ty pe and the organic mat ter is possible to come f rom host rock and participated the mineralization of this deposit.
The Huayuan Pb -Zn deposi t is one of the large MVT Pb -Zn deposits in western Hunan.w hich is controlled by the carbonate rock in the Upper part of the Qingx udong Format ion of the Low er Cambrain.Thehost rock is algal limestone 、oolite limestone wi th dark zebra argillaceous limestone of continental margin facies.The bitumen is of frequent occurrence in ores and peripheral Cambrain of mining area.The bitumen fill the interg ranular po res or cracks in f ine grain or acaly forms and associated with sphalerite o r galena in ores.The peripheral bitumen is f illing in fault s or crystal interatic of quxrz-barite vein.On the basis of analysis and measure :Romax 、H/C(Atomic ratio), Tmax ℃, Py -Gc, δ12C 、REE and t race elements.The heat-evolutionay grade of bitumen is higher in mining area which is corresponding with g rahamite -Ⅱ stage and also consistent with mineralization-temperature(rang :80 -200 ℃, mean :135 -151 ℃).The type of bitumen is syngenetic-identical strata ty pe and the organic mat ter is possible to come f rom host rock and participated the mineralization of this deposit.
Study on Lithofacies Paleogeography of Daye Formation of Lower Triassic in the Middle Yangtze Region
1999, 17(1): 38-43.
Abstract:
The study area deals with five provinces,i.e.,ichuan, Guizhou, Hubei,Hunan and Jiangxi.It is mainly in the middle Yangtze region and also include a part of the upper Yangtze region. Daye Formation of lower Triassic is widely distributed in the area and especially well outcropped in the east of Sichuan and west and east of Hubei. The biggest thickness of Daye Formation is 843.8 m and there exist various sedimentary rocks and a well potential of oil and gas. There are two kinds of different rocks in the Daye Formation,i.e.,carbonate rocks and clastic rocks. Carbonate rocks including limestone and dolomites are most widely distributed in the area. This paper has adopts “the single factor analysis and comprehensive mapping method”and the following single factors are selected:thickness, shallow-water grains content, the sedimentary thickness ratio of deep-water to shallow-water, gravity flow sediment content, the basin sedimentary content and terigenous materials content.At the same time, six fundamental single factors are drawn. On the basis of the six fundamental single factor maps,combined with other quantitative and qualitaive information and other regional geological information one piece of lithofacies paleogeographic map of Daye Age of Early Triassic in middle Yangtze region has been drawn. According to the map of the lithofacies paleogeography of Daye Age of Early Triassic,the whole area of the middle Yangtze Sea has six paleogeologic units.From northern area to southern area,there are the north deep-water basin,the northslope,the shallow-water platform,the south slope.the south deep-water basin and south－east clastic beach.From the early period to the late,sedimentary water became shallow,in the last period,the whole sea area uplifted and became carbonate platform.
The study area deals with five provinces,i.e.,ichuan, Guizhou, Hubei,Hunan and Jiangxi.It is mainly in the middle Yangtze region and also include a part of the upper Yangtze region. Daye Formation of lower Triassic is widely distributed in the area and especially well outcropped in the east of Sichuan and west and east of Hubei. The biggest thickness of Daye Formation is 843.8 m and there exist various sedimentary rocks and a well potential of oil and gas. There are two kinds of different rocks in the Daye Formation,i.e.,carbonate rocks and clastic rocks. Carbonate rocks including limestone and dolomites are most widely distributed in the area. This paper has adopts “the single factor analysis and comprehensive mapping method”and the following single factors are selected:thickness, shallow-water grains content, the sedimentary thickness ratio of deep-water to shallow-water, gravity flow sediment content, the basin sedimentary content and terigenous materials content.At the same time, six fundamental single factors are drawn. On the basis of the six fundamental single factor maps,combined with other quantitative and qualitaive information and other regional geological information one piece of lithofacies paleogeographic map of Daye Age of Early Triassic in middle Yangtze region has been drawn. According to the map of the lithofacies paleogeography of Daye Age of Early Triassic,the whole area of the middle Yangtze Sea has six paleogeologic units.From northern area to southern area,there are the north deep-water basin,the northslope,the shallow-water platform,the south slope.the south deep-water basin and south－east clastic beach.From the early period to the late,sedimentary water became shallow,in the last period,the whole sea area uplifted and became carbonate platform.
1999, 17(1): 51-57.
Abstract:
The shore zone in Qinghai Lake is divided into six sedimentary microfacies:longshore bar，mudflat,sand beach,shingle beach,lagoon and subagueous aeolian.Compared with othe lakes in China and abroad,the deposits in the shore zone of Qinghai Lake are featured by their better developed longshore bar and subaqueous aeolian;A large scale of longshore bar and sand beach are distributed in the shore zone of small slope(slope 10°±)and strong wave,longshore current and wind action.There are characteristics of main traction and saltation parts (two parts of saltation) and little suspended load in their grain－size probability curve.The vertical sequences are reversed rhythmite of poorly sorted (δ1＞1) overlying coarse-grained clastics and well-sorted (δ1＜1) underlying fine－grained clastics;The shingle beach distributes mainly in the erosion coast and the areas from alluvial fan or fan delta into the lake.The gravels are homogenous size and well-psephicity,the long-axis of most gravels parallel the lake strandline,the maximam flat surface tend to lake and the dip angle is about 8°±;The mudflats mainly distribute in the lakebay,level lakeshore and stagnant area behind longshore bar;The characteristics of subagueous aeolian have well-sorted (δ1＜1),well-psephicity,deflation hollows of quartz surface,Sk=-0.15-0.21, Kg=0.75-1.13,Md=0.22～0.023 mm,convex-upward and two parts of saltation in the grain-size probability curve.
The shore zone in Qinghai Lake is divided into six sedimentary microfacies:longshore bar，mudflat,sand beach,shingle beach,lagoon and subagueous aeolian.Compared with othe lakes in China and abroad,the deposits in the shore zone of Qinghai Lake are featured by their better developed longshore bar and subaqueous aeolian;A large scale of longshore bar and sand beach are distributed in the shore zone of small slope(slope 10°±)and strong wave,longshore current and wind action.There are characteristics of main traction and saltation parts (two parts of saltation) and little suspended load in their grain－size probability curve.The vertical sequences are reversed rhythmite of poorly sorted (δ1＞1) overlying coarse-grained clastics and well-sorted (δ1＜1) underlying fine－grained clastics;The shingle beach distributes mainly in the erosion coast and the areas from alluvial fan or fan delta into the lake.The gravels are homogenous size and well-psephicity,the long-axis of most gravels parallel the lake strandline,the maximam flat surface tend to lake and the dip angle is about 8°±;The mudflats mainly distribute in the lakebay,level lakeshore and stagnant area behind longshore bar;The characteristics of subagueous aeolian have well-sorted (δ1＜1),well-psephicity,deflation hollows of quartz surface,Sk=-0.15-0.21, Kg=0.75-1.13,Md=0.22～0.023 mm,convex-upward and two parts of saltation in the grain-size probability curve.
Sequence Stratigraphic Framework and Its Characteristics of the Carboniferous-Permian in North China
1999, 17(1): 63-70.
Abstract:
The Carboniferous-Permian depositonal formation in North China Consists of mixed carbonate/siliciclastic coal-bearing formation and red siliciclastic rock formeration.The former formed in platform-barrier island complex system and shallow water delta system,and the latter formed in fluvial and lacustrine system. The outcrop sequence stratigraphic methodology was applied to research the Carboniferous-Permian depositional formation in North China.The results showed that there exists a special type 1 sequence boundary that lacks the incised valley and its fills in epeiric sea basin(the authors called it as type Ⅰe sequence boundary). The condensed sections are shallow water carbonate rock and siliceous sponge spicule rock or siliceous mudstone that formed at the period of sea-level rised rapidly.There are 4 kinds of parasequeuce that are bottom type,platform-barrier island complex type, siliciclasitc shoreline type and fluviolacustrine type parasequence. According to unconformities and other markes,the Carboniferous-Permian depsitional formation in North China is subdivided to 5 sequeces which belongs to 3 kinds of sequence stratigraphic models. Sequence 1,2and 3 are epeiric sea type sequences, their bottom are type Ⅰesequence boundary.The sequences developed only transgressive and highstand systems tracts, and the condensed sections are shallow water carbonate rocks with the properties of low hydrochloric asid nonsoluble residual,low content of trace-elements and high ratio of Fe2+/Fe3+.Each systems tract includes several parasequences.Most of them consists of limestone in basal, siliciclastic rock in middle and coalbed in top,which reflected the cycles of relative sea-level repidly rise up and slowly fall down. Sequence 4 is transition type sequence.Its bottom is type 1 sequence boundary,and the condensed section is shallow-water siliceous sponge spicule rock or siliceous mudstone with the thichness of 20-30cm.This sequence includes lowstand, transgressive and highstand systems tract. Most of the parasequences in the systems tracts ended with coalbed.Sequence 5 is the nonmarine sequence(red siliciclastic rock formation).Its bottom is type 1 sequence boundary,and includes lowstand,water transgressive and highstand systems tracts(as our personal work is limited.the parasequences are not subdivided at present). The development of Carboniferous-Permian basin-fill supper sequences in North Chena is controlled by second order sea-level change,and the development of depositional sequence mainly controlled by riginal orogeny.
The Carboniferous-Permian depositonal formation in North China Consists of mixed carbonate/siliciclastic coal-bearing formation and red siliciclastic rock formeration.The former formed in platform-barrier island complex system and shallow water delta system,and the latter formed in fluvial and lacustrine system. The outcrop sequence stratigraphic methodology was applied to research the Carboniferous-Permian depositional formation in North China.The results showed that there exists a special type 1 sequence boundary that lacks the incised valley and its fills in epeiric sea basin(the authors called it as type Ⅰe sequence boundary). The condensed sections are shallow water carbonate rock and siliceous sponge spicule rock or siliceous mudstone that formed at the period of sea-level rised rapidly.There are 4 kinds of parasequeuce that are bottom type,platform-barrier island complex type, siliciclasitc shoreline type and fluviolacustrine type parasequence. According to unconformities and other markes,the Carboniferous-Permian depsitional formation in North China is subdivided to 5 sequeces which belongs to 3 kinds of sequence stratigraphic models. Sequence 1,2and 3 are epeiric sea type sequences, their bottom are type Ⅰesequence boundary.The sequences developed only transgressive and highstand systems tracts, and the condensed sections are shallow water carbonate rocks with the properties of low hydrochloric asid nonsoluble residual,low content of trace-elements and high ratio of Fe2+/Fe3+.Each systems tract includes several parasequences.Most of them consists of limestone in basal, siliciclastic rock in middle and coalbed in top,which reflected the cycles of relative sea-level repidly rise up and slowly fall down. Sequence 4 is transition type sequence.Its bottom is type 1 sequence boundary,and the condensed section is shallow-water siliceous sponge spicule rock or siliceous mudstone with the thichness of 20-30cm.This sequence includes lowstand, transgressive and highstand systems tract. Most of the parasequences in the systems tracts ended with coalbed.Sequence 5 is the nonmarine sequence(red siliciclastic rock formation).Its bottom is type 1 sequence boundary,and includes lowstand,water transgressive and highstand systems tracts(as our personal work is limited.the parasequences are not subdivided at present). The development of Carboniferous-Permian basin-fill supper sequences in North Chena is controlled by second order sea-level change,and the development of depositional sequence mainly controlled by riginal orogeny.
1999, 17(1): 84-120.
Abstract:
The carbon isotope compositions of the Late Permian carbonate rocks in central Guangxi show a sharp decrease at the boundary between Wujiapingian and Changxingian(W/C) stages.The limestone samples of the Wujiapingian stage have the δ13C values higher than 3.2‰,whereas the Changingian samples have the δ13C values lower than 3.2‰.This negative shift is suggested to be used to distingush the Wujiapingian and Changxingian stages.The carbon isotope depletion at the W/C boundary is believed to be related to the termination of the coal accumulation in large areas such as the India,eastern Australia,and South Africa but not southern China.The cessation of the coal accumulation and the oxidation of the previously buried coals as a result of the tectonic uplift may release12C rich CO2 into the atmosphere which further leads to the decrease of the δ13C values in ocean water and the marine carbonate rocks.
The carbon isotope compositions of the Late Permian carbonate rocks in central Guangxi show a sharp decrease at the boundary between Wujiapingian and Changxingian(W/C) stages.The limestone samples of the Wujiapingian stage have the δ13C values higher than 3.2‰,whereas the Changingian samples have the δ13C values lower than 3.2‰.This negative shift is suggested to be used to distingush the Wujiapingian and Changxingian stages.The carbon isotope depletion at the W/C boundary is believed to be related to the termination of the coal accumulation in large areas such as the India,eastern Australia,and South Africa but not southern China.The cessation of the coal accumulation and the oxidation of the previously buried coals as a result of the tectonic uplift may release12C rich CO2 into the atmosphere which further leads to the decrease of the δ13C values in ocean water and the marine carbonate rocks.
1999, 17(1): 100-105.
Abstract:
Lower-Tertiry reservior in Lunpola Basin underwent a series of dianenesis,such as compaction,cementation,solution,cracking et al.The diagenesis was very complex,the diagenetic phenomenon is very rich and the diagenetic characters is very obvious.The diagenesis contrllingfactors study of reservior property show that compaction, cementation are two important diagenetic-faxtors which make physical property bad and porosity down in reservior.Solution, particularly solution in deep burial is one of important diagenetic comtrolling-factors which improved reservior property and make physical property well in reservior.
Lower-Tertiry reservior in Lunpola Basin underwent a series of dianenesis,such as compaction,cementation,solution,cracking et al.The diagenesis was very complex,the diagenetic phenomenon is very rich and the diagenetic characters is very obvious.The diagenesis contrllingfactors study of reservior property show that compaction, cementation are two important diagenetic-faxtors which make physical property bad and porosity down in reservior.Solution, particularly solution in deep burial is one of important diagenetic comtrolling-factors which improved reservior property and make physical property well in reservior.
1999, 17(1): 120-126.
Abstract:
The relative abundance and composition characteristics of thiophene-type compounds for typical crude oils in Tarin Basin were analysed and studied systematically using GC-MS-MS technique. The results suggest the relative abundance between benzonaphiothiophene and dibenzothiophene series of % toatal polycyclic aromatic hydrocarbons for different types of crude oils are obvious differences,the contents of marine oils are the higest,contents of lacustrine oils are lower and that of coal-forming oils are the lowest.In this paper,we propose some new organic geochemical parameters for distinguishing marine oil and lacustrine oil using the ratio values of 4-dimethyldibenzothiophene(MDBT)/dibenzothiophene(DBT) as well as (2+3)-MDBT/DBT,for distinguishing marine marl-sourced oil and marine carbonate-sourced oil using the ratio value of 1-MDBT/DBT.Marine oils and coal-forming oils show a predominance of alkylated DBT homologues over the unsubstituted parent,but laustrine oils differ from marine oils and coal-forming oils.However,the maximum degree of alkylation(the most abundance alkylation homologues within any given DBT series) varies,marine oils show a high degree of alkylation,which non-marine oils generally exhibit a lower degree of alkylation.So there is increasing decrease trends from marine marl-sourced oils and marine carbonat-sourced oils to laustrine oils and coal-forming oils.We propose that alkylation trends reflect differences of crosslinking or branching on aliphatic and cyclic moieties in sulfur-rich vs.sulfur-poor kcrogens.
The relative abundance and composition characteristics of thiophene-type compounds for typical crude oils in Tarin Basin were analysed and studied systematically using GC-MS-MS technique. The results suggest the relative abundance between benzonaphiothiophene and dibenzothiophene series of % toatal polycyclic aromatic hydrocarbons for different types of crude oils are obvious differences,the contents of marine oils are the higest,contents of lacustrine oils are lower and that of coal-forming oils are the lowest.In this paper,we propose some new organic geochemical parameters for distinguishing marine oil and lacustrine oil using the ratio values of 4-dimethyldibenzothiophene(MDBT)/dibenzothiophene(DBT) as well as (2+3)-MDBT/DBT,for distinguishing marine marl-sourced oil and marine carbonate-sourced oil using the ratio value of 1-MDBT/DBT.Marine oils and coal-forming oils show a predominance of alkylated DBT homologues over the unsubstituted parent,but laustrine oils differ from marine oils and coal-forming oils.However,the maximum degree of alkylation(the most abundance alkylation homologues within any given DBT series) varies,marine oils show a high degree of alkylation,which non-marine oils generally exhibit a lower degree of alkylation.So there is increasing decrease trends from marine marl-sourced oils and marine carbonat-sourced oils to laustrine oils and coal-forming oils.We propose that alkylation trends reflect differences of crosslinking or branching on aliphatic and cyclic moieties in sulfur-rich vs.sulfur-poor kcrogens.
1999, 17(1): 130-155.
Abstract:
The relative high abundance and important hydrocabon-generating potentiality of fatty acids in geological bodios make it necessary to investigate the composition、distrbution and presence of fatty acids in various geological bodies.The composition and distribution features of fatty acids in immature oils of diferent sedimentary environments,sach the alkaline salt lake facies in the Migang depression, Halite salt lake facies in the Wayang depression,ggpsum salt lake facies in the Xiangcheng depression and fresh water lake facies in the Nanyang depression were analysed and investigated. As a result,the fatty acids in immature oils of various salt tale depressions are compased of saturated n-fatty acids,unsaturated n-fatty acids,branched fatty acids, isoprenoid fatty acids and fatty acid ethyl eslers with different abundances The carbon number of fatty acids is between C12 to C30 major at C16 and C18 and the short-chain homologumes are predominant with a strong even／odd predommance,The unsaturated n-fatty acids are mainly composed of C16:1△9 C18:1△9 and C18:1△11 fatty acids,and the UFA／TFA values ranged between 0.013 to 0.091(average values:0.042).The branched fatty acids are composed of C15、C17 iso-anteiso-fatty acids and C14～C21 isoprenoid fatty acids (except for C18).Thes results and the low C16／C18、C18:1 values indicate that the source materials of the immature oils are mainly bacteria、algae and the bacteriol alternated products of higher plants and aquaticorganisms.Thas,the composition and distribution features of fatty acids in immature oils can be used to explain the sources of primary organic matter in these various deperssions.On the other hand,the C11～C25 ethyl esters of fatty acids with laoer even／odd prodominance fourd in various sedimentary environments clemonstrate that the fatty acids can present as esters in geological bodies.
The relative high abundance and important hydrocabon-generating potentiality of fatty acids in geological bodios make it necessary to investigate the composition、distrbution and presence of fatty acids in various geological bodies.The composition and distribution features of fatty acids in immature oils of diferent sedimentary environments,sach the alkaline salt lake facies in the Migang depression, Halite salt lake facies in the Wayang depression,ggpsum salt lake facies in the Xiangcheng depression and fresh water lake facies in the Nanyang depression were analysed and investigated. As a result,the fatty acids in immature oils of various salt tale depressions are compased of saturated n-fatty acids,unsaturated n-fatty acids,branched fatty acids, isoprenoid fatty acids and fatty acid ethyl eslers with different abundances The carbon number of fatty acids is between C12 to C30 major at C16 and C18 and the short-chain homologumes are predominant with a strong even／odd predommance,The unsaturated n-fatty acids are mainly composed of C16:1△9 C18:1△9 and C18:1△11 fatty acids,and the UFA／TFA values ranged between 0.013 to 0.091(average values:0.042).The branched fatty acids are composed of C15、C17 iso-anteiso-fatty acids and C14～C21 isoprenoid fatty acids (except for C18).Thes results and the low C16／C18、C18:1 values indicate that the source materials of the immature oils are mainly bacteria、algae and the bacteriol alternated products of higher plants and aquaticorganisms.Thas,the composition and distribution features of fatty acids in immature oils can be used to explain the sources of primary organic matter in these various deperssions.On the other hand,the C11～C25 ethyl esters of fatty acids with laoer even／odd prodominance fourd in various sedimentary environments clemonstrate that the fatty acids can present as esters in geological bodies.
1999, 17(1): 141-144.
Abstract:
Dow(1977) observed that vitrinite reflectance profiles that pass through an unconformity commonly exhibit an offset at the unconformity.And the offset could be used to estimate the amount of missing section.The estimation is accomplished graphically by projecting the preunconformity portion of the profile upward to the point where it attains a value equal to the vitrinite reflectance immediately above the unconformity.The vertical distance between this point and the unconformity was presented as the amount of missing section.This method has been widely used since the late 70's.And its inaccuracy is getting more and more apparent through further application.This paper presents a detailed study on the organic maturation of vitrinite during the burying-uplifting-reburing process.An organic maturity modeling,which integrates complete thermal and burial histories,is used.By the principle of reaction kinetics,it is assuned that the maturation process of the section below the unconformity continues during the erosional phase and the reburial phase.During the reburial phase,the sections above and below the unconformity undergo continued maturation (increases in cumulative TTI values) at different reaction rates,and results in a difference of organic maturation between the two sections. So the difference can be used to trace their burial histories of these sections.And then we proposes a corrected method to estimate the thickness of sediment removed at an unconformity using vitrinite reflectance data of the formations blow and above the unconformity.which can get a more accurate result than Dow's one.
Dow(1977) observed that vitrinite reflectance profiles that pass through an unconformity commonly exhibit an offset at the unconformity.And the offset could be used to estimate the amount of missing section.The estimation is accomplished graphically by projecting the preunconformity portion of the profile upward to the point where it attains a value equal to the vitrinite reflectance immediately above the unconformity.The vertical distance between this point and the unconformity was presented as the amount of missing section.This method has been widely used since the late 70's.And its inaccuracy is getting more and more apparent through further application.This paper presents a detailed study on the organic maturation of vitrinite during the burying-uplifting-reburing process.An organic maturity modeling,which integrates complete thermal and burial histories,is used.By the principle of reaction kinetics,it is assuned that the maturation process of the section below the unconformity continues during the erosional phase and the reburial phase.During the reburial phase,the sections above and below the unconformity undergo continued maturation (increases in cumulative TTI values) at different reaction rates,and results in a difference of organic maturation between the two sections. So the difference can be used to trace their burial histories of these sections.And then we proposes a corrected method to estimate the thickness of sediment removed at an unconformity using vitrinite reflectance data of the formations blow and above the unconformity.which can get a more accurate result than Dow's one.
1999, 17(1): 149-155.
Abstract:
Reported in this paper are the REE distribution patterns,character parameter and correlation coefficient between REE &primary elements in Quarternary sediments of Changliushui section developed at a depressed qully at Zhongwci County of Ningxia Rcgion, ncar the southcrn margin of the Ala Shant Desert in North－West China.The material source of the fluvo－lacustrine deposits and the evolutionary of the climate and the environment in the desert front area also discussed here in the section,there are three main climatic and environmental changes from dry and cool to warm and moist during deposition,and four or five secondary climatic fluctuations.At the depth of 2.7 m,the content of REE change very clearly.It seems a eflection of temperate period of Holocene in the area (9300～54300 a.B.P.).REE characters show that the source of the aeolian sans of the deposit area mainly came from surrounding parent rock material. Additionally,it also possible that the weathered material of Jurassic rock was brougt into the sedimentary series by washing.The chane of sedimentary facirs from aeolion to fluvial thcn to lacustinc origins synchronusly coincied with the changc of climate from dry－cold cold-moist to warm moist.The arid desert environment is dominant,in which the chemical and wethering processes are weak.
Reported in this paper are the REE distribution patterns,character parameter and correlation coefficient between REE &primary elements in Quarternary sediments of Changliushui section developed at a depressed qully at Zhongwci County of Ningxia Rcgion, ncar the southcrn margin of the Ala Shant Desert in North－West China.The material source of the fluvo－lacustrine deposits and the evolutionary of the climate and the environment in the desert front area also discussed here in the section,there are three main climatic and environmental changes from dry and cool to warm and moist during deposition,and four or five secondary climatic fluctuations.At the depth of 2.7 m,the content of REE change very clearly.It seems a eflection of temperate period of Holocene in the area (9300～54300 a.B.P.).REE characters show that the source of the aeolian sans of the deposit area mainly came from surrounding parent rock material. Additionally,it also possible that the weathered material of Jurassic rock was brougt into the sedimentary series by washing.The chane of sedimentary facirs from aeolion to fluvial thcn to lacustinc origins synchronusly coincied with the changc of climate from dry－cold cold-moist to warm moist.The arid desert environment is dominant,in which the chemical and wethering processes are weak.
1999, 17(1): 161-165.
Abstract:
The following results are obtained from the study of taphonomic characteristics fossil taphonomic sequence and sedimentary sequence of early metazoen biota discovered in China:(1)The emdedded and preserved condition is controlled by event layer(tempestite or turbidite)ard sedimentation rate takes main part in fossil embedition and preservation.(2)Close relationship preservation of the early metazoen biota between sea-level changes,this is,which always occur in transgressive system of shallow water bay and restricted sea, early metazoen biota occur in the shelf margin systems. Based on sedimentary evironments of the early metazoen biota.two buried models of the early metazoen biota are established Eventualy,it is indicated that new early metazoen biota may be discovered by above-mentioned condition which is benefit to preserve biota.
The following results are obtained from the study of taphonomic characteristics fossil taphonomic sequence and sedimentary sequence of early metazoen biota discovered in China:(1)The emdedded and preserved condition is controlled by event layer(tempestite or turbidite)ard sedimentation rate takes main part in fossil embedition and preservation.(2)Close relationship preservation of the early metazoen biota between sea-level changes,this is,which always occur in transgressive system of shallow water bay and restricted sea, early metazoen biota occur in the shelf margin systems. Based on sedimentary evironments of the early metazoen biota.two buried models of the early metazoen biota are established Eventualy,it is indicated that new early metazoen biota may be discovered by above-mentioned condition which is benefit to preserve biota.
1999, 17(1): 9-18.
Abstract:
The experimental methods of accumulation metal and mineralization by algae-bacteria are introduced as follow: I.A artificial development on large scale algal mats have been carried out in Guan-rao saltwork,Shandong Province, from 1992-1996.According to last examination on December 2,1996,the thickness of algal mats come up 2.5cm. The sediment microzones with relating redox-gradient,which are developing in the algal mats,on the test pond floors have a strong influence for the mobilization and fixation of irons and sulfide.The precipitation of inorganic calcium carbonate(CaCO3)and gypsum (CaSO4)formed in the algal mats. As a result of the decay of organic matter in the black layer,an anaerobic microenviroment appears where hydrogen sulfide(H2S) is produced by the activity of sulfate reducing bacteria. Organic matters from algal mats are divided into more than 335 compounds which could accumulate metal ions. Iron,which is bound on clay and other minerals,and which is dissolved also in the pore water,is in solution as Fe2+ underneath the black layer and precipitates as Fe3+,ferric oxide above the algal mats. In this higher productivity microenvironment of such an algal mat,the redox gradients are very high (more than 200mv Eh-difference between above and below the algal mat). Contents(‰) of some complex ions in the polysaccharide and protein from algal mats show that the Al,Ca,Fe,Mg, Sr,Zn in protein,are more than that in polysaccharide. Ⅱ.The tests of accumulating Au by algae,bacteria and fungi 1.Bacteria and Fungi Thiobacillus ferrooxiduns and Thiobacillus thiooxidans were separated from Tongling Au ore deposit.The results of culture experiment and test by X-ray-diffracterometer evidence that both generally existed in the mineral body,and from sulphate and H2SO4,changed the environment into acidity and the organic matters produced by bacteria decay could enrich the Au.The experiment made by Aspergillus niger also evidence the accumulation of Au. 2.The experimental results made by Lyngbya confercides,Spirulina platensis,Spirulina subsalsa of Cyanophyta and Chorella pyrenoidosa, Kirchneriate lunaris of Chlorophyat show that the activities of algal growth changed the blance of the ions systems CO2-HCO- 3-CO2- 3 and Ca2+-Mg2+-Na+-PO3-4-Au2+,and,resulting in the rise of pH and the drop of Eh during growth stage.The Au contents accumulated by these algae are 3.74-20.354 times of cultural liquor concentrations,after growth for three weeks. 3.Algal action on formation and deposition of phosphates. The algae used in experiment are Spirulina platensis of Cyanophyta. (1)The OD value of algal growth was determined by a Model 721 spectrophoto-meter in 560nm wavelength. (2)The pH and Eh value of algal liquor was measured by a data acquisition system connected with a Model 251 glass electrode and a saturated calomal electrode was used for comparison.The surveying system consists of a sharp PC-1500A computer with a CE-printer and a 86-4D/A convertor. (3)The determination of the PO3-4 concentration was performed with a 721 spectrophotometer connected to computerized data acquisition system. (4)The tests of accumulation of phosphorus in algal cells were made by six 2L beakers,which were divided three groups.In group (1),the K2HPO4 concentration is 0.5g/L,in group (2) it is 1.5g/L,and in group (3)it is 2.5g/L. They were cultured under the onditional illumination of 2200LX.light/dark as 16/8h. (5)Phosphorus compounds (inorganic phosphate,ATP,ADP,polyphosphate containing phosphohexose,nucleotide and phosphate ester in algal cells)were extracted (as Liu Zhi-li et al,1996). (6)Mineralogical determinations were made with a D/MAX rotating anode X-ray diffracterometer. The results show that after the algal logarthmic growth stage,the pH Value rose From 8.323 to 9.027 (average value),the Eh dropped from 0.4259V to 0.2828V.Spirulina platensis could grow in the cultural liquor that contained PO3-4 ionic concentration up to 7.25g/L.After a growth cycle of the algae,the PO3-4 concentration in the cultural liquor dropped to an absolute value,0.9g/L,and white deposits of calcium magnesium phosphate ［Ca2Mg(PO4)2.2H2O］ and calcium sodium carbonates［Na2Ca(CO3) 2.5H2O］ were separated from bottom of the bottles.The results of simulated test of mineralization show that under the normal atmospheric temperture and presure and in the Ca2+-HPO2-4-F-HCO3 -H2O system,the polyphosphate extracted from algal cels of Spirulina subsalsa may form mineral deposits which contain mainly carbonate fluorapatite,calcite and non-crystal phosphorus. Simulated tests of algae and ist organic matters actions on formatoin and deposition of the Cu,Mn,Zn etc.also show that algae and it's organic matter have important signification in the accumulation of metal ions.
The experimental methods of accumulation metal and mineralization by algae-bacteria are introduced as follow: I.A artificial development on large scale algal mats have been carried out in Guan-rao saltwork,Shandong Province, from 1992-1996.According to last examination on December 2,1996,the thickness of algal mats come up 2.5cm. The sediment microzones with relating redox-gradient,which are developing in the algal mats,on the test pond floors have a strong influence for the mobilization and fixation of irons and sulfide.The precipitation of inorganic calcium carbonate(CaCO3)and gypsum (CaSO4)formed in the algal mats. As a result of the decay of organic matter in the black layer,an anaerobic microenviroment appears where hydrogen sulfide(H2S) is produced by the activity of sulfate reducing bacteria. Organic matters from algal mats are divided into more than 335 compounds which could accumulate metal ions. Iron,which is bound on clay and other minerals,and which is dissolved also in the pore water,is in solution as Fe2+ underneath the black layer and precipitates as Fe3+,ferric oxide above the algal mats. In this higher productivity microenvironment of such an algal mat,the redox gradients are very high (more than 200mv Eh-difference between above and below the algal mat). Contents(‰) of some complex ions in the polysaccharide and protein from algal mats show that the Al,Ca,Fe,Mg, Sr,Zn in protein,are more than that in polysaccharide. Ⅱ.The tests of accumulating Au by algae,bacteria and fungi 1.Bacteria and Fungi Thiobacillus ferrooxiduns and Thiobacillus thiooxidans were separated from Tongling Au ore deposit.The results of culture experiment and test by X-ray-diffracterometer evidence that both generally existed in the mineral body,and from sulphate and H2SO4,changed the environment into acidity and the organic matters produced by bacteria decay could enrich the Au.The experiment made by Aspergillus niger also evidence the accumulation of Au. 2.The experimental results made by Lyngbya confercides,Spirulina platensis,Spirulina subsalsa of Cyanophyta and Chorella pyrenoidosa, Kirchneriate lunaris of Chlorophyat show that the activities of algal growth changed the blance of the ions systems CO2-HCO- 3-CO2- 3 and Ca2+-Mg2+-Na+-PO3-4-Au2+,and,resulting in the rise of pH and the drop of Eh during growth stage.The Au contents accumulated by these algae are 3.74-20.354 times of cultural liquor concentrations,after growth for three weeks. 3.Algal action on formation and deposition of phosphates. The algae used in experiment are Spirulina platensis of Cyanophyta. (1)The OD value of algal growth was determined by a Model 721 spectrophoto-meter in 560nm wavelength. (2)The pH and Eh value of algal liquor was measured by a data acquisition system connected with a Model 251 glass electrode and a saturated calomal electrode was used for comparison.The surveying system consists of a sharp PC-1500A computer with a CE-printer and a 86-4D/A convertor. (3)The determination of the PO3-4 concentration was performed with a 721 spectrophotometer connected to computerized data acquisition system. (4)The tests of accumulation of phosphorus in algal cells were made by six 2L beakers,which were divided three groups.In group (1),the K2HPO4 concentration is 0.5g/L,in group (2) it is 1.5g/L,and in group (3)it is 2.5g/L. They were cultured under the onditional illumination of 2200LX.light/dark as 16/8h. (5)Phosphorus compounds (inorganic phosphate,ATP,ADP,polyphosphate containing phosphohexose,nucleotide and phosphate ester in algal cells)were extracted (as Liu Zhi-li et al,1996). (6)Mineralogical determinations were made with a D/MAX rotating anode X-ray diffracterometer. The results show that after the algal logarthmic growth stage,the pH Value rose From 8.323 to 9.027 (average value),the Eh dropped from 0.4259V to 0.2828V.Spirulina platensis could grow in the cultural liquor that contained PO3-4 ionic concentration up to 7.25g/L.After a growth cycle of the algae,the PO3-4 concentration in the cultural liquor dropped to an absolute value,0.9g/L,and white deposits of calcium magnesium phosphate ［Ca2Mg(PO4)2.2H2O］ and calcium sodium carbonates［Na2Ca(CO3) 2.5H2O］ were separated from bottom of the bottles.The results of simulated test of mineralization show that under the normal atmospheric temperture and presure and in the Ca2+-HPO2-4-F-HCO3 -H2O system,the polyphosphate extracted from algal cels of Spirulina subsalsa may form mineral deposits which contain mainly carbonate fluorapatite,calcite and non-crystal phosphorus. Simulated tests of algae and ist organic matters actions on formatoin and deposition of the Cu,Mn,Zn etc.also show that algae and it's organic matter have important signification in the accumulation of metal ions.
1999, 17(1): 30-37.
Abstract:
In the South of Anhui and West of Zhejiang, there is a zo ne of upper Sinian and low er Cambrian siliceous rocks w hich strech strch praximately NE.Af ter field t rip and labo ratory studies,We understood all aspects of thier tex ture and structure and mineral composi tio n and found shell of radiolarian.It is proved that biogenic procession plays an important role in the fomat ion of chert s of chert s and the analy sis of major elements shows it clearly.
In the South of Anhui and West of Zhejiang, there is a zo ne of upper Sinian and low er Cambrian siliceous rocks w hich strech strch praximately NE.Af ter field t rip and labo ratory studies,We understood all aspects of thier tex ture and structure and mineral composi tio n and found shell of radiolarian.It is proved that biogenic procession plays an important role in the fomat ion of chert s of chert s and the analy sis of major elements shows it clearly.
1999, 17(1): 44-50.
Abstract:
Qiantongshan giant lead-zinc ore deposit,Feng County,Shanxi Province occurs at Middle Devonian sedmentaty facies formed by hot fluid. With higher contents of SiO２、FeO、CaO、MgO、MnO、As、Sb、Cu、Pb、Zn、Ag、B、Ba,five sedmentary-metasomatic, syngenetic-sedimentary subfacies formed by hot fluid and sedimentary subfacies of hot fluid imposed by epigenetic hot fluid.These subfacies were formed by syngenetic sedimentation and metasomatism which were produced by mixing of Ca２＋－Mg２＋－K＋－HCO－３－Cl－type of ore forming fluid with higher contents of Fe2+adn Si4+,Ca２＋－Mg２＋－SO２－－Cl－（CO２－CO－H２O）type of ore-forming fluid with higher contents of Si4+and sea water with higher salinity.Migration mechanism of ore-forming fluid at large-scale were possible caused by the compression produced by the Qinling subplate subducing into the Huabei plate deeply.Ore-forming fluid migrated up along syngenetic fault and moved into basins which were caused by the extension of Earth Crust at surface.So sedimentaty facies of hot fluid occured.
Qiantongshan giant lead-zinc ore deposit,Feng County,Shanxi Province occurs at Middle Devonian sedmentaty facies formed by hot fluid. With higher contents of SiO２、FeO、CaO、MgO、MnO、As、Sb、Cu、Pb、Zn、Ag、B、Ba,five sedmentary-metasomatic, syngenetic-sedimentary subfacies formed by hot fluid and sedimentary subfacies of hot fluid imposed by epigenetic hot fluid.These subfacies were formed by syngenetic sedimentation and metasomatism which were produced by mixing of Ca２＋－Mg２＋－K＋－HCO－３－Cl－type of ore forming fluid with higher contents of Fe2+adn Si4+,Ca２＋－Mg２＋－SO２－－Cl－（CO２－CO－H２O）type of ore-forming fluid with higher contents of Si4+and sea water with higher salinity.Migration mechanism of ore-forming fluid at large-scale were possible caused by the compression produced by the Qinling subplate subducing into the Huabei plate deeply.Ore-forming fluid migrated up along syngenetic fault and moved into basins which were caused by the extension of Earth Crust at surface.So sedimentaty facies of hot fluid occured.
1999, 17(1): 58-62.
Abstract:
On the basis of core scaling logging data, the logging data interpretation model of Silurian sedimentary micro facies in Tazhong area is established by comprehensive application of conventional logging,natural gamma ray spectrometry(NGS),diplog and image log data.The Silurian in the study area consist of detritus tidal flat deposits,which is divided into subtidal sand flat, tidal channel,intertidal mixed flat and supratidal mudflat.Four logging-sequence boundaries are recongnized.The top and bottom of the Silurian belong to type-I sequence boundary,and its interior belong to type-Ⅱ sequence boundary. Characteristics of these sequence boundaries are described as follows: 1) the pattern in conventional logging and NGS curves is step- sudden change contact, 2) obvious difference either size or direction of dip vectors in the result map of stratum dip vector,3) both stratigraphic attitude and contact relation are also obviously different in FMI images. The Silurian is divided into 3 logging -sequences.which are named as sequenceⅠ,Ⅱ and Ⅲ from the bottom to the top and each one is composed of transgressive system tract(TST)and high stand system tract(HST).TST is mainly sand flat and mixed flat deposits, whose parasequence superimposed pattern shows that the grain size and ratio of sand to mud increase in the vertical, and retrograding bell-shaped series in GR and SP curves.HST is composed of mixed flat and mudflat, whose parasequence superimposed pattern shows that mudrock increases.sand decreases,and ratio of sand to mud decreases in the vertical, which forms accretionary parasequence group,and the straight-ling or box appear in GR and SP curves.By comprehensive analysis of sequence stratigraphy, it is shown that different eustatic rate of relative sea-level result in regular change of accommodation and superimposition in the vertical of microfacies in the transversal of each sequence.By palaeocurrent statistics and analysis from sequence Ⅰ to Ⅲ, it can be seen that current direction in Silurian of this area is double, which is mainly NE-SE.The above analysis shows that logging data is important for the study of sequence stratigraphy,especially for determining stratigraphic series, recognizing sequence boundary,dividing sequence and system tracts and determining palaeocurrent direction.The method is intuitive and clear.
On the basis of core scaling logging data, the logging data interpretation model of Silurian sedimentary micro facies in Tazhong area is established by comprehensive application of conventional logging,natural gamma ray spectrometry(NGS),diplog and image log data.The Silurian in the study area consist of detritus tidal flat deposits,which is divided into subtidal sand flat, tidal channel,intertidal mixed flat and supratidal mudflat.Four logging-sequence boundaries are recongnized.The top and bottom of the Silurian belong to type-I sequence boundary,and its interior belong to type-Ⅱ sequence boundary. Characteristics of these sequence boundaries are described as follows: 1) the pattern in conventional logging and NGS curves is step- sudden change contact, 2) obvious difference either size or direction of dip vectors in the result map of stratum dip vector,3) both stratigraphic attitude and contact relation are also obviously different in FMI images. The Silurian is divided into 3 logging -sequences.which are named as sequenceⅠ,Ⅱ and Ⅲ from the bottom to the top and each one is composed of transgressive system tract(TST)and high stand system tract(HST).TST is mainly sand flat and mixed flat deposits, whose parasequence superimposed pattern shows that the grain size and ratio of sand to mud increase in the vertical, and retrograding bell-shaped series in GR and SP curves.HST is composed of mixed flat and mudflat, whose parasequence superimposed pattern shows that mudrock increases.sand decreases,and ratio of sand to mud decreases in the vertical, which forms accretionary parasequence group,and the straight-ling or box appear in GR and SP curves.By comprehensive analysis of sequence stratigraphy, it is shown that different eustatic rate of relative sea-level result in regular change of accommodation and superimposition in the vertical of microfacies in the transversal of each sequence.By palaeocurrent statistics and analysis from sequence Ⅰ to Ⅲ, it can be seen that current direction in Silurian of this area is double, which is mainly NE-SE.The above analysis shows that logging data is important for the study of sequence stratigraphy,especially for determining stratigraphic series, recognizing sequence boundary,dividing sequence and system tracts and determining palaeocurrent direction.The method is intuitive and clear.
1999, 17(1): 78-83.
Abstract:
It is expounded the probing of the high resolution subbottom profile on the southern margin of the continental Shelf of the East China Sea.According to the data of subbottom profile the detail geological interpretations are as follows:①the high resolution subbottom profiles record the submarine topography,geomorphy and sedimentary structures of the study area directly,which can be used for studing the sedimentary environment and geolgical history;②three paleao-river valleys have been probed and it is shown that the shoreline of china Sea shelf in the umu galacial(Late Pleistocene Epoch) maybe was 150 m below the present sea levef;③ in this area,the complicated geomorophy and structures is related to the earthguake、volcanicity,and soon.
It is expounded the probing of the high resolution subbottom profile on the southern margin of the continental Shelf of the East China Sea.According to the data of subbottom profile the detail geological interpretations are as follows:①the high resolution subbottom profiles record the submarine topography,geomorphy and sedimentary structures of the study area directly,which can be used for studing the sedimentary environment and geolgical history;②three paleao-river valleys have been probed and it is shown that the shoreline of china Sea shelf in the umu galacial(Late Pleistocene Epoch) maybe was 150 m below the present sea levef;③ in this area,the complicated geomorophy and structures is related to the earthguake、volcanicity,and soon.
1999, 17(1): 89-94.
Abstract:
By studying the distribution characteristics, lithologic assemblages， core features,grain size analysis and seismic reflectance of skeleton sandstone of D Ⅲ interval in Chaxi area,it is regarded that the reservoir sandstones was mainly the result of turbidity and the turbidite measure was connected with the whole event of the fault controlling sag—Niudong fault origin,evolution and extinetion. There are three turbidity fan (Xionggul-Cha39,Cha76 and Cha107-Xiong21)in the area by analysis. Because of late differential compaction,they belong to three structural nose respectively and all have gained commercial oil and gas. For the Sake of increasing reserves and production,they are the best area for the roll-over exploration.
By studying the distribution characteristics, lithologic assemblages， core features,grain size analysis and seismic reflectance of skeleton sandstone of D Ⅲ interval in Chaxi area,it is regarded that the reservoir sandstones was mainly the result of turbidity and the turbidite measure was connected with the whole event of the fault controlling sag—Niudong fault origin,evolution and extinetion. There are three turbidity fan (Xionggul-Cha39,Cha76 and Cha107-Xiong21)in the area by analysis. Because of late differential compaction,they belong to three structural nose respectively and all have gained commercial oil and gas. For the Sake of increasing reserves and production,they are the best area for the roll-over exploration.
1999, 17(1): 106-111.
Abstract:
Biomarker of organic matter and isotopic composition of n-alkanes in saturated hydrocarbon have been researched,and major samples are selected from Triassic and Jurassic important source rock in Kuqa section.From results we can see that characteristics of biomarker and biological composition in transgressive member are different from non-transgressive member.With various organisms input, the types of organic matter have been changed in transgressive processes.Biomarker parameters of transgressive member have specific characteristics:Pr/Ph less than 1,higher abundance of steranes,abundance of C27 are similar to C29 stertane,tricyclic terpane with feature of C21＜C23＞C24 and isotopic composition of nalkanes enriched 12C. Mesozoic transgressive events have important significance on oil and gas resources of Tabie uplift area and Kuqa depression in Tarim basin.
Biomarker of organic matter and isotopic composition of n-alkanes in saturated hydrocarbon have been researched,and major samples are selected from Triassic and Jurassic important source rock in Kuqa section.From results we can see that characteristics of biomarker and biological composition in transgressive member are different from non-transgressive member.With various organisms input, the types of organic matter have been changed in transgressive processes.Biomarker parameters of transgressive member have specific characteristics:Pr/Ph less than 1,higher abundance of steranes,abundance of C27 are similar to C29 stertane,tricyclic terpane with feature of C21＜C23＞C24 and isotopic composition of nalkanes enriched 12C. Mesozoic transgressive events have important significance on oil and gas resources of Tabie uplift area and Kuqa depression in Tarim basin.
1999, 17(1): 127-129.
Abstract:
There are abundant benzothiophene series compounds in the product of the reaction of sulphur with β-carotene, and both thiophene and benzothiophene series compounds in the products of reactions of sulphur with saturate chain compounds, implying that benzothiophenes series were formed by the reaction of sulphur with thiophenes or the benzenes containning side chain. The relative contents of thiophene series and benzothiophene series may indicate the maturity: in the case of same sedimental environment, that the content of thiophenes is high and that of benzothiophenes is low,indicating the low maturity,conversely indicating the high maturity.
There are abundant benzothiophene series compounds in the product of the reaction of sulphur with β-carotene, and both thiophene and benzothiophene series compounds in the products of reactions of sulphur with saturate chain compounds, implying that benzothiophenes series were formed by the reaction of sulphur with thiophenes or the benzenes containning side chain. The relative contents of thiophene series and benzothiophene series may indicate the maturity: in the case of same sedimental environment, that the content of thiophenes is high and that of benzothiophenes is low,indicating the low maturity,conversely indicating the high maturity.
1999, 17(1): 136-140.
Abstract:
Distribution of gammacerane in some marine evapo ritic environments such as Michigan basin shows that gammacerane, a hy persaline biomarker, is not absolutely associated with hy persaline envi ronment ;Relative higher concent ration of g ammacerane in Song liao fresh-brackish lacustrine envi ronment is connected w ith water column stratification caused by event of linking between lacust rine and sea. Both stable carbon isotopic compositions of gammacerane and microbiology indicate that the formation of gammacerane is related to water column strat if ication.Since water columns in hypersaline depositional environments are of ten density st ratified, it explains w hy g ammacerane is of ten found in sediments deposi ted under hypersaline conditions but is not necessarily restricted in this type of deposits.
Distribution of gammacerane in some marine evapo ritic environments such as Michigan basin shows that gammacerane, a hy persaline biomarker, is not absolutely associated with hy persaline envi ronment ;Relative higher concent ration of g ammacerane in Song liao fresh-brackish lacustrine envi ronment is connected w ith water column stratification caused by event of linking between lacust rine and sea. Both stable carbon isotopic compositions of gammacerane and microbiology indicate that the formation of gammacerane is related to water column strat if ication.Since water columns in hypersaline depositional environments are of ten density st ratified, it explains w hy g ammacerane is of ten found in sediments deposi ted under hypersaline conditions but is not necessarily restricted in this type of deposits.
1999, 17(1): 145-148.
Abstract:
On the basis of linear correlation between loess sedimentation rate and grain size,a new method of establishment of loess sequence age was developed. In this method, we assume that there is a linear relationship between the loess sedimentation rate R and the grain size S at the same horizon in a loess sequence,that is, S=aR+b,where a and b are coefficients awaiting determination. Supposing that the loess between two time control points is divided into n layers.the depths of which are indicated by Δh1,Δh2......Δhn and the time Δt1,Δt2......Δtn,respectively,a system of equations can be established by proceeding. fi(Δt1,Δt2,......Δtn-1,Δtn,a,b)=0 i=1,2......n,n+1,n+2 in which Δt1,Δt2......Δtn,a and b are unknown numbers. As this is a system of special nonlinear algebraic equations,which consists of n+2 equations,its numerical solution will be obtained with a iteration method.In this way,we can carry out a transformation from depth to age for a loess sequence. As an example,the depth-age transformation in the Luochuan loess section
On the basis of linear correlation between loess sedimentation rate and grain size,a new method of establishment of loess sequence age was developed. In this method, we assume that there is a linear relationship between the loess sedimentation rate R and the grain size S at the same horizon in a loess sequence,that is, S=aR+b,where a and b are coefficients awaiting determination. Supposing that the loess between two time control points is divided into n layers.the depths of which are indicated by Δh1,Δh2......Δhn and the time Δt1,Δt2......Δtn,respectively,a system of equations can be established by proceeding. fi(Δt1,Δt2,......Δtn-1,Δtn,a,b)=0 i=1,2......n,n+1,n+2 in which Δt1,Δt2......Δtn,a and b are unknown numbers. As this is a system of special nonlinear algebraic equations,which consists of n+2 equations,its numerical solution will be obtained with a iteration method.In this way,we can carry out a transformation from depth to age for a loess sequence. As an example,the depth-age transformation in the Luochuan loess section
1999, 17(1): 156-160.
Abstract:
In this paper, ketone and alcohol lipid compounds in airborne particulates from Lanzhou city have been analy sed and studied.The concent rations of n-alkan-2-ones and n-alkanols are 20-270 ng.m-3 and 520-910 ng.m-3, respectively.They have higher concent rations in March than in July and August, which is related to special topog raphy and climate of Lanzhou area.The dist ribution of these compounds indicates that they are derived anthropogenic activity, microbes and modern higher plants and the assignment of their sources is 2.8 %～ 19.7 % fo r anthropogenic acitivity, 15.4 %～ 34.6 % for microbes and 50.3 %～ 81.8 % for modern higher plant s.Sterols are present at low concent rations,which are provided by modern organisms.The presence of abundant C18 isoprenoid ketone shows that org anic mat ter in airborne particulates f rom Lanzhou city is transformed in the oxidizing process of the atmosphre.
In this paper, ketone and alcohol lipid compounds in airborne particulates from Lanzhou city have been analy sed and studied.The concent rations of n-alkan-2-ones and n-alkanols are 20-270 ng.m-3 and 520-910 ng.m-3, respectively.They have higher concent rations in March than in July and August, which is related to special topog raphy and climate of Lanzhou area.The dist ribution of these compounds indicates that they are derived anthropogenic activity, microbes and modern higher plants and the assignment of their sources is 2.8 %～ 19.7 % fo r anthropogenic acitivity, 15.4 %～ 34.6 % for microbes and 50.3 %～ 81.8 % for modern higher plant s.Sterols are present at low concent rations,which are provided by modern organisms.The presence of abundant C18 isoprenoid ketone shows that org anic mat ter in airborne particulates f rom Lanzhou city is transformed in the oxidizing process of the atmosphre.
