1983 Vol. 1, No. 1
column
Display Method:
1983, 1(1): 5-26.
Abstract:
of the "Lithosphere" project, enquiries about "The palaeooceans that sunk、:ndermountain ranges”, were the prodominant subject among in vestigations regarding tilerole of e} olution of sedimeniarv basins. Thus, discussions on scdicnentalogical prob-lems were the prevaliing topics amidst geologists non-adays.
of the "Lithosphere" project, enquiries about "The palaeooceans that sunk、:ndermountain ranges”, were the prodominant subject among in vestigations regarding tilerole of e} olution of sedimeniarv basins. Thus, discussions on scdicnentalogical prob-lems were the prevaliing topics amidst geologists non-adays.
1983, 1(1): 42-49.
Abstract:
Oncoids occur abundantly in the calcarenite and the pelletal limestone in the lower part of the third limestone member from Yongxian formation of the upper Devonian in Siding, Guangxi. The content of the oncoids is about 15-30%. They are mostly elliptical bodies with diameters ranging from 0.5 to 2 cm, even up to 65 cm in maximum. On the basis of the microscopic study, they are all of algal origin. They are mainly of four species such as algae-Ortonell sp, Mitcheldeania sp, Rothopletzella sp and Lithophyllum sp. Four main types of internal laminae of the oncoids may be recognized: ( 1 ) micritic lamina, ( 2 ) grumose lamina, ( 3 ) organism-bearing lamina and ( 4 ) algal lamina. They were basically formed by micritic and algal lamina surrounding an intraclast or a bioclast, or by the interlayers of micritic, grumose and algal lamina surrounding a bioclast or an intraclast. According to the characteristics of the shapes,they may be divided into the cap-form, petal-form and subellipsoidal-form. The laminae of cap-form grew upward so as to pile up and those of petal-form grew irregularly. They were all formed into inconsecutive laminae.The laminae of subellipsoidal-form grew continuously. The growth of the laminae was controlled by the movement of water body. The algae always grew towards the sunshine. If the water body persisted in agitation and oncoids turned over continuously, the oncoids formed continuous laminae. If the water body agitated weakly and oncoids rested or turned over intermittently, the oncoids formed inconsecutive laminae. Thus the oncoids of cap-form and petal-form were formed in the environment of shallow water with weak agitation and low energy. The oncoids of subellipsoidal-form were formed in the environment of persistent agitation and high energy. Oncoids of cap-form and petal-form mainly occur in pelletal limestone and subellipsoidal-form ones occur in calcarenite.It is suggested that the environment of the formation of the oncoids coincided with that of accumulation.
Oncoids occur abundantly in the calcarenite and the pelletal limestone in the lower part of the third limestone member from Yongxian formation of the upper Devonian in Siding, Guangxi. The content of the oncoids is about 15-30%. They are mostly elliptical bodies with diameters ranging from 0.5 to 2 cm, even up to 65 cm in maximum. On the basis of the microscopic study, they are all of algal origin. They are mainly of four species such as algae-Ortonell sp, Mitcheldeania sp, Rothopletzella sp and Lithophyllum sp. Four main types of internal laminae of the oncoids may be recognized: ( 1 ) micritic lamina, ( 2 ) grumose lamina, ( 3 ) organism-bearing lamina and ( 4 ) algal lamina. They were basically formed by micritic and algal lamina surrounding an intraclast or a bioclast, or by the interlayers of micritic, grumose and algal lamina surrounding a bioclast or an intraclast. According to the characteristics of the shapes,they may be divided into the cap-form, petal-form and subellipsoidal-form. The laminae of cap-form grew upward so as to pile up and those of petal-form grew irregularly. They were all formed into inconsecutive laminae.The laminae of subellipsoidal-form grew continuously. The growth of the laminae was controlled by the movement of water body. The algae always grew towards the sunshine. If the water body persisted in agitation and oncoids turned over continuously, the oncoids formed continuous laminae. If the water body agitated weakly and oncoids rested or turned over intermittently, the oncoids formed inconsecutive laminae. Thus the oncoids of cap-form and petal-form were formed in the environment of shallow water with weak agitation and low energy. The oncoids of subellipsoidal-form were formed in the environment of persistent agitation and high energy. Oncoids of cap-form and petal-form mainly occur in pelletal limestone and subellipsoidal-form ones occur in calcarenite.It is suggested that the environment of the formation of the oncoids coincided with that of accumulation.
1983, 1(1): 63-74.
Abstract:
The total cardonate contents of the sediments in the East China Sea are abundant and widely distributed. The contents distribution and components vary with di-ffernt environmental conditions. It appears that among all the measured contents the contents of the outshore carbonate are greater than those of the near-coast carbonate and the contents of the southwestern area greater than those of the northwestern area, and the contents in the Okinawa Trough carbonate the greatest. The eomponents of the carbonate in the sediments of the East China Sea are mainly molluscan shell remains, foraminiferal scale and terrigenous fragmental carbonate etc. In the near coastal river mouth and inner continental shelf areas, there are mainly terrigenous fragmental carbonate, with a little bit of carbonate caused by chemical precipitation and biochemical processes. Also there are some organic remains. The carbonate in the outshore area is mainly made of the remains and newly growing organic skeleton. The maior chemical constituent in the sediments is caleium carbonate. This has been proved by the ratio and linear relation between carbonate and calcium contents. The mineral composition in carbonate is mainly calcite. As sea areas are different, the formation conditions of carbonate are also different. The carbonate in the near coastal river mouth area was formed mainly by the reprecipitation of the enomous terrigenous carbonate and acid carbonate carried by the Yangtze River. The biotic shells remains on the outershelf areas are the important source of carbonate, whereas in the outer shelf edge area and the Okinawa Trough, because the Kuroshio warm current passes through, the high temeprature, salinity and nutrients of the Kuroshoi current are suitable for organism, such as planktonic foraminifera, growing and breeding. After their death, their remains form a great quantity of deposits, which greatly increase the contents of carbonate. This results in a unique environment containing abundant organic carbonate. The distribution of carbonate in the East China Sea is closely related with the latitude, that is their contents decrease as the latitude increases. The conservational conditions of carbonate are also controlled by the factors of pH, water temperature, water pressure, hydrodynamic conditions and depositional rate etc. The East China Sea is in a weak alkaline environment and the temperature varies in a limited range. All these are favorable for the conservation of carbonate. The depositional rate is another important factor that affects the contents of carbonate. In the near coastal river mouth area with a high depositional rate, it is believed that the abundant terrigenous materials not only bury the carbonate forming organisms deeply, but also carry a large quantity of clay mtter which causes relatively less contents of carbonate than those in the areas of low depositional rate where the organic remains can continuously deposit at the surface.
The total cardonate contents of the sediments in the East China Sea are abundant and widely distributed. The contents distribution and components vary with di-ffernt environmental conditions. It appears that among all the measured contents the contents of the outshore carbonate are greater than those of the near-coast carbonate and the contents of the southwestern area greater than those of the northwestern area, and the contents in the Okinawa Trough carbonate the greatest. The eomponents of the carbonate in the sediments of the East China Sea are mainly molluscan shell remains, foraminiferal scale and terrigenous fragmental carbonate etc. In the near coastal river mouth and inner continental shelf areas, there are mainly terrigenous fragmental carbonate, with a little bit of carbonate caused by chemical precipitation and biochemical processes. Also there are some organic remains. The carbonate in the outshore area is mainly made of the remains and newly growing organic skeleton. The maior chemical constituent in the sediments is caleium carbonate. This has been proved by the ratio and linear relation between carbonate and calcium contents. The mineral composition in carbonate is mainly calcite. As sea areas are different, the formation conditions of carbonate are also different. The carbonate in the near coastal river mouth area was formed mainly by the reprecipitation of the enomous terrigenous carbonate and acid carbonate carried by the Yangtze River. The biotic shells remains on the outershelf areas are the important source of carbonate, whereas in the outer shelf edge area and the Okinawa Trough, because the Kuroshio warm current passes through, the high temeprature, salinity and nutrients of the Kuroshoi current are suitable for organism, such as planktonic foraminifera, growing and breeding. After their death, their remains form a great quantity of deposits, which greatly increase the contents of carbonate. This results in a unique environment containing abundant organic carbonate. The distribution of carbonate in the East China Sea is closely related with the latitude, that is their contents decrease as the latitude increases. The conservational conditions of carbonate are also controlled by the factors of pH, water temperature, water pressure, hydrodynamic conditions and depositional rate etc. The East China Sea is in a weak alkaline environment and the temperature varies in a limited range. All these are favorable for the conservation of carbonate. The depositional rate is another important factor that affects the contents of carbonate. In the near coastal river mouth area with a high depositional rate, it is believed that the abundant terrigenous materials not only bury the carbonate forming organisms deeply, but also carry a large quantity of clay mtter which causes relatively less contents of carbonate than those in the areas of low depositional rate where the organic remains can continuously deposit at the surface.
1983, 1(1): 86-95.
Abstract:
The upper Permiau of Guangxi may be divided into two formations: Heshan and Changxing, including four types of coal-bearing formation of carbonate; residuum, algae-flat, mixed tide flat and winnowed platform edge sands. A. The residuum coal-bearing formation is of transgressive facies sequence—the residuum—the lacustrine—the bog—the tide flat, which consists of fcrro-beau- xite—cmpholite clay—coal bed—carbonaceous algae limestone. It appears at the bottom of the Heshan formation. The thickness of coal bed is labile. B. The algae-flat coal-bearing formation is of regressive facies sequence—open marine platform—the algae flat—the algae-flat swamp and the littoral marsh— the algae flat, which consists of biomicrite—Gymnocodium limestone—coal bed —Gymnocodium limestone.Most of them expose at the upper of the Heshan formation. The thickness of coal bed is thinner and more stable. C, The mixed tide flat coal-bearing formation is of regressive facies sequence —the mixed tide flat—the swamp—the mud flat, which consists of calcareous sandstone, mid stone and sparry iron, intercalating marlite (containing palaeophyte) —coal bed—clay bed. The coal bed is more unstable. D. The edge sands coal-bearing formation is of the tide flat — the winnowed platform edge sands—the tide flat—the algae- flat swamp—the tide flat,which consists of calcarenite—carbonaceous algae limestone— bed—mierite spongia algae limestone. The coal bed is most unstable. This paper will discuss the incoalation model of algae-flat swamp, taking the coal bed of the apper Heshan formation in central Guangxi as an example. 1. Palacotectonic seitings. tings. The formation was formed on the stable settle platform. The E-W strecture piling in this area played an upward well-fed part. The platform acquired more stable subsidence. 2 . Palaeogeographic conditions. Three parts of this area were surrounded by land. The Xeifeng land ( North ) and the Daminshan old land ( South ) had got aged. The uplifting Yunkai old land ( East ) transported its terrigenous elastics into the sea. But they were sustained by the bathyal basin at the margin of the old land. Therefore the water was shallow and clear on the platform. when the climate was warm and full of sunshine, organism was thriving and the carbonate platform was formed rapidly. The other part of the platform was open to the sea. The water came in and out freely. With difference of relief, the facies change occurre 3 . The effect of algae. The algae, especially the Gymnocodium were dominant in the roof and bottom of coal bed. Sometimes they formed the algae limestone. That the Gymnocodium always intergrew with some of algae colloid foraminifera and ostracod showed shallow water circumstance. It is somewhat difficult to sort the clastic of organism and it was intact individually,sometimes it could be distinte-grated or broken. Their edge angles and less abrasion showed a lower energy and intermittent turbulent environment. After the depth of the Gymnocodium, most of them accumulated in situ,and spread to laminate on the floor. It is called the algae-flat. Accompanying the platform uplift, the Gymnocodium played an important role in the shallowing upward sequence. When the algae-flat rose above the low tide, the soil in which plants grew occurred. 4 . Coal-forming substances. In the past people did not know the origin that coal bed cored on the limestone. When the present mangrove ( eg. Rhizophoraceae ) plants are observed in the intertidal zone, the view that peat could be formed by mangrove-like plants is put forward. It is imaginable that the plants of late palaeozoic era could live in saline or brackish water. Later we noticed that the fossils of normal swamp were found on the roof of coal bed as well. Therefore, in the in-coalation process, the coal-forming plants of coal bed of Heshan formation were mangrove-like plants in the earlier stage, and normal swamp plants in the middle and later stages and this was a
The upper Permiau of Guangxi may be divided into two formations: Heshan and Changxing, including four types of coal-bearing formation of carbonate; residuum, algae-flat, mixed tide flat and winnowed platform edge sands. A. The residuum coal-bearing formation is of transgressive facies sequence—the residuum—the lacustrine—the bog—the tide flat, which consists of fcrro-beau- xite—cmpholite clay—coal bed—carbonaceous algae limestone. It appears at the bottom of the Heshan formation. The thickness of coal bed is labile. B. The algae-flat coal-bearing formation is of regressive facies sequence—open marine platform—the algae flat—the algae-flat swamp and the littoral marsh— the algae flat, which consists of biomicrite—Gymnocodium limestone—coal bed —Gymnocodium limestone.Most of them expose at the upper of the Heshan formation. The thickness of coal bed is thinner and more stable. C, The mixed tide flat coal-bearing formation is of regressive facies sequence —the mixed tide flat—the swamp—the mud flat, which consists of calcareous sandstone, mid stone and sparry iron, intercalating marlite (containing palaeophyte) —coal bed—clay bed. The coal bed is more unstable. D. The edge sands coal-bearing formation is of the tide flat — the winnowed platform edge sands—the tide flat—the algae- flat swamp—the tide flat,which consists of calcarenite—carbonaceous algae limestone— bed—mierite spongia algae limestone. The coal bed is most unstable. This paper will discuss the incoalation model of algae-flat swamp, taking the coal bed of the apper Heshan formation in central Guangxi as an example. 1. Palacotectonic seitings. tings. The formation was formed on the stable settle platform. The E-W strecture piling in this area played an upward well-fed part. The platform acquired more stable subsidence. 2 . Palaeogeographic conditions. Three parts of this area were surrounded by land. The Xeifeng land ( North ) and the Daminshan old land ( South ) had got aged. The uplifting Yunkai old land ( East ) transported its terrigenous elastics into the sea. But they were sustained by the bathyal basin at the margin of the old land. Therefore the water was shallow and clear on the platform. when the climate was warm and full of sunshine, organism was thriving and the carbonate platform was formed rapidly. The other part of the platform was open to the sea. The water came in and out freely. With difference of relief, the facies change occurre 3 . The effect of algae. The algae, especially the Gymnocodium were dominant in the roof and bottom of coal bed. Sometimes they formed the algae limestone. That the Gymnocodium always intergrew with some of algae colloid foraminifera and ostracod showed shallow water circumstance. It is somewhat difficult to sort the clastic of organism and it was intact individually,sometimes it could be distinte-grated or broken. Their edge angles and less abrasion showed a lower energy and intermittent turbulent environment. After the depth of the Gymnocodium, most of them accumulated in situ,and spread to laminate on the floor. It is called the algae-flat. Accompanying the platform uplift, the Gymnocodium played an important role in the shallowing upward sequence. When the algae-flat rose above the low tide, the soil in which plants grew occurred. 4 . Coal-forming substances. In the past people did not know the origin that coal bed cored on the limestone. When the present mangrove ( eg. Rhizophoraceae ) plants are observed in the intertidal zone, the view that peat could be formed by mangrove-like plants is put forward. It is imaginable that the plants of late palaeozoic era could live in saline or brackish water. Later we noticed that the fossils of normal swamp were found on the roof of coal bed as well. Therefore, in the in-coalation process, the coal-forming plants of coal bed of Heshan formation were mangrove-like plants in the earlier stage, and normal swamp plants in the middle and later stages and this was a
1983, 1(1): 107-117.
Abstract:
Sedimentary facies is the major control of petroleum origin, migration and distribution in terrestrial basins.The common study methods of sedimentary facies are based on the characteristics of sedimentary sequence and various markers such as rock facies, mineral facies, biological fossils, trace fossils, rock structure, etc.and they are classified by geochemical indicators.We have used GC-MS to analyze the samples of different sedimentary facies (swamp facies, littoral and shallow water lacustrine facies, subdeep-deep water lacustrine facies) of triterpanes and steranes in an attempt to find out the sedimentary facies indicators of biomarkers and their molecular parameters in terrestrial basins Sedimentary facies indicator of biomarkers is one of the means of measarement to study sedimentary facies on molecular level and it is also a complemental means to the conventional methods.In geological period,the biomarker compounds had more stable carbon skeleton, they transferred the informations of primary living organisms, and were closely related to biological bodies.The study of sedimentary facies of terrestrial basin shows that the type of organic matter in source rocks is controlled on the plane by the belts of the sedimentary facies.Land plants are mostly distributed on the lakeshore, whereas aquatic organisms at the central part of the lake.Therefore, the biomarkcrs used to recognize the type of organic matter and their molecular parameters may also be used as compounds of facies indicators of biomarkers. Different facies from lower Cretaceous Qingshankon 2-3 member of Songliao basin, and samples of different ages but in the same sedimentary facies from Pale-agene Shahejie formation of Bohai Bay basin, lower Cretaceous Qingshankon 2-3 member of Songliao basin, Jurassic Yunan formation of Erduosi basin have been analyzed by comparing and examining triterpanes and steranes from different sedimentary facies along with geological and geochemical data, and therefore we have got some knowledge about sedimentary facies indicators of biomarkers of the terrestrial basin. Based on the study of biomarker in sedimentary facies belts from the basins,we have suggested that oleanane, C29-hopane/C30-hopane, Tm/TS,ΣC27 + C29-hopane/Σ C30-hopanes andΣC27-steranes/Σ C29-steranes, 4 -methyl-C29-steranes/5α-C27-ster-anes can be used as indicators of the biomarkers and molecular parameters. By using geochemical parameters, the sedimentary facies bands may be classified as follows: The swamp facies,in general,contain oleanane and C29-hopane/C30-hopane, Tm/TS, Σ C27+C29/Σ C30 are higher, while in steranes Σ C27/Σ C29 is relatively lower but the 4 -methyl-C29/5α-C27 higher.The characteristics of subdeep-deep lacustrine facies is contrary to the previous discussion.The lakeshore facies are moderate in characteristics of the two mentioned above. The authors believe that better results can be acheivcd if facies indicators of biomarkers and their molecular parameters are used to classify the sedimentary facies in company with geological and geochemical parameters.The biomarkers and their parameters suggested in this paper have shown their applicability to the samples studied.
Sedimentary facies is the major control of petroleum origin, migration and distribution in terrestrial basins.The common study methods of sedimentary facies are based on the characteristics of sedimentary sequence and various markers such as rock facies, mineral facies, biological fossils, trace fossils, rock structure, etc.and they are classified by geochemical indicators.We have used GC-MS to analyze the samples of different sedimentary facies (swamp facies, littoral and shallow water lacustrine facies, subdeep-deep water lacustrine facies) of triterpanes and steranes in an attempt to find out the sedimentary facies indicators of biomarkers and their molecular parameters in terrestrial basins Sedimentary facies indicator of biomarkers is one of the means of measarement to study sedimentary facies on molecular level and it is also a complemental means to the conventional methods.In geological period,the biomarker compounds had more stable carbon skeleton, they transferred the informations of primary living organisms, and were closely related to biological bodies.The study of sedimentary facies of terrestrial basin shows that the type of organic matter in source rocks is controlled on the plane by the belts of the sedimentary facies.Land plants are mostly distributed on the lakeshore, whereas aquatic organisms at the central part of the lake.Therefore, the biomarkcrs used to recognize the type of organic matter and their molecular parameters may also be used as compounds of facies indicators of biomarkers. Different facies from lower Cretaceous Qingshankon 2-3 member of Songliao basin, and samples of different ages but in the same sedimentary facies from Pale-agene Shahejie formation of Bohai Bay basin, lower Cretaceous Qingshankon 2-3 member of Songliao basin, Jurassic Yunan formation of Erduosi basin have been analyzed by comparing and examining triterpanes and steranes from different sedimentary facies along with geological and geochemical data, and therefore we have got some knowledge about sedimentary facies indicators of biomarkers of the terrestrial basin. Based on the study of biomarker in sedimentary facies belts from the basins,we have suggested that oleanane, C29-hopane/C30-hopane, Tm/TS,ΣC27 + C29-hopane/Σ C30-hopanes andΣC27-steranes/Σ C29-steranes, 4 -methyl-C29-steranes/5α-C27-ster-anes can be used as indicators of the biomarkers and molecular parameters. By using geochemical parameters, the sedimentary facies bands may be classified as follows: The swamp facies,in general,contain oleanane and C29-hopane/C30-hopane, Tm/TS, Σ C27+C29/Σ C30 are higher, while in steranes Σ C27/Σ C29 is relatively lower but the 4 -methyl-C29/5α-C27 higher.The characteristics of subdeep-deep lacustrine facies is contrary to the previous discussion.The lakeshore facies are moderate in characteristics of the two mentioned above. The authors believe that better results can be acheivcd if facies indicators of biomarkers and their molecular parameters are used to classify the sedimentary facies in company with geological and geochemical parameters.The biomarkers and their parameters suggested in this paper have shown their applicability to the samples studied.
1983, 1(1): 129-136.
Abstract:
This paper points out that expanding clay minerals can absorb uranium and gives a list of clay minerals with rich or poor uranium occuring in structural fracture zone.And characteristics of the clay minerals are described by means of electron microscope and various analyses such as differential thermal analysis, infrared absorbed spectral analysis, x-ray diffraction and chemical analysis.The conclusion is that the uranium content in the regular interstratified chlorite-montmorillonite mineral is the highest, even up to 0.246%.The main mineral,montmorillonite, plays an important role in absorbing uranium.The experiment data indicate that under the same conditions Na-montmorillonite absorbs more uranium than Ca-montmorillonitc. The mechanism of uranium absorption is, described as follows. The montmorillon-ites are characterized by ion-change ability and absorbing water, which can offer fasorable condition for uranuly ( UO ) moving into structural layers.In addition, because of the fine grain of the montmorillonites and their large sarface area they can absorb more uranium .Furthcrmore, the environment in which monimerillonites occur is favorable for uranium accumulation.
This paper points out that expanding clay minerals can absorb uranium and gives a list of clay minerals with rich or poor uranium occuring in structural fracture zone.And characteristics of the clay minerals are described by means of electron microscope and various analyses such as differential thermal analysis, infrared absorbed spectral analysis, x-ray diffraction and chemical analysis.The conclusion is that the uranium content in the regular interstratified chlorite-montmorillonite mineral is the highest, even up to 0.246%.The main mineral,montmorillonite, plays an important role in absorbing uranium.The experiment data indicate that under the same conditions Na-montmorillonite absorbs more uranium than Ca-montmorillonitc. The mechanism of uranium absorption is, described as follows. The montmorillon-ites are characterized by ion-change ability and absorbing water, which can offer fasorable condition for uranuly ( UO ) moving into structural layers.In addition, because of the fine grain of the montmorillonites and their large sarface area they can absorb more uranium .Furthcrmore, the environment in which monimerillonites occur is favorable for uranium accumulation.
1983, 1(1): 27-41.
Abstract:
logy were in almost ever- respects. It is under this blessingatmosphere, the AC-TA SEDIIIIE\TOLOGICASI\ICA" Were given birth.
logy were in almost ever- respects. It is under this blessingatmosphere, the AC-TA SEDIIIIE\TOLOGICASI\ICA" Were given birth.
1983, 1(1): 50-62.
Abstract:
Fuxian Lake is situated in the east of Yunnan Plateau. It is a lake of thegraben or intermontane type with fault blocks and scarps prevailing in its neighbour-hood, Its area covers 211 km2, and its maximum depth reaches 155 m with itsmean 89 m. Only minor rivulets run into the lake. The slopes of the lakeshore zone are,generally, rather abrupt, Floods containing a large amount of detritus swiftly flowinto the lake in rainy season. Its deposit characterizes lake basin sediment of grab-en type. On the plane, the deposits are distributed from the highenergy zone oflake-shore to the low-enery zone of deep-lake and their grain size is from coarse tofine, Both the belts of lakeshore gravel and shallow-lake sand-silt are comparativelynarrow, The water of sand-silt belt is generally deep up to 10-20 m, and the centralpart of the lake with muddy sediments covers 85% of the whole lacustrine area, The frequency curve of lakeshore deposits is of polykurtosis, Its grain size ran-ge is very wide, aФ-about 2.5, SK> 0;the cumulative curve presents an irregulararc, deposits mainly concentrate on the coarse end of the curve; traction popula-tion shows dominant in both log-probability plot and C/M diagram, which indicatescoarser grains and poor sorting, The frequency curves of shallow-lake deposits are strongly bimodal and the mainpeak of grain size concentrates on 3-5Ф, it shows that the deposits are mainly ma-de of silt and sand which contain mud, aФ-2 to3 ,skewaess being positives the pro-bability plot reflects that the deposits move in the way of saltation and suspensionor hypersaltatioas in the C/M pattern the range of grain size is wider, which indi-Gates the great differentiation of sorting, The kurtosis of the deep-lake deposits has a single peak, the grains are coarser than4Ф, and their main peak concentrates on 8一9小.It illustrates that all the depositsconsist of suspension population二ith QФof 1.5 to 2.0 and ske wness being negativeprobability plot has three log-normal segments, which represent coarse-silt, fine-si-It and clap respectively. The position of their junction correspondingly shifts towa-rds fine size with the increasing depth of watery the C/M diagram corresponds to the sedimentary area of suspension of the deep-sea, The turbidite deposits in the northern deep-lake are deposits of density flov-striggered by slumping and moving downslope, the grain size is coarser than that ofother deep-lake sediments, The vertical section of turbidite deposits is interbedding of sand,'mud with flyschfeature.The monocy-clic bed from the lower to the upper is moderate fine sand contain-ing gravel, silt-sand and clay in turn, w hick reflects the feature of graded bedding, The cyclic bottom is obviously- separated from underlying clay bed, The kurtos-is of the turbidite deposits is not obwious, and the grain sire range is v-ider infrequency cvarve; the probability plot in a straight line has a lo",c slope, indicatingpoor sorting; the position of points on Ci'\I diagram corresponds to the grabed su-speusion deposits, C/M pattern in long belt shape is parallel to C=M straight line. In other deep-lake areas, the sediment sections shoR isotropic clan, In this article the grain size data on 260 samplesare adopted. These samples were collected from the bottom of the lake, the core and partly from the lakeshore,among them the coarse ones are analyzed with sieve analysis and those fine-grainedones of 4.38Фare determined by automatic particle size distribution determinationappartus(Type RS-11)after being given separation treatment with supersonic wa-ve. mloreover, statistical parameters should be made to the grain size data with mo-went measure.
Fuxian Lake is situated in the east of Yunnan Plateau. It is a lake of thegraben or intermontane type with fault blocks and scarps prevailing in its neighbour-hood, Its area covers 211 km2, and its maximum depth reaches 155 m with itsmean 89 m. Only minor rivulets run into the lake. The slopes of the lakeshore zone are,generally, rather abrupt, Floods containing a large amount of detritus swiftly flowinto the lake in rainy season. Its deposit characterizes lake basin sediment of grab-en type. On the plane, the deposits are distributed from the highenergy zone oflake-shore to the low-enery zone of deep-lake and their grain size is from coarse tofine, Both the belts of lakeshore gravel and shallow-lake sand-silt are comparativelynarrow, The water of sand-silt belt is generally deep up to 10-20 m, and the centralpart of the lake with muddy sediments covers 85% of the whole lacustrine area, The frequency curve of lakeshore deposits is of polykurtosis, Its grain size ran-ge is very wide, aФ-about 2.5, SK> 0;the cumulative curve presents an irregulararc, deposits mainly concentrate on the coarse end of the curve; traction popula-tion shows dominant in both log-probability plot and C/M diagram, which indicatescoarser grains and poor sorting, The frequency curves of shallow-lake deposits are strongly bimodal and the mainpeak of grain size concentrates on 3-5Ф, it shows that the deposits are mainly ma-de of silt and sand which contain mud, aФ-2 to3 ,skewaess being positives the pro-bability plot reflects that the deposits move in the way of saltation and suspensionor hypersaltatioas in the C/M pattern the range of grain size is wider, which indi-Gates the great differentiation of sorting, The kurtosis of the deep-lake deposits has a single peak, the grains are coarser than4Ф, and their main peak concentrates on 8一9小.It illustrates that all the depositsconsist of suspension population二ith QФof 1.5 to 2.0 and ske wness being negativeprobability plot has three log-normal segments, which represent coarse-silt, fine-si-It and clap respectively. The position of their junction correspondingly shifts towa-rds fine size with the increasing depth of watery the C/M diagram corresponds to the sedimentary area of suspension of the deep-sea, The turbidite deposits in the northern deep-lake are deposits of density flov-striggered by slumping and moving downslope, the grain size is coarser than that ofother deep-lake sediments, The vertical section of turbidite deposits is interbedding of sand,'mud with flyschfeature.The monocy-clic bed from the lower to the upper is moderate fine sand contain-ing gravel, silt-sand and clay in turn, w hick reflects the feature of graded bedding, The cyclic bottom is obviously- separated from underlying clay bed, The kurtos-is of the turbidite deposits is not obwious, and the grain sire range is v-ider infrequency cvarve; the probability plot in a straight line has a lo",c slope, indicatingpoor sorting; the position of points on Ci'\I diagram corresponds to the grabed su-speusion deposits, C/M pattern in long belt shape is parallel to C=M straight line. In other deep-lake areas, the sediment sections shoR isotropic clan, In this article the grain size data on 260 samplesare adopted. These samples were collected from the bottom of the lake, the core and partly from the lakeshore,among them the coarse ones are analyzed with sieve analysis and those fine-grainedones of 4.38Фare determined by automatic particle size distribution determinationappartus(Type RS-11)after being given separation treatment with supersonic wa-ve. mloreover, statistical parameters should be made to the grain size data with mo-went measure.
1983, 1(1): 75-85.
Abstract:
The problems of preservation and conversion of organic substances in sedimentary regions of present water spheres, oil pools as well as coal mines were discussed with respect to energy flows, food chains of microbial ecosystems and microbiological processes of C.N.S. cycles at the same time changes of C/N in present sediments were also described in detail. It has been pointed out that in aerobic conditions, organic substances can not be preserved because microogranisms mineralize them into CO2. In anaerobic conditions, when microorganisms consume organic substances, in addition to CO2, small molecular organic and reduced inorganic products are produced. Energy is stored in them, which results in a more complex process of substance and energy conversion than that under the former condition. But both aerobic and anaerobic are present in today's sediments. ( 1 ) The range of energy source substance available for microorganisms is reduced with the decrease of oxidative abilities of electron accepters O2, NO3, SO4 and C02, thus the range and the amount of organic substance to be consumed by microorganisms become limited. It follows that food chain ( or food net ) turns more complex, which helps preserve a large amount of organic substance. ( 2 ) Energy produced by metabolates in anaerobic microorganisms, is partially transferred to sediments so as to absorb O2 and to create reduced phase, which is favourable for the preservation of organic substance. The mechanisms as mentioned above have been dealt with in detail and some instances were taken to explain the relationships and the reaction levels between microorganisms and energy conversions. In short, the types, the enriched levels of organic substances and O2 volume are the key factors for the preservation of organic substance. In addition, some microbial genus and species in oil pools and coal mines, and their roles in substance and energy conversions as well as necessary ecological conditions have also been described.
The problems of preservation and conversion of organic substances in sedimentary regions of present water spheres, oil pools as well as coal mines were discussed with respect to energy flows, food chains of microbial ecosystems and microbiological processes of C.N.S. cycles at the same time changes of C/N in present sediments were also described in detail. It has been pointed out that in aerobic conditions, organic substances can not be preserved because microogranisms mineralize them into CO2. In anaerobic conditions, when microorganisms consume organic substances, in addition to CO2, small molecular organic and reduced inorganic products are produced. Energy is stored in them, which results in a more complex process of substance and energy conversion than that under the former condition. But both aerobic and anaerobic are present in today's sediments. ( 1 ) The range of energy source substance available for microorganisms is reduced with the decrease of oxidative abilities of electron accepters O2, NO3, SO4 and C02, thus the range and the amount of organic substance to be consumed by microorganisms become limited. It follows that food chain ( or food net ) turns more complex, which helps preserve a large amount of organic substance. ( 2 ) Energy produced by metabolates in anaerobic microorganisms, is partially transferred to sediments so as to absorb O2 and to create reduced phase, which is favourable for the preservation of organic substance. The mechanisms as mentioned above have been dealt with in detail and some instances were taken to explain the relationships and the reaction levels between microorganisms and energy conversions. In short, the types, the enriched levels of organic substances and O2 volume are the key factors for the preservation of organic substance. In addition, some microbial genus and species in oil pools and coal mines, and their roles in substance and energy conversions as well as necessary ecological conditions have also been described.
1983, 1(1): 96-106.
Abstract:
Monoaromatic sterane could be separated as biomarkers with basic peaks of m/c 239, m/e 253 and m/e 267 from aromatic hydrocarbon in bitumen extracts of source rocks or crude oil.Using GC/MS technology,monoaromatic sterane could be identified and its distribution characteristics could be obtained.By monoaromatic sterane we may correlate oil-oil or oil-source rocks,and evaluate their maturity.It is necessary to regard monoaromatic sterane as an additional parameter io steranes and terpancs. particularly for those samples with higher maturity and lower strength of sterenc and terpane. In the present report, purer monoarometic storanes have boon separated by col-amn chromategnaphy.Absorbers are 3 H2O- Al2O3 ( acid ) and fine H2O content ) , their weight ratio 8:1. This report presents some mass spectrograms and mass chromatograms, and dis-casses the characteristics of monoaromatic sterane mass spectrogram and the strn-cture, distribution characteristics and the source of monoaromatic steranes.Three scries of monoaromatic sterane with basic peaks of m/e 239, m/e 253 and m/e 267 respectively, have been identified, which are from nonmarine crude oils of one oilfield at home.The relative strength of all monoaromatic sterane fragment ions and molecular ions are quite low except the basic peaks.It means that monoaromatic sterane hydrocarbon framework is stable, and carbon-carbon bond crackings are mainly in side chains.For this crude oil, C ring is just the aromatic ring of mono-aromatic steranc.It is proved by mass spectrogram that three identified fragment ions of alkylbenzene, namely m/e 91, m/e 105 and m/e 119, are obviously present. It shows the existence of an aromatic ring.The position of the aromatic ring depends upon whether there are the fragment ions of m/e 145, m/e 159 and m/e 173 or not.As these fragment ions are not present on mass spectrogram, there is no tetra- line ring structure. Then we can exclude the possibility of B or A ring as an aromatic ring.Anyhow C ring is just the aromatic ring.Each of the three series of mon-oaromatic sterane of this crude oil has one or two or three methyl on A or B or C ring.The structure of monoaromatic sterane could be drawn from the above description (refer to figures ) .By mass chromatogram, these three series of monoaromatic sternne are divided into two groups of compounds with low or high carbon number respectively due to the fact that they have undergone different heat evolution periods. Taking account of the monoaromatic steranc with sterane and terpane parameters, this report correlates some oil sources and evaluate the maturity of one section.The mass chromatogram shows that there is relationship between Jing No.16 crude oil and An No.29 source rock. Similar is not only their distribution characteristics.but also all of their parameters.It proves that crude oil of ES3 of this well is from ES3 source rock.We have made monoaromatic sterane identification for four nonmarine source rocks in different depths of lower Cretaceous in a basin in the north of China, and discussed the heat evolution regularity, too.It is found that the relative content of monoaromatic sterane with low carbon number increases gradually along with depth, while that with high carbon number decreases.It shows that the low carbon number monoaromatic steranc is stable and high carbon number monoatic sterane urstab1e. And the latter is converted into low carbon numberarom with the depth. So the relative ratio of low carbon number could become the .
Monoaromatic sterane could be separated as biomarkers with basic peaks of m/c 239, m/e 253 and m/e 267 from aromatic hydrocarbon in bitumen extracts of source rocks or crude oil.Using GC/MS technology,monoaromatic sterane could be identified and its distribution characteristics could be obtained.By monoaromatic sterane we may correlate oil-oil or oil-source rocks,and evaluate their maturity.It is necessary to regard monoaromatic sterane as an additional parameter io steranes and terpancs. particularly for those samples with higher maturity and lower strength of sterenc and terpane. In the present report, purer monoarometic storanes have boon separated by col-amn chromategnaphy.Absorbers are 3 H2O- Al2O3 ( acid ) and fine H2O content ) , their weight ratio 8:1. This report presents some mass spectrograms and mass chromatograms, and dis-casses the characteristics of monoaromatic sterane mass spectrogram and the strn-cture, distribution characteristics and the source of monoaromatic steranes.Three scries of monoaromatic sterane with basic peaks of m/e 239, m/e 253 and m/e 267 respectively, have been identified, which are from nonmarine crude oils of one oilfield at home.The relative strength of all monoaromatic sterane fragment ions and molecular ions are quite low except the basic peaks.It means that monoaromatic sterane hydrocarbon framework is stable, and carbon-carbon bond crackings are mainly in side chains.For this crude oil, C ring is just the aromatic ring of mono-aromatic steranc.It is proved by mass spectrogram that three identified fragment ions of alkylbenzene, namely m/e 91, m/e 105 and m/e 119, are obviously present. It shows the existence of an aromatic ring.The position of the aromatic ring depends upon whether there are the fragment ions of m/e 145, m/e 159 and m/e 173 or not.As these fragment ions are not present on mass spectrogram, there is no tetra- line ring structure. Then we can exclude the possibility of B or A ring as an aromatic ring.Anyhow C ring is just the aromatic ring.Each of the three series of mon-oaromatic sterane of this crude oil has one or two or three methyl on A or B or C ring.The structure of monoaromatic sterane could be drawn from the above description (refer to figures ) .By mass chromatogram, these three series of monoaromatic sternne are divided into two groups of compounds with low or high carbon number respectively due to the fact that they have undergone different heat evolution periods. Taking account of the monoaromatic steranc with sterane and terpane parameters, this report correlates some oil sources and evaluate the maturity of one section.The mass chromatogram shows that there is relationship between Jing No.16 crude oil and An No.29 source rock. Similar is not only their distribution characteristics.but also all of their parameters.It proves that crude oil of ES3 of this well is from ES3 source rock.We have made monoaromatic sterane identification for four nonmarine source rocks in different depths of lower Cretaceous in a basin in the north of China, and discussed the heat evolution regularity, too.It is found that the relative content of monoaromatic sterane with low carbon number increases gradually along with depth, while that with high carbon number decreases.It shows that the low carbon number monoaromatic steranc is stable and high carbon number monoatic sterane urstab1e. And the latter is converted into low carbon numberarom with the depth. So the relative ratio of low carbon number could become the .
1983, 1(1): 118-128.
Abstract:
A systematic artificial simulative experiment of mature evolution was carried out with a piece of immature source rock from Naopocao No, 13-15 at Dongying seg. The sample underwent the treatment in an autoclave without chloroform extract.By using the reflectivity of the vitrite as a scale, experimental data can be converted into the corresponding formation depth of this area.As compared with the section of natural evolution, they appear very similar. The zones of petroleum generation can be divided by means of simulative experiment of the nature evolution process of artificial organic matters. ES3-4low mature oil generation zones at Dongying seg are 2200-3020 m deep, whereas mature zones 3020-3980 m.This is the highest stage with respect to oil generation.High mature zones are 3980-4950 m.The total depth of petroleum generation is 2750 m.In the depth over 4950 m, condensed oil and wet gas are expected to be found. By means of the heat pressure simulative experiment, we can obtain the oil generation amount at each evolution stage of different kinds of immature source rock,and subsequently, we can make drawings of oil generation amount of different organic facies.So long as we measure the reflectivity value of vitrite of kerogen of source rock at different depths of the stratum in pre-measured area and work out the diagram of the relationship between the reflectivity and the depth of vitrite in the study region, we shall be able to select the appropriate drawing of the amount of oil generation amount of a proper organic facies and find out the amount.
A systematic artificial simulative experiment of mature evolution was carried out with a piece of immature source rock from Naopocao No, 13-15 at Dongying seg. The sample underwent the treatment in an autoclave without chloroform extract.By using the reflectivity of the vitrite as a scale, experimental data can be converted into the corresponding formation depth of this area.As compared with the section of natural evolution, they appear very similar. The zones of petroleum generation can be divided by means of simulative experiment of the nature evolution process of artificial organic matters. ES3-4low mature oil generation zones at Dongying seg are 2200-3020 m deep, whereas mature zones 3020-3980 m.This is the highest stage with respect to oil generation.High mature zones are 3980-4950 m.The total depth of petroleum generation is 2750 m.In the depth over 4950 m, condensed oil and wet gas are expected to be found. By means of the heat pressure simulative experiment, we can obtain the oil generation amount at each evolution stage of different kinds of immature source rock,and subsequently, we can make drawings of oil generation amount of different organic facies.So long as we measure the reflectivity value of vitrite of kerogen of source rock at different depths of the stratum in pre-measured area and work out the diagram of the relationship between the reflectivity and the depth of vitrite in the study region, we shall be able to select the appropriate drawing of the amount of oil generation amount of a proper organic facies and find out the amount.
