1992 Vol. 10, No. 1
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Display Method:
1992, 10(1): 1-10.
Abstract:
Most of the bauxites (98%) in China are palaeoresiduum (old-weathered crust) facies bauxite, more than 80% of which is carboniferous and 19% Permian. Early Carboniferous palaeoresiduum facies bauxite dietribute in the Upper Yangtz palaeo-continent and Lanzhou-Xining palaeo-continent (Fig. 1) There are four subfacies in the Yangtz ( Fig. 2), and one in Lanzhou-Xining. Last Carboniferous palaeoresiduum facies bauxite distribute in North-China palaeo-continent with three subfacies (Fig.5) and the weatern margin of Tarim palaeo-continent (Fig.3) with one subfacies.The texture and structure of the bauxite ores, such as clastes. conglomerates, boulders and pisolites, oolites, nodules, concretions have the features of weathering and different from those sedimented in water bodies.There are no authigenic minerals and fossiles of hydrobios.Thus, it can be deduced that the ores are palaeoresiduum facies bauxite, and all of which where made of residual bauxite sabetance (laterite bauxite). On the palaeo- continents, autochthonous residure subfacies bauxite, distributed around the drainage divide; Near the drainage divide of the old allochthonous accumulated subfacies bauxite and / or fresh or saline water sedimented subfacies bauxite distributed near the sea shore; and between them was the meta- autochthenous accumulated subfacies bauxite (Fig.2).All of the residual bauxite subfacies were formed under meteovic conditions.As for the traneportation of residual bauxijic substances, it can be subdivided into dry ransporlation and wet transportation on the palaeocontinent, the former wae transportated by monsoon gravity in arid season, and the later was wet traneportaled as densive flow by runoff in rainy season.
Most of the bauxites (98%) in China are palaeoresiduum (old-weathered crust) facies bauxite, more than 80% of which is carboniferous and 19% Permian. Early Carboniferous palaeoresiduum facies bauxite dietribute in the Upper Yangtz palaeo-continent and Lanzhou-Xining palaeo-continent (Fig. 1) There are four subfacies in the Yangtz ( Fig. 2), and one in Lanzhou-Xining. Last Carboniferous palaeoresiduum facies bauxite distribute in North-China palaeo-continent with three subfacies (Fig.5) and the weatern margin of Tarim palaeo-continent (Fig.3) with one subfacies.The texture and structure of the bauxite ores, such as clastes. conglomerates, boulders and pisolites, oolites, nodules, concretions have the features of weathering and different from those sedimented in water bodies.There are no authigenic minerals and fossiles of hydrobios.Thus, it can be deduced that the ores are palaeoresiduum facies bauxite, and all of which where made of residual bauxite sabetance (laterite bauxite). On the palaeo- continents, autochthonous residure subfacies bauxite, distributed around the drainage divide; Near the drainage divide of the old allochthonous accumulated subfacies bauxite and / or fresh or saline water sedimented subfacies bauxite distributed near the sea shore; and between them was the meta- autochthenous accumulated subfacies bauxite (Fig.2).All of the residual bauxite subfacies were formed under meteovic conditions.As for the traneportation of residual bauxijic substances, it can be subdivided into dry ransporlation and wet transportation on the palaeocontinent, the former wae transportated by monsoon gravity in arid season, and the later was wet traneportaled as densive flow by runoff in rainy season.
1992, 10(1): 19-26.
Abstract:
The rapidly development of event stratigraphy in the past decades strengthen the concept that thestratigraphical record is coined by rare and short-term catastrophic events rather that by "fair weather"con-ditions.The authors focus cn。kind of high-energy events and their geological records, i. e.，the seisnncdeposites ur mute correctly specifical sedimentary structures caused by earthquake. Here is an example in the Upper Jurassic non-marine deposites IProm Emei County Sichuan Provincein which five sedimentary horizons with characteristic sedimentary structures are well developed and arethought to have been produced by seismic events.They are from the bottom to top: 1. undisturbed bed: lamination is left undeformed, while microfaults may be present in the beds at adistance of a few centimeters. 2.microfault bed: three microfaults can be recognized in the section of 2.8 meter long and they are allnormal fault. the thickness of this bed is about 15-30cm. 3.pleated bed: 6-27 cm thick folded lamination is quite clear in this horizon and a recumbent fold canbe seen at the left side of the section. 4.rubble bed: it is characterised by smaller fragments of the original sediments which were broken topieces by earthquake shock and seperated in the soupy matrix with vairying orientations.The thickness of thisbed is 16-28cm. 5.homogenized (soupy) bed: there are no laminations in this uppermost bed.It implies that a kind ofliquefaction caused by seismic shock may have destroyed all the strucl,ures of the uppermost layer.
The rapidly development of event stratigraphy in the past decades strengthen the concept that thestratigraphical record is coined by rare and short-term catastrophic events rather that by "fair weather"con-ditions.The authors focus cn。kind of high-energy events and their geological records, i. e.，the seisnncdeposites ur mute correctly specifical sedimentary structures caused by earthquake. Here is an example in the Upper Jurassic non-marine deposites IProm Emei County Sichuan Provincein which five sedimentary horizons with characteristic sedimentary structures are well developed and arethought to have been produced by seismic events.They are from the bottom to top: 1. undisturbed bed: lamination is left undeformed, while microfaults may be present in the beds at adistance of a few centimeters. 2.microfault bed: three microfaults can be recognized in the section of 2.8 meter long and they are allnormal fault. the thickness of this bed is about 15-30cm. 3.pleated bed: 6-27 cm thick folded lamination is quite clear in this horizon and a recumbent fold canbe seen at the left side of the section. 4.rubble bed: it is characterised by smaller fragments of the original sediments which were broken topieces by earthquake shock and seperated in the soupy matrix with vairying orientations.The thickness of thisbed is 16-28cm. 5.homogenized (soupy) bed: there are no laminations in this uppermost bed.It implies that a kind ofliquefaction caused by seismic shock may have destroyed all the strucl,ures of the uppermost layer.
1992, 10(1): 36-46.
Abstract:
The skeletons of organisms display many occurrence models which may be used to better understand the sedimentary environments within which they occur. After organisms died, the bodies, which deposit in the various depositional environments, will suffer different kinds of physical and chemical influence. Thus, the skeletons of organisms will be stamped the signs of depositional environments. The preservation patterns and types of fossils can be used as the tools to reconstruction of ancient depositional environments. The comparative taphonomy and taphofacies are new geological theories using fossil preservation patterns and types to rebuild ancient depositional environments. For this purpose, Speyer and Brett (1988) have established seven taphofacies for the late Paleozoic fossils, according to the skeletons biostratinomy which include intact transport of skeletons, disarticulation, fragment of skeletons and corrasion of skeletons. And, the taphofacies models corroborated by empirical data from Paleozoic strata, illustrate the distribution of taphonomic properties with respact to environmental energy, background sedimentation rate, and sediment oxygenation, according to Speyer Brett. Thus, these theories have bright future, but there still have some must be developed, and some questions and problems sould be answered and solved, espacially taphofacies theory. First, for taphofacies, only the simple models have been illustrated which suitable for the depositional margin environments of the continental shelves whthin which the fossils preserved in. But during the geological time, there were many different depositional environments, not only depositional margin environments, but also many sharpy bypass margin environments distributed all over the world. For example, there are many late Paleozoic bypass margins with very sharp slopes within the area of southern China, which unsuitable for Speyer's Taphofacies theory. Second, how to establish taphofacies which can be used in turbidites and storm deposits and used in fresh water depositional environments. The fresh water environments are very different with the ocean environments, therefore, the fossil preservation types in the fresh water depositional environments also show different characteristic. Although the theories still have shortage, they provide information important in paleoecological studies and rebuild depositional environments.
The skeletons of organisms display many occurrence models which may be used to better understand the sedimentary environments within which they occur. After organisms died, the bodies, which deposit in the various depositional environments, will suffer different kinds of physical and chemical influence. Thus, the skeletons of organisms will be stamped the signs of depositional environments. The preservation patterns and types of fossils can be used as the tools to reconstruction of ancient depositional environments. The comparative taphonomy and taphofacies are new geological theories using fossil preservation patterns and types to rebuild ancient depositional environments. For this purpose, Speyer and Brett (1988) have established seven taphofacies for the late Paleozoic fossils, according to the skeletons biostratinomy which include intact transport of skeletons, disarticulation, fragment of skeletons and corrasion of skeletons. And, the taphofacies models corroborated by empirical data from Paleozoic strata, illustrate the distribution of taphonomic properties with respact to environmental energy, background sedimentation rate, and sediment oxygenation, according to Speyer Brett. Thus, these theories have bright future, but there still have some must be developed, and some questions and problems sould be answered and solved, espacially taphofacies theory. First, for taphofacies, only the simple models have been illustrated which suitable for the depositional margin environments of the continental shelves whthin which the fossils preserved in. But during the geological time, there were many different depositional environments, not only depositional margin environments, but also many sharpy bypass margin environments distributed all over the world. For example, there are many late Paleozoic bypass margins with very sharp slopes within the area of southern China, which unsuitable for Speyer's Taphofacies theory. Second, how to establish taphofacies which can be used in turbidites and storm deposits and used in fresh water depositional environments. The fresh water environments are very different with the ocean environments, therefore, the fossil preservation types in the fresh water depositional environments also show different characteristic. Although the theories still have shortage, they provide information important in paleoecological studies and rebuild depositional environments.
1992, 10(1): 47-56.
Abstract:
The Permian depositional environment of Maomaolong Formation in Malonggou is hot point in the research of West Qingling Mountains, this paper deals with it in detail and four physical characteritics were distinguished: 1. Carbonate debris and turbidite, consisting of conglomeratic carbonate rock. The turbidite has an incomplete Bouma sequence with graded bedding and paralled stratification. 2.Clastic debris, turbidite and grain flow sandstone, consisting of conglomerate, gravel sandstone, siltstone and slate. The turbidite has a complete Bonma sequence with gutter cast, graded bedding, small hummocky crossbedding and horizontal stratification. The grain flow sandstone has reverse-graded bedding. S.Contourite, consisting of siltstone and silty slate with horizontal stratification and water-current ripple. The direction of water-current is 97° -107°, being vertical with the direction of turbidite. 4. Normal deep-sea sediments of non-gravity current, consisting of silty slate, and the small horizontal stratification being found occasionally. Seven chemical compositions of mudstone from normal deep-sea, sediments have been determined, they were analysed to be similar to the modern deep-sea sediments. TiO2 / Al2O3 values of Malonggou section decrease with the decrease of depth showing the depositional environment was departing from the continental region. A trace fossil association of Neonereites- Protopaleodictyon. was established which has the ecdogical characters of slope environment. According to the above-mentioned sedimentary feature, the late Early Permian to Late Permian slope environment of Maomaolong Formation was resumed. The depositional basin continued subsiding with the splitting of Paleo-Qinling trough, and developed to a slope foot-basin environment in late Late Permian. The direction of gutter casts (320 ° -340 ° ) and the distribution of the conglomeratic carbonate rock indicate that the slope was inclined to south at that time, belonging to the Northern Slope of the Paleo-Qinling trough. And the angle of the slope was calculated to be 1 ° or 2 ° to 18 °, and had the tendency of getting smaller in the lower slope.
The Permian depositional environment of Maomaolong Formation in Malonggou is hot point in the research of West Qingling Mountains, this paper deals with it in detail and four physical characteritics were distinguished: 1. Carbonate debris and turbidite, consisting of conglomeratic carbonate rock. The turbidite has an incomplete Bouma sequence with graded bedding and paralled stratification. 2.Clastic debris, turbidite and grain flow sandstone, consisting of conglomerate, gravel sandstone, siltstone and slate. The turbidite has a complete Bonma sequence with gutter cast, graded bedding, small hummocky crossbedding and horizontal stratification. The grain flow sandstone has reverse-graded bedding. S.Contourite, consisting of siltstone and silty slate with horizontal stratification and water-current ripple. The direction of water-current is 97° -107°, being vertical with the direction of turbidite. 4. Normal deep-sea sediments of non-gravity current, consisting of silty slate, and the small horizontal stratification being found occasionally. Seven chemical compositions of mudstone from normal deep-sea, sediments have been determined, they were analysed to be similar to the modern deep-sea sediments. TiO2 / Al2O3 values of Malonggou section decrease with the decrease of depth showing the depositional environment was departing from the continental region. A trace fossil association of Neonereites- Protopaleodictyon. was established which has the ecdogical characters of slope environment. According to the above-mentioned sedimentary feature, the late Early Permian to Late Permian slope environment of Maomaolong Formation was resumed. The depositional basin continued subsiding with the splitting of Paleo-Qinling trough, and developed to a slope foot-basin environment in late Late Permian. The direction of gutter casts (320 ° -340 ° ) and the distribution of the conglomeratic carbonate rock indicate that the slope was inclined to south at that time, belonging to the Northern Slope of the Paleo-Qinling trough. And the angle of the slope was calculated to be 1 ° or 2 ° to 18 °, and had the tendency of getting smaller in the lower slope.
1992, 10(1): 68-75.
Abstract:
This paper centers on the study of the characteristics of the series of fluorene and C6 compound in the condensate and the light oil associated with natural gas, and deals with sedimentary environments and the gas-source rocks. After GC and GC-MS methods were applied for analysis of more than 40 samples from basins in China, these singifie ve data suggest as ffollows: (1) There are obvious differences among the contents of C6 compounds in the condensate and the light oil derived from the different sedimentary en romnents. The series of C6 composition in the light hydrocarbon related to the lacustrine-fluvial fades is characterized by higher contents of n-hexane and i-hexane, related to the saline lake fades by relativety higher of benzene and related to the marine facies by higher contents of cyclohexane and methylcyclopenta Moreover, consequent upon the different coal-forming environments, the composition of the condensate which from the coal-bearing series is of some differences. (2) The series of fluorene compound in aromatic hydrocarbon is composed of fluorene, oxygen-bearing fluorene and sulfur-bearing fluorene (F. OF and SF for short). The abundances of these three parts present obvious difference due to derived from various parent materials and sedimentary environments. The condensate from the freshwater lacustrine environment is of higher fluorene content, associated with salt lake and marine presents abundant in sulfur- bearing fluorene and related to the coal- bearing series and swamp sedimentary environment abundant in oxygen- bearing fluorene. Therefore, it is proposed that the series of fluorene compounds and other sulfur-bearing aromatic hydrocarbons could not only be used as one of the main indicators of gas-source matter and sedimentary envoronment but also used to identify genetic types of natural gases.
This paper centers on the study of the characteristics of the series of fluorene and C6 compound in the condensate and the light oil associated with natural gas, and deals with sedimentary environments and the gas-source rocks. After GC and GC-MS methods were applied for analysis of more than 40 samples from basins in China, these singifie ve data suggest as ffollows: (1) There are obvious differences among the contents of C6 compounds in the condensate and the light oil derived from the different sedimentary en romnents. The series of C6 composition in the light hydrocarbon related to the lacustrine-fluvial fades is characterized by higher contents of n-hexane and i-hexane, related to the saline lake fades by relativety higher of benzene and related to the marine facies by higher contents of cyclohexane and methylcyclopenta Moreover, consequent upon the different coal-forming environments, the composition of the condensate which from the coal-bearing series is of some differences. (2) The series of fluorene compound in aromatic hydrocarbon is composed of fluorene, oxygen-bearing fluorene and sulfur-bearing fluorene (F. OF and SF for short). The abundances of these three parts present obvious difference due to derived from various parent materials and sedimentary environments. The condensate from the freshwater lacustrine environment is of higher fluorene content, associated with salt lake and marine presents abundant in sulfur- bearing fluorene and related to the coal- bearing series and swamp sedimentary environment abundant in oxygen- bearing fluorene. Therefore, it is proposed that the series of fluorene compounds and other sulfur-bearing aromatic hydrocarbons could not only be used as one of the main indicators of gas-source matter and sedimentary envoronment but also used to identify genetic types of natural gases.
1992, 10(1): 83-92.
Abstract:
The K and Ar contents and apparent ages of 41 core samples of different depth, time and lithology from oil-gas bearing basins of Bohaiwan, Sichuan and Ordos have been analysed and determined, and the clay minerals of 26 samples from the basins have also been analysed.The distributive characteristics of K and Ar contents in the different districts and time as well as the relationship between K-contents and illite contents of clay minerals in mudrocks have been studied.The distributions of K, Ar contents for mudrocks and carbonate rocks have contrastively been studied.The relationship between of Ar isotopic in sedimentary rocks and natural gases has been studied, too.The results show that: ①The apparent ages is higher than geological ages in younger rocks, but lower in older rocks. ② As contrasted to mudrock, the K and Ar contents are lower in the carbonate rock in the same period. ③The Ar(air)of sedimentary rocks mainly comes from the atmosphere argon which dissolved in sedimentary water and adsorped on fragments. There is a trend of decrease of Ar(air)with the development of diagenesis and the lapse of time. ④ As affected by the evolution of crust, diagenises and tectonics, the K-content contribution is cyclically chracterized, increase from Z to O, and decrease from O to P, than increase from P to J, and reduce since then.The whole evolution above is meiinly divided into two cycles which indicate the active and stable evolution of crust respectively. ⑤Plenty of illite widespreads m mudrocks and there is a good relation between the K -content of mudrocks and illte content of clay mineials. which shows that the K element in mudrock occupied laltices of illite The d art bution of 40 Ar is controlled by geological period lithology, and particularly depends upon the loss dearee of Ar diffusion from rocks and The remanent degree of Ar in detrilal minerals 40Ar in carbonate rock la ecly diffused. By comparison with theoretical value, losted 40 Ar m mudrocks is about 70-90% in pre-Pz. md about 40% in some of Pz 40Ar remained in sediments is about 80 -90% in Kz and about 40 60% in M/ and less than 50% in Pz The lower concentration of 40Ar in pre-Pz resulted from the long pe iod diffusion, but that in Pz-Mz is due to the Ar migration from source rock with natural gas. The h ther 40Ar content in Kz mainly remained in detrital mineral According to the geochemieal and geological data, the following conclusions can be drawn (1) A m sedimentary rocks have three origins the radiogenic Ar trapped in sedimertary detritai minerals, atmos-phere Ar dissolved m sedimertary water then included and adsorpted in the rock and radiogenic Ar m autogeruc K-bearing minerals, (2) Owing to widely existing illites included K-element in the mudroess, the source rocks could contribute 40Ar to natural gases. ( 3) Argon m natural gas enginated radiogemc and atmospheric argon in strata. (4) Argon migrated io gas reverviors by two stepps diffusion or crystal body changed and broken takes the 40Ar out of the crystal skeleton. Desorption atlmosphere argon from rocks surface.Second, both 40Ar and Ar (air) of first migritom graduilly ports by surmounted static water pressure and block condition with water and other getses dioxide, hydrocarbony, nitrogen and others), The velocity of the latter migrtion taster than he former, therefore the contenl of argon is natural gas is in close relationship with The argon of the first m That is the reason why Ihe argon isotopic composition of natural gas reflects the 40Ar chronolsical cumulation effect in the gas source rocks
The K and Ar contents and apparent ages of 41 core samples of different depth, time and lithology from oil-gas bearing basins of Bohaiwan, Sichuan and Ordos have been analysed and determined, and the clay minerals of 26 samples from the basins have also been analysed.The distributive characteristics of K and Ar contents in the different districts and time as well as the relationship between K-contents and illite contents of clay minerals in mudrocks have been studied.The distributions of K, Ar contents for mudrocks and carbonate rocks have contrastively been studied.The relationship between of Ar isotopic in sedimentary rocks and natural gases has been studied, too.The results show that: ①The apparent ages is higher than geological ages in younger rocks, but lower in older rocks. ② As contrasted to mudrock, the K and Ar contents are lower in the carbonate rock in the same period. ③The Ar(air)of sedimentary rocks mainly comes from the atmosphere argon which dissolved in sedimentary water and adsorped on fragments. There is a trend of decrease of Ar(air)with the development of diagenesis and the lapse of time. ④ As affected by the evolution of crust, diagenises and tectonics, the K-content contribution is cyclically chracterized, increase from Z to O, and decrease from O to P, than increase from P to J, and reduce since then.The whole evolution above is meiinly divided into two cycles which indicate the active and stable evolution of crust respectively. ⑤Plenty of illite widespreads m mudrocks and there is a good relation between the K -content of mudrocks and illte content of clay mineials. which shows that the K element in mudrock occupied laltices of illite The d art bution of 40 Ar is controlled by geological period lithology, and particularly depends upon the loss dearee of Ar diffusion from rocks and The remanent degree of Ar in detrilal minerals 40Ar in carbonate rock la ecly diffused. By comparison with theoretical value, losted 40 Ar m mudrocks is about 70-90% in pre-Pz. md about 40% in some of Pz 40Ar remained in sediments is about 80 -90% in Kz and about 40 60% in M/ and less than 50% in Pz The lower concentration of 40Ar in pre-Pz resulted from the long pe iod diffusion, but that in Pz-Mz is due to the Ar migration from source rock with natural gas. The h ther 40Ar content in Kz mainly remained in detrital mineral According to the geochemieal and geological data, the following conclusions can be drawn (1) A m sedimentary rocks have three origins the radiogenic Ar trapped in sedimertary detritai minerals, atmos-phere Ar dissolved m sedimertary water then included and adsorpted in the rock and radiogenic Ar m autogeruc K-bearing minerals, (2) Owing to widely existing illites included K-element in the mudroess, the source rocks could contribute 40Ar to natural gases. ( 3) Argon m natural gas enginated radiogemc and atmospheric argon in strata. (4) Argon migrated io gas reverviors by two stepps diffusion or crystal body changed and broken takes the 40Ar out of the crystal skeleton. Desorption atlmosphere argon from rocks surface.Second, both 40Ar and Ar (air) of first migritom graduilly ports by surmounted static water pressure and block condition with water and other getses dioxide, hydrocarbony, nitrogen and others), The velocity of the latter migrtion taster than he former, therefore the contenl of argon is natural gas is in close relationship with The argon of the first m That is the reason why Ihe argon isotopic composition of natural gas reflects the 40Ar chronolsical cumulation effect in the gas source rocks
1992, 10(1): 101-107.
Abstract:
This paper introduceds a simulated test of phosphoric accumulation by algal culture in the laboratory. The results show that there are two ways to accumulate phosphate. The first, algae promote the formation and diposition of phosphate by change of the pH; the balance system of ions; and the oxidation-reduction potential (Eh) in environment during the logarithmic growth phase. The second, cells get phosphorus by cellular absorption and adsorption. These provided a valuable evidence for the theory of biological mineralization. The main principle of environmental change are as follows: CO2+ H2O=H2CO3H++ HCO3-=2H++CO32- When the CO2 in cultural liquid consumed by algal phosynthesis, the balancing equation moves towards the left, that H+ concentration drops and pH rises. Eh is general reflection of varied ions-fluctuation, it is closely related with pH value in two ways: 1) H+ directly participats in oxidation-reduction reaction. 2) H+ changes the balancing system of original ions by dissociation of reducing agent and oxidizing agent, influence the value of Eh finally. The difference of algal phosphoric accumulation can be seen from Table 4 and Table 5. The accumulation phosphates of algal cells in No. 4 are up to 9.1% of its dry weight. These data show that phosphoric weight of algal bodies are related to PO43- concentration in its habitat and grown days during logarithmic growth stage.
This paper introduceds a simulated test of phosphoric accumulation by algal culture in the laboratory. The results show that there are two ways to accumulate phosphate. The first, algae promote the formation and diposition of phosphate by change of the pH; the balance system of ions; and the oxidation-reduction potential (Eh) in environment during the logarithmic growth phase. The second, cells get phosphorus by cellular absorption and adsorption. These provided a valuable evidence for the theory of biological mineralization. The main principle of environmental change are as follows: CO2+ H2O=H2CO3H++ HCO3-=2H++CO32- When the CO2 in cultural liquid consumed by algal phosynthesis, the balancing equation moves towards the left, that H+ concentration drops and pH rises. Eh is general reflection of varied ions-fluctuation, it is closely related with pH value in two ways: 1) H+ directly participats in oxidation-reduction reaction. 2) H+ changes the balancing system of original ions by dissociation of reducing agent and oxidizing agent, influence the value of Eh finally. The difference of algal phosphoric accumulation can be seen from Table 4 and Table 5. The accumulation phosphates of algal cells in No. 4 are up to 9.1% of its dry weight. These data show that phosphoric weight of algal bodies are related to PO43- concentration in its habitat and grown days during logarithmic growth stage.
1992, 10(1): 118-125.
Abstract:
The new situ-adsorption and measurament system consists of dynamic adsorbed simulation and Fourier Transform Infrarad (FT1R) spectrometer, the situ-adsorption study is particularly important, because it can observes directly adsorbing behaviour from the porous media with montmorillonite bonded on the glass rnicroballs surface. The montmorillonites become various micro- structures of " cloud- sheel", "scalelike", and "assemble-hump" on the surface of glass rnicroballs. The property of the porous media just may be similar to clayrich sandstones. For observation by FTIR spectrometer, the optic element inserting into porous media is a ZnSe crystal of high refractive index and inertness, into which modulation wave beam from FTIR spectrometer is focus-sed at such and angle that it enters the crystal and is internally reflected within it so that the IR beam is trapped. After many reflections the IR beam emerges from the opposite end of the crystal and passes to the detector. At each reflection within the crystal an evanescent wave is produced that penetrates into the porous media in contact with the crystal. If this porous media with montmorillonite and organic solutes absorb infarad, energy will be lost from the crystal (it is attenuated at certain frequency) and corresponding FT-IR spectra can be obtained. Our experiment results of dynamic adsorption confirmed that a realtive organic solutes are singificantly adsobed into montmorillonites and there are both physical and chemical adsorptions on the porous media, simultanneosly.On the basis of situ-adsorbed FTIR spectra data of petroleum sulfoacid group (PSG) into montmorillonite, the high frequency shift 12-39 cm-1 of the OH deforming band of montmorillonite on hydrogen bond formation is accompanied by an increase in intensity and a broadening and splitting double peaks of the band. However bridge bond formtion is low frequency shift 15 cm-1 of CH3 stretching band of PSG. It is indicate that monovalent organic anion, PSG, most enter between both lattice-layers of montmorillonite, because hydrophilic group and ydrophobic group of PSG to conned become bridge bond and hydrogen bond with lattice water and silicon-oxygen group in montmorillorite, respectively. Demonstration a new interest in our experiments that by adequately choosing the PSG concentration (900-1600 ppm, the adsorption density can be substantially increase convert PSG into micelle. Therefore, as mentioned above experimental results, distinct adsorbed behaviour is situ-observed for PSG have a high degree of centralism between both lattice-layers of mintmorillonite to form layer-micelle. We would like to comment that the lattice-layers of montmorillonite is a cryptand of structure of three-dimensional space, that is a "micro-environment" with catalytic property. The montmorillonites of edhydration will be accompained with transport of organic substance from lattice-layers of montmorillonites when montmorillonites change into illites. Therefore, it has geological significance of very mportance, because the results indicated causal relation which a great deal organic substances storage and transport from montmorillonites in the stratum.
The new situ-adsorption and measurament system consists of dynamic adsorbed simulation and Fourier Transform Infrarad (FT1R) spectrometer, the situ-adsorption study is particularly important, because it can observes directly adsorbing behaviour from the porous media with montmorillonite bonded on the glass rnicroballs surface. The montmorillonites become various micro- structures of " cloud- sheel", "scalelike", and "assemble-hump" on the surface of glass rnicroballs. The property of the porous media just may be similar to clayrich sandstones. For observation by FTIR spectrometer, the optic element inserting into porous media is a ZnSe crystal of high refractive index and inertness, into which modulation wave beam from FTIR spectrometer is focus-sed at such and angle that it enters the crystal and is internally reflected within it so that the IR beam is trapped. After many reflections the IR beam emerges from the opposite end of the crystal and passes to the detector. At each reflection within the crystal an evanescent wave is produced that penetrates into the porous media in contact with the crystal. If this porous media with montmorillonite and organic solutes absorb infarad, energy will be lost from the crystal (it is attenuated at certain frequency) and corresponding FT-IR spectra can be obtained. Our experiment results of dynamic adsorption confirmed that a realtive organic solutes are singificantly adsobed into montmorillonites and there are both physical and chemical adsorptions on the porous media, simultanneosly.On the basis of situ-adsorbed FTIR spectra data of petroleum sulfoacid group (PSG) into montmorillonite, the high frequency shift 12-39 cm-1 of the OH deforming band of montmorillonite on hydrogen bond formation is accompanied by an increase in intensity and a broadening and splitting double peaks of the band. However bridge bond formtion is low frequency shift 15 cm-1 of CH3 stretching band of PSG. It is indicate that monovalent organic anion, PSG, most enter between both lattice-layers of montmorillonite, because hydrophilic group and ydrophobic group of PSG to conned become bridge bond and hydrogen bond with lattice water and silicon-oxygen group in montmorillorite, respectively. Demonstration a new interest in our experiments that by adequately choosing the PSG concentration (900-1600 ppm, the adsorption density can be substantially increase convert PSG into micelle. Therefore, as mentioned above experimental results, distinct adsorbed behaviour is situ-observed for PSG have a high degree of centralism between both lattice-layers of mintmorillonite to form layer-micelle. We would like to comment that the lattice-layers of montmorillonite is a cryptand of structure of three-dimensional space, that is a "micro-environment" with catalytic property. The montmorillonites of edhydration will be accompained with transport of organic substance from lattice-layers of montmorillonites when montmorillonites change into illites. Therefore, it has geological significance of very mportance, because the results indicated causal relation which a great deal organic substances storage and transport from montmorillonites in the stratum.
Diagenetic Histories of Reef Corals in the Late Quaternary Huon Raised Coral Reefs, Papua New Guinea
1992, 10(1): 133-145.
Abstract:
A series of late Quaternary raised coral reef terraces, mainly consisting of Indo-Pacific shallow water reef-corals and reef limestones, occur along the northeast coast of the Huon Peninsula, Papua New Guinea.The diagenetic alterations of the reef-corals and internal sediments reflect the diagenetic history of the Huon reefs are described for the first time through field investigations, petrologic, and geochemical analyses ot samples taken along three transects representing different environmental conditions.The results indicate that rapid tectonic uplift at the Huon Peninsula not only has a great effect on the formation and development of the coral reef terraces, but also plays an important part in the diagenetic history. Reef-corals in the Huon reefs have undergone marine phreatic, marine vadose, meteoric phreatie,and meteoric vadose diagenetic alterations Owing to the rapid tectonic uplift, the most significant diagenesis occurs in marine phreatic and meteoric vadose environments. The dominant diagenetic alterations experienced by the reef-corals are boring, sedimentation of internal sediments, coarsening of fibrous aragonite coral skeletons (formation of secondary aragonite), dissolution and neomorphic transformation of corals. and cementation of varied mineralogical and crystal fabric cements.Borings and deposition of internal sediments occur mainly in the marine environment and greatly modify the coral framework, while dissolution and neomorphic transformation of coral skeletons are predominant in meteoric diagenetic environments.The coral reef terraces present extensively karst morphology. Most samples examined show that dissolution of coral skeleton begins at the centres of trabeculae, and that any secondary pores produced are either filled by sparry calcite cement or remain empty. Selective dissolution of different componants of corals is obvious. It is often shown that with the coral skeleton dissolved, the rim of aragonite fibrous cement, syntaxially growing on them is preserved, This suggests that coral aragonite fibres are relatively unstable compared to inorganically precipitated aragonite. Neomorphic transformation of coral skeletons in the Huon reefs to calcite is the most widespreaded diagenetic alteration. Almost all coral skeletons in samples which are now calcite have only experienced neomorphic alteration during their transformation. Very few corals have undergone transformation to calcite as a result of total leaching of the coral skeleton and later precipitation of calcite cement. Cementation occurs in both marine and meteoric environments. The cements which are formed in the marine environment are aragonite and Mg-calcite in mineralogy and tend to be fibrous and rhombic in crystal structures, while those formed in the meteoric environment are all calcite in mineralogy and are commonly blocky. Coarsening of coral aragonite fibers only changes their fabrics, not the mineralogical and chemical composition. The process causing the coarsening of the coral aragonite fibres is unknown. Geochemical work shows that diagenesis operates in a chemically open system.Diagenetic products from the marine environment are characterised by relatively higher strontium and sodium contents, and those from meteoric environments by lower contents of strontium and sodium, and variable magnesium.
A series of late Quaternary raised coral reef terraces, mainly consisting of Indo-Pacific shallow water reef-corals and reef limestones, occur along the northeast coast of the Huon Peninsula, Papua New Guinea.The diagenetic alterations of the reef-corals and internal sediments reflect the diagenetic history of the Huon reefs are described for the first time through field investigations, petrologic, and geochemical analyses ot samples taken along three transects representing different environmental conditions.The results indicate that rapid tectonic uplift at the Huon Peninsula not only has a great effect on the formation and development of the coral reef terraces, but also plays an important part in the diagenetic history. Reef-corals in the Huon reefs have undergone marine phreatic, marine vadose, meteoric phreatie,and meteoric vadose diagenetic alterations Owing to the rapid tectonic uplift, the most significant diagenesis occurs in marine phreatic and meteoric vadose environments. The dominant diagenetic alterations experienced by the reef-corals are boring, sedimentation of internal sediments, coarsening of fibrous aragonite coral skeletons (formation of secondary aragonite), dissolution and neomorphic transformation of corals. and cementation of varied mineralogical and crystal fabric cements.Borings and deposition of internal sediments occur mainly in the marine environment and greatly modify the coral framework, while dissolution and neomorphic transformation of coral skeletons are predominant in meteoric diagenetic environments.The coral reef terraces present extensively karst morphology. Most samples examined show that dissolution of coral skeleton begins at the centres of trabeculae, and that any secondary pores produced are either filled by sparry calcite cement or remain empty. Selective dissolution of different componants of corals is obvious. It is often shown that with the coral skeleton dissolved, the rim of aragonite fibrous cement, syntaxially growing on them is preserved, This suggests that coral aragonite fibres are relatively unstable compared to inorganically precipitated aragonite. Neomorphic transformation of coral skeletons in the Huon reefs to calcite is the most widespreaded diagenetic alteration. Almost all coral skeletons in samples which are now calcite have only experienced neomorphic alteration during their transformation. Very few corals have undergone transformation to calcite as a result of total leaching of the coral skeleton and later precipitation of calcite cement. Cementation occurs in both marine and meteoric environments. The cements which are formed in the marine environment are aragonite and Mg-calcite in mineralogy and tend to be fibrous and rhombic in crystal structures, while those formed in the meteoric environment are all calcite in mineralogy and are commonly blocky. Coarsening of coral aragonite fibers only changes their fabrics, not the mineralogical and chemical composition. The process causing the coarsening of the coral aragonite fibres is unknown. Geochemical work shows that diagenesis operates in a chemically open system.Diagenetic products from the marine environment are characterised by relatively higher strontium and sodium contents, and those from meteoric environments by lower contents of strontium and sodium, and variable magnesium.
1992, 10(1): 11-18.
Abstract:
Olistostrome of gravity flow are found in the Middle and Upper Ordovician in the western and southern margin of Ordos Basin, Some of great boulders, and allochthons as irregular long-cylinder or stratoid structure with ten to one hundres meters long are found in parts of the strata, as the allochthons are dishar-monious obviously with the host rock, it suggests that the orgins are different. The pefrdogic characters, stratigraphic horizon, the assembledge of rock and forming of olistostrome ard discussed. It proposed by the author that the olistostrome is formed on the steep gradient zones of passive continental margin of rifts, where great boulders and allochthons are produced by collapse and carried by gravity flows.
Olistostrome of gravity flow are found in the Middle and Upper Ordovician in the western and southern margin of Ordos Basin, Some of great boulders, and allochthons as irregular long-cylinder or stratoid structure with ten to one hundres meters long are found in parts of the strata, as the allochthons are dishar-monious obviously with the host rock, it suggests that the orgins are different. The pefrdogic characters, stratigraphic horizon, the assembledge of rock and forming of olistostrome ard discussed. It proposed by the author that the olistostrome is formed on the steep gradient zones of passive continental margin of rifts, where great boulders and allochthons are produced by collapse and carried by gravity flows.
1992, 10(1): 27-35.
Abstract:
North China represents a vast area bounded on the north by Yinshan Oldland, on the south by Qingl-ing-Dabie Mountain, on the east by Tanlu fault and on the west by Luliang Moutain. This paper deals with 33 outcrop sections and drill sections in North China in detail. Depending on lithology, grain size, sedimentary structures, colors and thickness of sandbeds, the Permian (Shanxi Formation, Upper and Lower Shihezi Formations) clastic rocks were defined as 13 microfacies- lithofacies. Their mutual assemlages in vertical make up different types of lithofacies associations or sequences, each corresponding to a certain sedimentary process and environment. Therefore, ten types of lithlfaeies associations, with eight being fluvial environments were recognized and modelled. The Permian and Carboniferous in study area are the contineousi deposit. Paleogeographically, the Permian, though still bearing some Carboniferous features, assumed a quite different look, with south-ward retreating sea and more continental facies. The main depositional systems active in Permian are as follows: 1) alluvial plain system, 2) deltaic distributary plain system, and 3) tidal flat-sea inlet system. The provenance are dominated by Yinshan Oldland and Qingling-Dabie Mountain also has a little supply of elastics. Consequently, the Permain in North China is a regression cycle with fluvial deposits predominating The grain sizes become finner and finner from north with the increasing caol beds. The Permain paleoclimate from early to late shows a gradual change from warm moisture to aridness. The coal-bearing gas of commercial values and some oil have been found in Permian of North China. The first to sixth types of lithofacies associations are the favourable foiTnations for development of reservoir rocks. In view of this, the northern parts are more favourable zones for oil and gas exploration than the southern parts in North China. The paper uses lithofacies and its associations in Permain of North China to deal with the featuer, style and distribution in space and time of the various types of fluvial deposits. The classification of fluvial shapes does not probably reflect the whole process of fluvial deposits. The study in lithofacies associations types and the sequences textures is a better method to reflect fluvial enviornments for its geomophic feature and hydroclynamic conditions changes which formed a series of liffe ect fmval enviornments.
North China represents a vast area bounded on the north by Yinshan Oldland, on the south by Qingl-ing-Dabie Mountain, on the east by Tanlu fault and on the west by Luliang Moutain. This paper deals with 33 outcrop sections and drill sections in North China in detail. Depending on lithology, grain size, sedimentary structures, colors and thickness of sandbeds, the Permian (Shanxi Formation, Upper and Lower Shihezi Formations) clastic rocks were defined as 13 microfacies- lithofacies. Their mutual assemlages in vertical make up different types of lithofacies associations or sequences, each corresponding to a certain sedimentary process and environment. Therefore, ten types of lithlfaeies associations, with eight being fluvial environments were recognized and modelled. The Permian and Carboniferous in study area are the contineousi deposit. Paleogeographically, the Permian, though still bearing some Carboniferous features, assumed a quite different look, with south-ward retreating sea and more continental facies. The main depositional systems active in Permian are as follows: 1) alluvial plain system, 2) deltaic distributary plain system, and 3) tidal flat-sea inlet system. The provenance are dominated by Yinshan Oldland and Qingling-Dabie Mountain also has a little supply of elastics. Consequently, the Permain in North China is a regression cycle with fluvial deposits predominating The grain sizes become finner and finner from north with the increasing caol beds. The Permain paleoclimate from early to late shows a gradual change from warm moisture to aridness. The coal-bearing gas of commercial values and some oil have been found in Permian of North China. The first to sixth types of lithofacies associations are the favourable foiTnations for development of reservoir rocks. In view of this, the northern parts are more favourable zones for oil and gas exploration than the southern parts in North China. The paper uses lithofacies and its associations in Permain of North China to deal with the featuer, style and distribution in space and time of the various types of fluvial deposits. The classification of fluvial shapes does not probably reflect the whole process of fluvial deposits. The study in lithofacies associations types and the sequences textures is a better method to reflect fluvial enviornments for its geomophic feature and hydroclynamic conditions changes which formed a series of liffe ect fmval enviornments.
1992, 10(1): 57-67.
Abstract:
Ruyang Group, consisting of the Yunmengshan, Baicaoping, ;and Beidajian formations in an sacend-ing order. is the first sedimentary sequence overlying the Precambrian volcanic rocks in western Henan>which is geologically situated on the southern margin of North China Platform. Detailed facies and fades as-socia.tion analyses show that Ruyang Group was formed in tide- and storm-influenced coastal and innershelf environments. The group can be divided into nine main facies coarse-grained sandstone/conglomerate(F1)，trough crossbedded sandstone(F2)，compound crossbedded snadstone(F3)，giant planarcross;bedded sandstone(F4)，hummocky cross- stratified sandstone(F5)，flat bedded sandstone(F6)，low-angle crossbedded sandstone ( F7)，interbedded sandstone/mudstone (F8) and channeldeposits facies (F9).
Ruyang Group, consisting of the Yunmengshan, Baicaoping, ;and Beidajian formations in an sacend-ing order. is the first sedimentary sequence overlying the Precambrian volcanic rocks in western Henan>which is geologically situated on the southern margin of North China Platform. Detailed facies and fades as-socia.tion analyses show that Ruyang Group was formed in tide- and storm-influenced coastal and innershelf environments. The group can be divided into nine main facies coarse-grained sandstone/conglomerate(F1)，trough crossbedded sandstone(F2)，compound crossbedded snadstone(F3)，giant planarcross;bedded sandstone(F4)，hummocky cross- stratified sandstone(F5)，flat bedded sandstone(F6)，low-angle crossbedded sandstone ( F7)，interbedded sandstone/mudstone (F8) and channeldeposits facies (F9).
1992, 10(1): 76-82.
Abstract:
As the organic geochemical characteristics of marine carbonate rocks from Sinian to Triassic (Southernwest China) was studied, it was discovered that a vast amount of the extractable organic matter ( EOM) was present in carbonate cryptomerous minerals, which was wrapped up in them during early diagenesis. The organic matter was obtained by stepwise extraction in conjunction with stepwise dissolution of the carbonate and subsequently silicate minerals. The amount of the bound bitumen comes up to 176.96~ 1438.68 ppm with the average of 721.95 ppm in three limestone samples at lower maturity (R°= 0. -1.0%, over 22 percent of the total amount of the EOM. The bitumen fractions associated with minerals have the low mature features which are indicated by high content of colloid and asphaltene, obvious carbon number predominance of n-alkanes, the high concentration of unstable isomers of steranes (aa and R types), a large number of multicyclic and isomeric alkanes (e.g. C21-C40 isoprenoids, C19-C39 lng chain alkyl tricyclic terpanes, hopanes, benzohopanes, aromatic steranes etc.). When the evolution of organic matter reaches early stage of over-maturity (Rc (calculated vitrinite reflectance≈2.0%, Tmax ≈485℃, the bound bitumen fractions began to release from carbonate minerals and generate liquid hydrocarbons namely "high temperature oil". The generation tends to its end as Rc exceeds 3.0%. The processes have been verified by a thermal experiment in laboratory. Therefore, contributions to the formation of oil and in carbonate are made not only by kerogen but also by associated organic matter. Owing to the main components of carbonate organic matter are protein. carbohydrate and lipid, and the kerogen content in carbonate rocks is lower (about 50 percent of the total amount of organic matter) the mudstone, it appears that the soluble organic matter (free and bound) in carbonate produces directly hydrocarbons is more important.
As the organic geochemical characteristics of marine carbonate rocks from Sinian to Triassic (Southernwest China) was studied, it was discovered that a vast amount of the extractable organic matter ( EOM) was present in carbonate cryptomerous minerals, which was wrapped up in them during early diagenesis. The organic matter was obtained by stepwise extraction in conjunction with stepwise dissolution of the carbonate and subsequently silicate minerals. The amount of the bound bitumen comes up to 176.96~ 1438.68 ppm with the average of 721.95 ppm in three limestone samples at lower maturity (R°= 0. -1.0%, over 22 percent of the total amount of the EOM. The bitumen fractions associated with minerals have the low mature features which are indicated by high content of colloid and asphaltene, obvious carbon number predominance of n-alkanes, the high concentration of unstable isomers of steranes (aa and R types), a large number of multicyclic and isomeric alkanes (e.g. C21-C40 isoprenoids, C19-C39 lng chain alkyl tricyclic terpanes, hopanes, benzohopanes, aromatic steranes etc.). When the evolution of organic matter reaches early stage of over-maturity (Rc (calculated vitrinite reflectance≈2.0%, Tmax ≈485℃, the bound bitumen fractions began to release from carbonate minerals and generate liquid hydrocarbons namely "high temperature oil". The generation tends to its end as Rc exceeds 3.0%. The processes have been verified by a thermal experiment in laboratory. Therefore, contributions to the formation of oil and in carbonate are made not only by kerogen but also by associated organic matter. Owing to the main components of carbonate organic matter are protein. carbohydrate and lipid, and the kerogen content in carbonate rocks is lower (about 50 percent of the total amount of organic matter) the mudstone, it appears that the soluble organic matter (free and bound) in carbonate produces directly hydrocarbons is more important.
1992, 10(1): 93-100.
Abstract:
The extraordinary outburst of CO2 gas, coal and rocks happened on May 24, 1978 in aojie oalfield. The isotope compositions of the outburst gas and the carbonates relating to CO2 gas. The results arc as follows: The δ13C values of the CO2 gas are -0.55-4.81‰; and that of ealcitc veins are -15.88-+5.94‰ which are tending to be heavier with the. decrease of depth. The δ13O alues PDB. the same below) of the calcite distributed from-8.07 to-20.4‰; The values of δ13C and δ13 O of parry iron are-1.96-+2.66‰ and -8.55-11.97‰ respectively; The average δ13C value of HCO3 in the barnt rock water is 2.325‰, and based on it, the calculated δ13C value of the primary CO2 dissolved a the wanter is about -6‰, but that of free CO2 released the solution is about -7‰; The δ13C can onate precipi-laied fron, the burnt rock water are 3.89-4.63‰, heavier than those of the HCO3 dissolved in water. The above results show that there are isotope fractionation of carbon in the processes of the disselving and degassing of CO2 gas and the precipitating of the carbonate. As the variation of the δ13C values of the CO, in the coal measures of the field is broad (The lightest is -43.44‰, it is difficult to simply of CO gas with the carberrates in their isolopic compositions. The He/4 He value of the gas in the outburst spot is (3.8±0.5)×108, showing that the outburst gas is a sypteal crust source gas. So it is necessary to strengthen the studying in geology and geochemistry er the eoalfitld ill itself for searching into the concrete source of the outburst gas.
The extraordinary outburst of CO2 gas, coal and rocks happened on May 24, 1978 in aojie oalfield. The isotope compositions of the outburst gas and the carbonates relating to CO2 gas. The results arc as follows: The δ13C values of the CO2 gas are -0.55-4.81‰; and that of ealcitc veins are -15.88-+5.94‰ which are tending to be heavier with the. decrease of depth. The δ13O alues PDB. the same below) of the calcite distributed from-8.07 to-20.4‰; The values of δ13C and δ13 O of parry iron are-1.96-+2.66‰ and -8.55-11.97‰ respectively; The average δ13C value of HCO3 in the barnt rock water is 2.325‰, and based on it, the calculated δ13C value of the primary CO2 dissolved a the wanter is about -6‰, but that of free CO2 released the solution is about -7‰; The δ13C can onate precipi-laied fron, the burnt rock water are 3.89-4.63‰, heavier than those of the HCO3 dissolved in water. The above results show that there are isotope fractionation of carbon in the processes of the disselving and degassing of CO2 gas and the precipitating of the carbonate. As the variation of the δ13C values of the CO, in the coal measures of the field is broad (The lightest is -43.44‰, it is difficult to simply of CO gas with the carberrates in their isolopic compositions. The He/4 He value of the gas in the outburst spot is (3.8±0.5)×108, showing that the outburst gas is a sypteal crust source gas. So it is necessary to strengthen the studying in geology and geochemistry er the eoalfitld ill itself for searching into the concrete source of the outburst gas.
1992, 10(1): 108-117.
Abstract:
With the method of neutron activation analysis(NAA), the concentrations of trace transition elements: Sc, V, Cr, Mn, Fe, Co, Ni, and Zn in crude oils and organic materials extracted from source rocks from the Jianghan oil field have been determined. The concentrations of these elements in the separated fractions: asphaltene, non-hydrocarbon and aromatic hydrocarbon have been also studied. The comparison of the concentrations of trace transition elements in different fractions and the correlations among all the elements have been studied and discussed in detail. To research the relationship among the sources of crude oils and source rocks, the biomarkers have been determined from several samples of crude oils and source rocks, and the results show that these samples are of the same source. Meanwhile, the concentrations of trace transition elements in the same samples have also been determined. The logarithmic distributions normalized to the ratios of concentrations and the concentrations normalized to the related values of elemental concentrations in the North American Shale Composites have been studied. The results show that the patterns of the logarithmic distributions among the crude oils or source rocks, which are of same source, are very similar, and so are among the correlated fractions of these samples. Therefore, it is proposed that these patterns are useful in the correlation among crude oils and source rocks, and it may be better to use these patterns in the correlation than to directly use the concentrations or rations of some trace elements.
With the method of neutron activation analysis(NAA), the concentrations of trace transition elements: Sc, V, Cr, Mn, Fe, Co, Ni, and Zn in crude oils and organic materials extracted from source rocks from the Jianghan oil field have been determined. The concentrations of these elements in the separated fractions: asphaltene, non-hydrocarbon and aromatic hydrocarbon have been also studied. The comparison of the concentrations of trace transition elements in different fractions and the correlations among all the elements have been studied and discussed in detail. To research the relationship among the sources of crude oils and source rocks, the biomarkers have been determined from several samples of crude oils and source rocks, and the results show that these samples are of the same source. Meanwhile, the concentrations of trace transition elements in the same samples have also been determined. The logarithmic distributions normalized to the ratios of concentrations and the concentrations normalized to the related values of elemental concentrations in the North American Shale Composites have been studied. The results show that the patterns of the logarithmic distributions among the crude oils or source rocks, which are of same source, are very similar, and so are among the correlated fractions of these samples. Therefore, it is proposed that these patterns are useful in the correlation among crude oils and source rocks, and it may be better to use these patterns in the correlation than to directly use the concentrations or rations of some trace elements.
1992, 10(1): 126-132.
Abstract:
The identification and quantitative determination of clay minerals is an important work for evaluating the ore-deposit of clay and studying the distribution of estuary and coastle sediments and the reservoir of iol field The combination of SEM (Scanning Electron Microscopy) and EDX (Energy dispersive analysis of X-ray) is used to analyse samples, by which, the micro-area compositions of clay minerals and the average compositions of whole-sample can be got.The mineral contents of sample can be calculated by advanced computer program which can be made by this apparatus.The samples used in condition fest of SEM / EDX are the assemblage of refined clay minerals with various proportion and relative error of experiment is less than 5%. In order to check the practicality of this method, the quantitative analysis of the weathering sepiolite from Hunan province and the attapulgite from Jiashan in Anhui province and Jintan in Jiangsu province are made. All results are satisfying. Such, this method can be used to provide evidents for recognizing combinatory character of minerals in mining-area and evaluating ore-deposit of clay.
The identification and quantitative determination of clay minerals is an important work for evaluating the ore-deposit of clay and studying the distribution of estuary and coastle sediments and the reservoir of iol field The combination of SEM (Scanning Electron Microscopy) and EDX (Energy dispersive analysis of X-ray) is used to analyse samples, by which, the micro-area compositions of clay minerals and the average compositions of whole-sample can be got.The mineral contents of sample can be calculated by advanced computer program which can be made by this apparatus.The samples used in condition fest of SEM / EDX are the assemblage of refined clay minerals with various proportion and relative error of experiment is less than 5%. In order to check the practicality of this method, the quantitative analysis of the weathering sepiolite from Hunan province and the attapulgite from Jiashan in Anhui province and Jintan in Jiangsu province are made. All results are satisfying. Such, this method can be used to provide evidents for recognizing combinatory character of minerals in mining-area and evaluating ore-deposit of clay.
