The record of paleo-environment in clayey aquitard pore water is much more effective relative to aquifer groundwater owing to the low permeability of clayey aquitard. Oxygen-18（18O）, deuterium（D）, and chemical pat...The record of paleo-environment in clayey aquitard pore water is much more effective relative to aquifer groundwater owing to the low permeability of clayey aquitard. Oxygen-18（18O）, deuterium（D）, and chemical patterns were determined in pore water samples extracted from two 500 m depth boreholes, G1 and G2, in western Bohai Bay, China. Shallow pore water samples（depth〈102 m） are saline water, with the TDS（total dissolved solids） of 3.69–30.75 g/L, and deeper ones（depth=102–500 m） are fresh water, with the TDS〈1 g/L. Content of major ions（i.e., Cl-, Na＋, K＋, Mg2＋, SO2-4, Ca2＋） is high in marine sediment pore water samples and gradually decrease towards to terrestrial sediment pore water, together with the Cl/Br and Sr/Ba ratios changing significantly in different sedimentary facies along the study profile, indicating that pore water may be paleo-sedimentary water and not replaced by modern water. δ18O profile and positive correlation between δ18O and Cl- of shallow saline pore water indicated diffusion as the main transport mechanism, and distinguished four transgressive layers since Late Quaternary（i.e., Holocene marine unit, two Late Pleistocene marine units and Middle Pleistocene marine unit）, further supporting the finding that pore water retained the feature of paleo-sedimentary water. Climate was identified as the main influence on the isotopic signature of aquitard pore water and four climate periods were determined by δ18O profile.展开更多
The carbon isotopic composition of organic matter （δ^13Corg） was determined in two sediment cores （IIL1 and IIL9） recovered from Inexpressible Island, Ross Sea, Antarctica, and analyzed to identify the sources of...The carbon isotopic composition of organic matter （δ^13Corg） was determined in two sediment cores （IIL1 and IIL9） recovered from Inexpressible Island, Ross Sea, Antarctica, and analyzed to identify the sources of that organic matter. The δ^13Corg values of sediments of IIL9 were found to vary between -14.6‰ and -11.6‰, with a mean of-13.4‰ （n=48）. These values were significantly higher than those of IIL1 sediments which varied between -23.2‰ and -20.4‰, with a mean of-21.8%o （n=55）. The variation in δ^13Corg values in these two sediment cores indicate different sources of organic matter, The relatively high 6~3Corg values in IIL9 are in accordance with a source from algae, while the low δ^13Corg values in IIL1 evince significant influence from penguin guano with algae as the secondary source. Compared with the reference data from other high-latitude lake sediments and plants, the δ^13Corg values in IIL9 were extremely high, a result likely related to intense competition for CO2 assimilation among algal species during the growing season in this relatively shallow pond. These results indicate that sedimentary δ^13Corg is a reliable proxy for paleo-primary productivity in ponds at Inexpressible Island.展开更多
The indices related to sedimentary pyrite are widely used in paleo-environmental studies; however its application principles and flaws have not been presented in detail so far,therefore it is necessary to review the c...The indices related to sedimentary pyrite are widely used in paleo-environmental studies; however its application principles and flaws have not been presented in detail so far,therefore it is necessary to review the controlling factors of them. In this study the authors described the application principles in detail,including pyrite morphology,C/S ratio,DOP,size distribution,sulfur isotope,and further discussed the C-S-Fe system in oil shale in Meihe Formation which indicates oxic or suboxic conditions during oil shale deposition. The concentration of TOC and S in the oil shale in Meihe Formation is more than that in background mudstone,and the pyrite formation is limited by sulfate. Therefore studying the indices related to pyrite proves to be of great importance.展开更多
Combined methods for mineralogical identifications were used to characterise the clay deposits within the Lower Benue Trough of Nigeria to interpret paleo-environmental conditions,the paleoclimatic significance of the...Combined methods for mineralogical identifications were used to characterise the clay deposits within the Lower Benue Trough of Nigeria to interpret paleo-environmental conditions,the paleoclimatic significance of the trough,and effects of weathering on the minerals as factors that favour its deposition/accumulation within the trough which host other important industrial minerals like coal,barite,limestone etc.Bulk-sample random-powder XRD data and data for clay fractions deposited onto zero-background quartz plates were measured.The samples contained kaolinite,vermiculite,and traces of smectite,and the non-clay phases included quartz,microcline,and muscovite.All samples were unaffected after glycolation,confirming the absence of significant smectite.Muscovite was characterized by the nature of its 10Åbasal peak with a width of<0.10°2θ,which was very sharp.DTA/TGA results support the presence of kaolinite,and the characteristic kaolinite O-H,Al-OH,Si-OH and Si-O-Al FTIR bands also confirmed its presence.Vermicular and book-like morphologies were observed under the SEM,typical of kaolinitic clay from in situ alteration.High kaolinite abundance in these sediments is consistent with intense weathering of parent rocks rich in Al under wet/tropical paleo-climatic conditions with fresh and/or brackish water conditions in a continental setting.The variety of observed morphologies suggests that the deposits suffered more of chemical weathering.The clay deposits in Lower Benue Trough are quartz-rich,kaolinitic and derived from the chemical weathering of Al-rich source rocks.展开更多
Using five group dating of the fossil by Uranium series age method shows that the age of Nanjing Homo Erectus is between 280－ 430 ka B. P. Combining with the analysis of fossil mammalian form Stegodon, Sus.Lydekkeri ...Using five group dating of the fossil by Uranium series age method shows that the age of Nanjing Homo Erectus is between 280－ 430 ka B. P. Combining with the analysis of fossil mammalian form Stegodon, Sus.Lydekkeri Zdansly, M.pachyosteus Young, P.grayi Zdansky and E.SanmeniensisTeilhard et Pive teau, which are located in the same stratum, the authors thinks that the Nanjing Homo Erectus may have lived in the late Mid Pleistocene (about 350 ka B.P.). Based upon the spores and pollen in the cave sediments of the area, we can find that most of spores and pollen are subtropical and warm temperature types. For instance, broad leaf trees which are fond of warm climate, including Cunning hamia, Jsuga and Pinus ,as well as Morus, Carpinus and Ptendium. Among the above spores and pollen, only Tsuga,Liquidambar, Betula,Ulmus and Salix are the remainders of Humid hot environment from the Tertiary period. Above evidences illustrate that the living environment of the Nanjing Homo Erectus not only was not cloder but also was not drier than the Peking Man’s. It could be said that dry climate and the ice age of the Mid Pleistocene didn’t undergo this area.As for the manner of the Homo Erectus’s making stone artifact and using fire, because now we have not found the evidence of the stone artifact and the ash, the futher excavation to the talus of the Huludong cave should be needed.展开更多
The Paleozoic Wufeng-Longmaxi shale is one of the main horizons for shale gas exploration in Sichuan Basin. Outcrop, core and thin section observations, X-ray diffraction analysis, trace element geochemistry and other...The Paleozoic Wufeng-Longmaxi shale is one of the main horizons for shale gas exploration in Sichuan Basin. Outcrop, core and thin section observations, X-ray diffraction analysis, trace element geochemistry and other methods have been used to understand the sedimentary characteristics and identify hydrocarbon source rocks in suitable sedimentary paleoenvironments in the Wufeng-Longmaxi shale in northern Guizhou Province. The thickness of the Wufeng-Longmaxi Formation ranges from 20 to 200 m and it was mainly deposited on a deep-water shelf. The TOC content is high, up to 5.75%. The main non-organic minerals are detrital quartz and clay minerals, with a little plagioclase feldspar, potassium feldspar, calcite, dolomite and pyrite. There is also biogenic microcrystalline quartz. Six lithofacies have been identified： siliceous shale, clay shale, calcareous shale, silty shale, carbonaceous shale, and muddy siltstone. Using biological Ba, V/（V＋Ni）, TOC, V/Cr, B, Sr/Ba and other indicators, we estimate primary productivity, redox conditions and paleosalinity and show that the early stage of Wufeng-Longmaxi deposition occurred under strong anoxic conditions, high paleosalinity and yielded a high TOC content and an excellent potential shale gas source. The anoxic environment was destroyed at the late stages of Wufeng-Longmaxi deposition, the TOC content decreased, so that it is likely to be a high quality source rock. Organic pores acted as the key reservoir space in the shales, and the pores are mainly mesopose, with most pore diameters less than 20 nm. The siliceous shale has high TOC content and brittle mineral（quartz） content making it an important exploration target for shale oil and gas exploration.展开更多
The Yangshao Culture （approx. 6.9-5.5 ka BP） and the Longshan Culture （approx. 4.6-4.0 ka BP） played important roles in Henan＇s Neolithic Period. Due to spatial distribution of the Yangshao cultural sites, they h...The Yangshao Culture （approx. 6.9-5.5 ka BP） and the Longshan Culture （approx. 4.6-4.0 ka BP） played important roles in Henan＇s Neolithic Period. Due to spatial distribution of the Yangshao cultural sites, they had a river-oriented trend in comparison with those in the Longshan Period. Apart from terrain factors, distribution of the sites in both periods is subject to paleo-environmental changes. The Yangshao Culture originated in Holocene Optimum Period, and the Longshan Culture started in climatic fluctuations prior to Neolithic ending. But the latter owned more sites and wider scopes than the former did. Both the Cultures devel- oped fast in rich rainfall and warm periods, and withered for abrupt cooling events in 5.4 ka BP and 4.0 ka BP respectively. Therefore, the sustainability of Henan＇s Neolithic Cultures is not good as expected. Whilst, the ancient farming acted an irreplaceable part in distribution of human sites, and the need for farming space prompted human sites to expand from the western hilly areas towards the eastern plain of Henan. Moreover, the neighboring cultures poured into Henan and complicated the cultural patterns. Besides, characteristics of the sites in the Erlitou Period suggest that some social factors disturbed the spatial pattern at the end of Neolithic age in Henan.展开更多
基金financially supported by the National Natural Sciences Foundation of China (No. 41272258)the National Basic Research Program of China (No. 2010CB428802)
文摘The record of paleo-environment in clayey aquitard pore water is much more effective relative to aquifer groundwater owing to the low permeability of clayey aquitard. Oxygen-18（18O）, deuterium（D）, and chemical patterns were determined in pore water samples extracted from two 500 m depth boreholes, G1 and G2, in western Bohai Bay, China. Shallow pore water samples（depth〈102 m） are saline water, with the TDS（total dissolved solids） of 3.69–30.75 g/L, and deeper ones（depth=102–500 m） are fresh water, with the TDS〈1 g/L. Content of major ions（i.e., Cl-, Na＋, K＋, Mg2＋, SO2-4, Ca2＋） is high in marine sediment pore water samples and gradually decrease towards to terrestrial sediment pore water, together with the Cl/Br and Sr/Ba ratios changing significantly in different sedimentary facies along the study profile, indicating that pore water may be paleo-sedimentary water and not replaced by modern water. δ18O profile and positive correlation between δ18O and Cl- of shallow saline pore water indicated diffusion as the main transport mechanism, and distinguished four transgressive layers since Late Quaternary（i.e., Holocene marine unit, two Late Pleistocene marine units and Middle Pleistocene marine unit）, further supporting the finding that pore water retained the feature of paleo-sedimentary water. Climate was identified as the main influence on the isotopic signature of aquitard pore water and four climate periods were determined by δ18O profile.
基金the Chinese Arctic and Antarctic Administration of the State Oceanic Administration for project supportthe United States Antarctic Program (USAP)+2 种基金Antarctic Support Contract and Italian Mario Zucchelli Station for logistical support. R. Murray and A. Mc Kenzie provided valuable assistance in the fieldsupported by the National Natural Science Foundation of China (Grant nos. 41576183 and 41376124)National Science Foundation (Grant no. ANT 0739575)
文摘The carbon isotopic composition of organic matter （δ^13Corg） was determined in two sediment cores （IIL1 and IIL9） recovered from Inexpressible Island, Ross Sea, Antarctica, and analyzed to identify the sources of that organic matter. The δ^13Corg values of sediments of IIL9 were found to vary between -14.6‰ and -11.6‰, with a mean of-13.4‰ （n=48）. These values were significantly higher than those of IIL1 sediments which varied between -23.2‰ and -20.4‰, with a mean of-21.8%o （n=55）. The variation in δ^13Corg values in these two sediment cores indicate different sources of organic matter, The relatively high 6~3Corg values in IIL9 are in accordance with a source from algae, while the low δ^13Corg values in IIL1 evince significant influence from penguin guano with algae as the secondary source. Compared with the reference data from other high-latitude lake sediments and plants, the δ^13Corg values in IIL9 were extremely high, a result likely related to intense competition for CO2 assimilation among algal species during the growing season in this relatively shallow pond. These results indicate that sedimentary δ^13Corg is a reliable proxy for paleo-primary productivity in ponds at Inexpressible Island.
文摘The indices related to sedimentary pyrite are widely used in paleo-environmental studies; however its application principles and flaws have not been presented in detail so far,therefore it is necessary to review the controlling factors of them. In this study the authors described the application principles in detail,including pyrite morphology,C/S ratio,DOP,size distribution,sulfur isotope,and further discussed the C-S-Fe system in oil shale in Meihe Formation which indicates oxic or suboxic conditions during oil shale deposition. The concentration of TOC and S in the oil shale in Meihe Formation is more than that in background mudstone,and the pyrite formation is limited by sulfate. Therefore studying the indices related to pyrite proves to be of great importance.
文摘Combined methods for mineralogical identifications were used to characterise the clay deposits within the Lower Benue Trough of Nigeria to interpret paleo-environmental conditions,the paleoclimatic significance of the trough,and effects of weathering on the minerals as factors that favour its deposition/accumulation within the trough which host other important industrial minerals like coal,barite,limestone etc.Bulk-sample random-powder XRD data and data for clay fractions deposited onto zero-background quartz plates were measured.The samples contained kaolinite,vermiculite,and traces of smectite,and the non-clay phases included quartz,microcline,and muscovite.All samples were unaffected after glycolation,confirming the absence of significant smectite.Muscovite was characterized by the nature of its 10Åbasal peak with a width of<0.10°2θ,which was very sharp.DTA/TGA results support the presence of kaolinite,and the characteristic kaolinite O-H,Al-OH,Si-OH and Si-O-Al FTIR bands also confirmed its presence.Vermicular and book-like morphologies were observed under the SEM,typical of kaolinitic clay from in situ alteration.High kaolinite abundance in these sediments is consistent with intense weathering of parent rocks rich in Al under wet/tropical paleo-climatic conditions with fresh and/or brackish water conditions in a continental setting.The variety of observed morphologies suggests that the deposits suffered more of chemical weathering.The clay deposits in Lower Benue Trough are quartz-rich,kaolinitic and derived from the chemical weathering of Al-rich source rocks.
基金Under the auspices of the National Natural Science Foundation of China (49771075) and Testing Foundation by the Modern Analysis
文摘Using five group dating of the fossil by Uranium series age method shows that the age of Nanjing Homo Erectus is between 280－ 430 ka B. P. Combining with the analysis of fossil mammalian form Stegodon, Sus.Lydekkeri Zdansly, M.pachyosteus Young, P.grayi Zdansky and E.SanmeniensisTeilhard et Pive teau, which are located in the same stratum, the authors thinks that the Nanjing Homo Erectus may have lived in the late Mid Pleistocene (about 350 ka B.P.). Based upon the spores and pollen in the cave sediments of the area, we can find that most of spores and pollen are subtropical and warm temperature types. For instance, broad leaf trees which are fond of warm climate, including Cunning hamia, Jsuga and Pinus ,as well as Morus, Carpinus and Ptendium. Among the above spores and pollen, only Tsuga,Liquidambar, Betula,Ulmus and Salix are the remainders of Humid hot environment from the Tertiary period. Above evidences illustrate that the living environment of the Nanjing Homo Erectus not only was not cloder but also was not drier than the Peking Man’s. It could be said that dry climate and the ice age of the Mid Pleistocene didn’t undergo this area.As for the manner of the Homo Erectus’s making stone artifact and using fire, because now we have not found the evidence of the stone artifact and the ash, the futher excavation to the talus of the Huludong cave should be needed.
基金supported by the Certificate of China Postdoctoral Science Foundation (Nos. 2017T100523, 2015M582165)the National Science and Technology Special Fund (Nos. 2016ZX05006-007, 2016ZX05006-003)+3 种基金the National Natural Science Foundation of China (Nos. 41602142, 41372107)the Natural Foundation of Shandong Pronvince (No. ZR2016DB16)the Opening Fund of Shandong Province Key Laboratory of Depositional Mineralization & Sedimentary Mineral (No. DMSM2017064)the Fundamental Research Funds for the Central Universities (No. 15CX08001A)
文摘The Paleozoic Wufeng-Longmaxi shale is one of the main horizons for shale gas exploration in Sichuan Basin. Outcrop, core and thin section observations, X-ray diffraction analysis, trace element geochemistry and other methods have been used to understand the sedimentary characteristics and identify hydrocarbon source rocks in suitable sedimentary paleoenvironments in the Wufeng-Longmaxi shale in northern Guizhou Province. The thickness of the Wufeng-Longmaxi Formation ranges from 20 to 200 m and it was mainly deposited on a deep-water shelf. The TOC content is high, up to 5.75%. The main non-organic minerals are detrital quartz and clay minerals, with a little plagioclase feldspar, potassium feldspar, calcite, dolomite and pyrite. There is also biogenic microcrystalline quartz. Six lithofacies have been identified： siliceous shale, clay shale, calcareous shale, silty shale, carbonaceous shale, and muddy siltstone. Using biological Ba, V/（V＋Ni）, TOC, V/Cr, B, Sr/Ba and other indicators, we estimate primary productivity, redox conditions and paleosalinity and show that the early stage of Wufeng-Longmaxi deposition occurred under strong anoxic conditions, high paleosalinity and yielded a high TOC content and an excellent potential shale gas source. The anoxic environment was destroyed at the late stages of Wufeng-Longmaxi deposition, the TOC content decreased, so that it is likely to be a high quality source rock. Organic pores acted as the key reservoir space in the shales, and the pores are mainly mesopose, with most pore diameters less than 20 nm. The siliceous shale has high TOC content and brittle mineral（quartz） content making it an important exploration target for shale oil and gas exploration.
基金National Natural Science Foundation of China,No.41171163No.40971115Foundation of State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,CAS,No.SKLLQG1208
文摘The Yangshao Culture （approx. 6.9-5.5 ka BP） and the Longshan Culture （approx. 4.6-4.0 ka BP） played important roles in Henan＇s Neolithic Period. Due to spatial distribution of the Yangshao cultural sites, they had a river-oriented trend in comparison with those in the Longshan Period. Apart from terrain factors, distribution of the sites in both periods is subject to paleo-environmental changes. The Yangshao Culture originated in Holocene Optimum Period, and the Longshan Culture started in climatic fluctuations prior to Neolithic ending. But the latter owned more sites and wider scopes than the former did. Both the Cultures devel- oped fast in rich rainfall and warm periods, and withered for abrupt cooling events in 5.4 ka BP and 4.0 ka BP respectively. Therefore, the sustainability of Henan＇s Neolithic Cultures is not good as expected. Whilst, the ancient farming acted an irreplaceable part in distribution of human sites, and the need for farming space prompted human sites to expand from the western hilly areas towards the eastern plain of Henan. Moreover, the neighboring cultures poured into Henan and complicated the cultural patterns. Besides, characteristics of the sites in the Erlitou Period suggest that some social factors disturbed the spatial pattern at the end of Neolithic age in Henan.
