Compared with the measureable but limited K isotope variation in geological samples,biological samples have much larger variations in δ^41 values：from-1.3‰ to＋1.1‰ relative to the international K standard NIST SR...Compared with the measureable but limited K isotope variation in geological samples,biological samples have much larger variations in δ^41 values：from-1.3‰ to＋1.1‰ relative to the international K standard NIST SRM 3141a.Notably,higher plants generally have δ^41 values that are lower than igneous rocks,whereas sea plants（algae）have δ^41 values that are higher than seawater;the range in δ^41K values of plants encompasses the δ^41 values of both igneous rocks and seawater.Plant cells utilize different K uptake mechanisms in response to highand low-K conditions.In a low-K environment,plant cells use energy-consuming ion pumps for active uptake of K;plant cells in high-K environments use non-energy-consuming ion channels.Based on these facts and on K isotope data from sea and land plants,it is hypothesized that the different K uptake mechanisms are accompanied by distinct K isotope fractionation behaviors or vital effects.The enrichment of light K isotopes in terrestrial plants could be attributed to preferential transport of isotopically light K in the energy-consuming active uptake process by K ion pumps in the membranes of plant root cells.On the other hand,the enrichment of heavy K isotopes in algae may be caused by a combination of the lack of K isotope fractionation during K uptake from seawater via ion channels and the preferential efflux of light K isotopes across the cell membrane back to the seawater.The large variation of K isotope compositions in biological samples therefore may reflect the diversity of isotopic vital effects for K in organisms,which implies the great potential of K isotopes in biogeochemical studies.展开更多
Chemical weathering of rocks and minerals alters the geochemical compositions of the lithosphere,hydrosphere,and atmosphere over time,regulating Earth’s surface temperature by consuming atmospheric CO_(2) so as to su...Chemical weathering of rocks and minerals alters the geochemical compositions of the lithosphere,hydrosphere,and atmosphere over time,regulating Earth’s surface temperature by consuming atmospheric CO_(2) so as to sustain our habitable planet.As the most mobile species in the processes of chemical weathering,cations are thought to be robust geochemical tracers of chemical weathering.Over the past decades,numerous tracers have been proposed for monitoring chemical weathering,mainly focusing on the contents and ratios of cations.Because of the difference from the properties of cations,information that they provide on chemical weathering over different timescales can be inconsistent or even false,such that some avenues of research have reached an impasse.By virtue of the identical properties of isotopes of the same element and the high-dimensional information that they carry,the stable isotopes of cations have been employed to objectively trace chemical weathering processes,which has become a rapidly developing direction of chemical weathering research.In this review,we summarize the progress made in tracing chemical weathering via the stable cation isotopes(δ^(7) Li,δ^(26) Mg,δ^(41) K,δ^(44/40) Ca,δ^(87/85) Rb,δ^(88/86) Sr,and δ^(138/134) Ba)and point out the development trends and persisting problems.After considering the virtues and deficiencies of various cation isotopes,we recommend the combination of multiple cation isotopes that complement and support one another as the future direction to obtain the reliable information on each process of chemical weathering.This should provide the most effective method for objectively tracing chemical weathering,thereby deepening our understanding of the regulatory mechanisms influencing the habitable surficial temperature.展开更多
Deciphering hydrocarbon generation and accumulation stage is of significance to understand oil and gas evolution and seek exploration targets.Taking the Upper Paleozoic buried-hills in the Huanghua Depression,Bohai Ba...Deciphering hydrocarbon generation and accumulation stage is of significance to understand oil and gas evolution and seek exploration targets.Taking the Upper Paleozoic buried-hills in the Huanghua Depression,Bohai Bay Basin,as a case study,hydrocarbon generation environment and detailed accumulation process are revealed by fluid inclusions observations,Laser Raman spectroscopy,Fourier Infrared spectroscopy,and K-Ar isotope measurements.The results show that both oil and gas inclusion were captured in the quartz overgrowth,dissolved feldspar and calcite microfractures,showing blue to dark brown fluoresce.The grains containing oil inclusions index(GOI)of oil,oil&gas and gas being 25%,65%,and 10%and the inclusions with abundant methyl groups and short chains,both indicate high thermal maturity.One series of fluids inclusion is generally observed,evidenced by the concentrated homogenization temperature of 135-145℃and salinity of 3%-15 w.t.%NaCl equiv,indicating one primary charging stage.The gas and gas&liquid inclusions mainly contain CH_(4),with also peaks indicating CO_(2)and N_(2.)The Carboniferous and Permian biomarkers show reducing environment with brackish water,with organic matter sources both from marine and continental.The relative content ofααα20RC_(27),ααα20RC_(28),andααα20RC_(29)exhibit source contributions both from algae and higher plants,and mainly of II2 to III kerogen.Both coal derived gas and oil associated hydrocarbons are identified from most of the buried-hills.Combining the fluid homogenization temperature and salinity,as well as the thermal evolution history,the hydrocarbon generated from the Upper Paleozoic was concentrated at the end of the Eocene(40 Ma±),while the beginning of charging is 60 Ma±.The Wumaying Buried-hill is of only coal derived gas and has potential for inner coal measure natural gas exploration.The results provide a detailed understanding of hydrocarbon accumulations in the study area,which can also be reference for improving petroleum exploration efficiency in similar basins.展开更多
基金supported by"1000-talent Program"of China,and National Science Foundation of China(Grant No.41622301)to WL
文摘Compared with the measureable but limited K isotope variation in geological samples,biological samples have much larger variations in δ^41 values：from-1.3‰ to＋1.1‰ relative to the international K standard NIST SRM 3141a.Notably,higher plants generally have δ^41 values that are lower than igneous rocks,whereas sea plants（algae）have δ^41 values that are higher than seawater;the range in δ^41K values of plants encompasses the δ^41 values of both igneous rocks and seawater.Plant cells utilize different K uptake mechanisms in response to highand low-K conditions.In a low-K environment,plant cells use energy-consuming ion pumps for active uptake of K;plant cells in high-K environments use non-energy-consuming ion channels.Based on these facts and on K isotope data from sea and land plants,it is hypothesized that the different K uptake mechanisms are accompanied by distinct K isotope fractionation behaviors or vital effects.The enrichment of light K isotopes in terrestrial plants could be attributed to preferential transport of isotopically light K in the energy-consuming active uptake process by K ion pumps in the membranes of plant root cells.On the other hand,the enrichment of heavy K isotopes in algae may be caused by a combination of the lack of K isotope fractionation during K uptake from seawater via ion channels and the preferential efflux of light K isotopes across the cell membrane back to the seawater.The large variation of K isotope compositions in biological samples therefore may reflect the diversity of isotopic vital effects for K in organisms,which implies the great potential of K isotopes in biogeochemical studies.
基金supported by the National Natural Science Foundation of China(42221003,41930864,42103055,42373054)the National Key Research and Development Program of China(2022YFF0800101).
文摘Chemical weathering of rocks and minerals alters the geochemical compositions of the lithosphere,hydrosphere,and atmosphere over time,regulating Earth’s surface temperature by consuming atmospheric CO_(2) so as to sustain our habitable planet.As the most mobile species in the processes of chemical weathering,cations are thought to be robust geochemical tracers of chemical weathering.Over the past decades,numerous tracers have been proposed for monitoring chemical weathering,mainly focusing on the contents and ratios of cations.Because of the difference from the properties of cations,information that they provide on chemical weathering over different timescales can be inconsistent or even false,such that some avenues of research have reached an impasse.By virtue of the identical properties of isotopes of the same element and the high-dimensional information that they carry,the stable isotopes of cations have been employed to objectively trace chemical weathering processes,which has become a rapidly developing direction of chemical weathering research.In this review,we summarize the progress made in tracing chemical weathering via the stable cation isotopes(δ^(7) Li,δ^(26) Mg,δ^(41) K,δ^(44/40) Ca,δ^(87/85) Rb,δ^(88/86) Sr,and δ^(138/134) Ba)and point out the development trends and persisting problems.After considering the virtues and deficiencies of various cation isotopes,we recommend the combination of multiple cation isotopes that complement and support one another as the future direction to obtain the reliable information on each process of chemical weathering.This should provide the most effective method for objectively tracing chemical weathering,thereby deepening our understanding of the regulatory mechanisms influencing the habitable surficial temperature.
基金supported by the National Natural Science Foundation of China(Grant No.42072194,U1910205)the Fundamental Research Funds for the Central Universities(800015Z1190,2021YJSDC02).
文摘Deciphering hydrocarbon generation and accumulation stage is of significance to understand oil and gas evolution and seek exploration targets.Taking the Upper Paleozoic buried-hills in the Huanghua Depression,Bohai Bay Basin,as a case study,hydrocarbon generation environment and detailed accumulation process are revealed by fluid inclusions observations,Laser Raman spectroscopy,Fourier Infrared spectroscopy,and K-Ar isotope measurements.The results show that both oil and gas inclusion were captured in the quartz overgrowth,dissolved feldspar and calcite microfractures,showing blue to dark brown fluoresce.The grains containing oil inclusions index(GOI)of oil,oil&gas and gas being 25%,65%,and 10%and the inclusions with abundant methyl groups and short chains,both indicate high thermal maturity.One series of fluids inclusion is generally observed,evidenced by the concentrated homogenization temperature of 135-145℃and salinity of 3%-15 w.t.%NaCl equiv,indicating one primary charging stage.The gas and gas&liquid inclusions mainly contain CH_(4),with also peaks indicating CO_(2)and N_(2.)The Carboniferous and Permian biomarkers show reducing environment with brackish water,with organic matter sources both from marine and continental.The relative content ofααα20RC_(27),ααα20RC_(28),andααα20RC_(29)exhibit source contributions both from algae and higher plants,and mainly of II2 to III kerogen.Both coal derived gas and oil associated hydrocarbons are identified from most of the buried-hills.Combining the fluid homogenization temperature and salinity,as well as the thermal evolution history,the hydrocarbon generated from the Upper Paleozoic was concentrated at the end of the Eocene(40 Ma±),while the beginning of charging is 60 Ma±.The Wumaying Buried-hill is of only coal derived gas and has potential for inner coal measure natural gas exploration.The results provide a detailed understanding of hydrocarbon accumulations in the study area,which can also be reference for improving petroleum exploration efficiency in similar basins.
