Quantitative geochemical reconstruction of Eocene paleoenvironment in Fushun Basin,northeast ChinaOAEI
The quantitative estimation of key parameters of paleotemperature and paleoprecipitation is crucial for paleoclimate reconstruction.Geochemical data from mod-ern sediments are highly consistent with climate data,and their relationship can provide an important reference for the quantitative reconstruction of the paleoclimate.In this study,detailed inorganic geochemical analysis was carried out using high-precision sampling of the Paleogene(LFD-1 well)Guchengzi,Jijuntun and Xiloutian Formations in the Fushun Basin located in the mid-latitudes of the Northern Hemisphere.The Eocene Guchengzi Formation(54.51–47.8 Ma)and Jijuntun Formation(47.8–41.2 Ma)in the Fushun Basin were found to have been deposited under a humid climate.The lower(41.2–40.1 Ma)and upper(40.1–37.8 Ma)parts of the Xiloutian Formation were character-ized by semiarid and semihumid–semiarid climates,respec-tively,which is very similar to the paleoclimatic information reflected by organic carbon isotopes.The Eocene Thermal Maximum 2(ETM2,~53.7 Ma),Early Eocene Climatic Optimum(EECO,~53.1–46.5 Ma),Eocene Thermal Maxi-mum 3(ETM 3,~52.8 Ma),and Middle Eocene Climatic Optimum(MECO,~40.7–40.1 Ma)events significantly enhanced chemical weathering during these periods.The rapid increase in pCO_(2)concentration leads to an increase in temperature,precipitation,and surface runoff,exhibiting strong chemical weathering.The mean annual temperature(MATa)and mean annual precipitation(MAPa,MAPb,and MAPc)were estimated using parameters,such as the corrosion index without potassium(CIA-K),CaO/Al_(2)O_(3),and(Na_(2)O+K_(2)O)/Al_(2)O_(3).Comparing MAPa,MAPb,and MAPc with the MAP estimated using pollen data,MAPa and MAPb were found to be more sensitive to the climate during high precipitation periods(precipitation>1000 mm,Guchengzi Formation),and the recovered average precipi-tation was similar to MAP.In contrast,MAPc was more sensitive to the climate during low precipitation periods(precipitation<1000 mm,Jijuntun,and Xiloutian Forma-tions),with higher accuracy.To fully consider the influence of soluble inorganic salts Ca^(2+)and Na^(+),multivariate linear equations of CIA-K and CaO/Al_(2)O_(3)with CIA,and CIA-K and CaO/Al_(2)O_(3)with MAP were constructed,namely MAPd and MAPe.The results show that MAPe has the highest per-formance and can be effectively used to estimate the change of paleoprecipitation in Northeast Asia.
Yuanji Li;Pingchang Sun;Qiang Zhang;Junxian Wang;
Department of Safety Engineering,Heilongjiang University of Science and Technology,Harbin 150022,China National Professional Center Lab of Safety Basic Research for Hydrocarbon Gas Pipeline Transportation Network,Harbin 150022,China College of Earth Sciences,Jilin University,Changchun 130061,Jilin,ChinaCollege of Earth Sciences,Jilin University,Changchun 130061,Jilin,ChinaDepartment of Safety Engineering,Heilongjiang University of Science and Technology,Harbin 150022,China National Professional Center Lab of Safety Basic Research for Hydrocarbon Gas Pipeline Transportation Network,Harbin 150022,ChinaBeijing Research Institute of Uranium Geology,Beijing 100029,China
地质学
EoceneFushun BasinMajor elementPaleoclimateGeochemical reconstruction
《Acta Geochimica》 2024 (003)
P.571-587 / 17
the New Era Longjiang Excellent Master’s and Doctoral Dissertations(LJYXL2022-082);Postdoctoral funding from Heilongjiang Province(LBH-Z23030);National Natural Science Foundation of China(U21A201649);the Scientific research start-up funds of Heilongjiang University of Science and Technology;the Supported by the project of Nature Scientific Foundation of Heilongjiang Province(YQ2022E041)。
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