Climatic and environmental conditions play a pivotal role in the evolution of the biosphere,serving as the primary natural factors influencing biological evolution and the development of human civilization.The study o...Climatic and environmental conditions play a pivotal role in the evolution of the biosphere,serving as the primary natural factors influencing biological evolution and the development of human civilization.The study of the evolution of Earth's habitability primarily revolves around the reconstruction of climatic and oceanic conditions in geohistorical periods,shedding light on their dynamic changes.This paper collates classic geological indicators and geochemical proxies associated with paleoclimatic and oceanic environmental conditions.The latest“big data”analyses and simulations made possible by the availability of previously unimagined massive datasets reveal several key findings:During the early Paleozoic,atmospheric oxygen levels were low,and widespread oceanic anoxia was prevalent;the Devonian era witnessed a greenhouse climate,followed by the Carboniferous ice age characterized by higher oceanic oxidation levels and alkalinity.The latest Paleozoic deglaciation occurred under high pCO_(2) conditions,extending into much of the Mesozoic and early Cenozoic,marked by multiple hyperthermal and anoxia expansion events,until the resurgence of global glaciation in the middle-late stages of the Cenozoic,ultimately bringing environmental and climatic conditions closer to modern levels.By correlating the aforementioned long-term trends with major geological events,we can delineate the co-evolution of paleoclimate and oceanic environments in tandem with the development of Tethys tectonics as follows.(1)During the Proto-Tethys stage,global paleo-elevations were relatively low,and atmospheric oxygen levels were also relatively modest.Despite the occurrence of significant tectonic movements that led to noticeable transgressive-regressive cycles,their effects on climate and oceanic environments were somewhat limited due to the relatively weak interactions.(2)The emergence of the Paleo-Tethys was a significant event that coincided with the formation of the supercontinent Pangaea.Intensive orogenic movements during this 展开更多
The paleo-temperature evolution of Sinian reservoir of Anping （安平） 1 well was rebuilt by taking the method of apatite fission track and Easy%Ro model. The result of apatite fission track determines the accurate bu...The paleo-temperature evolution of Sinian reservoir of Anping （安平） 1 well was rebuilt by taking the method of apatite fission track and Easy%Ro model. The result of apatite fission track determines the accurate burial history and overcomes the flaw that the vitrinite reflectance is taken as paleo-temperature indicator simply. The authors used the laser Raman technique to analyze the methane present in the calcite and quartz fluid inclusions of Sinian reservoir, finding that the methane is water soluble gas. The authors also simulated the paleo-pressure of fluid inclusion by using PVTsim software and finally worked out the methane solubility in water.展开更多
In the glacial cycles, a marginal sea may display its 'amplifying effect' in environmental changes. An example is the South China Sea (SCS), where the glacial/interglacial contrast of winter sea surface temper...In the glacial cycles, a marginal sea may display its 'amplifying effect' in environmental changes. An example is the South China Sea (SCS), where the glacial/interglacial contrast of winter sea surface temperature (SST) reaches 6—9℃, far exceeding that at similar latitudes in the Pacific. We speculated that such an 'amplifying effect' of SCS must be related to a radical, reorganization of the surface circulation during glacial period, but this is to be tested and verified. Numerical simulation is one way to test it.展开更多
Carbonate clumped isotope(Δ47)is a new and reliable geothermometer.Endogenic carbonates in lake sediments are good archives to reconstruct lake water temperature using clumped isotope thermometry.However,applications...Carbonate clumped isotope(Δ47)is a new and reliable geothermometer.Endogenic carbonates in lake sediments are good archives to reconstruct lake water temperature using clumped isotope thermometry.However,applications of carbonate clumped isotope thermometry to lacustrine carbonates are still scarce because the existed organic and/or sulfur contaminants in such samples interfere with clumped isotope analysis and cause notable temperature biases.Therefore,exploring an effective way to remove contamination is a prerequisite to widely applying carbonate clumped isotope thermometry to lake sediments.By pretreating fine-grained endogenic carbonates from Dali lake sediments with hydrogen peroxide of different concentrations for different lengths of time,we conducted a series of conditional experiments to seek the optimal pretreatment condition for clumped isotope analysis.Δ47,Δ48 offset and 49 parameter were obtained from clumped isotope measurements to assess the effect of contamination removal.Results showed that untreated samples("0%-0")had a very high 49 parameter.After the treatment with hydrogen peroxide,the 49 parameter was significantly reduced while theΔ48 offset evidently increased.TheΔ47,Δ48 offset and 49 parameter of samples pretreated under different conditions showed significant variability,even though the measuredΔ47 temperatures changed within a relatively narrow range(i.e.,from 17.0±1.3 to 22.8±1.6°C).Among various treated samples,the sample"3%-8"yielded a smallerΔ48 offset and 49 parameter,and lowerΔ47 temperature of 17.0±1.3°C.Therefore,"reacting with 3%hydrogen peroxide for 8 h"was suggested to be the optimal condition for removing contaminants from lacustrine endogenic carbonates prior to clumped isotope analysis.At the time when the pretreatment condition was too intense(i.e.,H2O2 concentration>3%and/or reaction time>8 h),secondary contaminants might have been generated in the closed reaction system,whose ultimately transformed state may interfere with masses 47,48.Using the optimal p展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.92155201,42272361)China Geological Survey (The Establishment of Chinese Stratigraphic Standards Project)。
文摘Climatic and environmental conditions play a pivotal role in the evolution of the biosphere,serving as the primary natural factors influencing biological evolution and the development of human civilization.The study of the evolution of Earth's habitability primarily revolves around the reconstruction of climatic and oceanic conditions in geohistorical periods,shedding light on their dynamic changes.This paper collates classic geological indicators and geochemical proxies associated with paleoclimatic and oceanic environmental conditions.The latest“big data”analyses and simulations made possible by the availability of previously unimagined massive datasets reveal several key findings:During the early Paleozoic,atmospheric oxygen levels were low,and widespread oceanic anoxia was prevalent;the Devonian era witnessed a greenhouse climate,followed by the Carboniferous ice age characterized by higher oceanic oxidation levels and alkalinity.The latest Paleozoic deglaciation occurred under high pCO_(2) conditions,extending into much of the Mesozoic and early Cenozoic,marked by multiple hyperthermal and anoxia expansion events,until the resurgence of global glaciation in the middle-late stages of the Cenozoic,ultimately bringing environmental and climatic conditions closer to modern levels.By correlating the aforementioned long-term trends with major geological events,we can delineate the co-evolution of paleoclimate and oceanic environments in tandem with the development of Tethys tectonics as follows.(1)During the Proto-Tethys stage,global paleo-elevations were relatively low,and atmospheric oxygen levels were also relatively modest.Despite the occurrence of significant tectonic movements that led to noticeable transgressive-regressive cycles,their effects on climate and oceanic environments were somewhat limited due to the relatively weak interactions.(2)The emergence of the Paleo-Tethys was a significant event that coincided with the formation of the supercontinent Pangaea.Intensive orogenic movements during this
基金supported by the National Basic Research Program of China (No. 2005CB422106)
文摘The paleo-temperature evolution of Sinian reservoir of Anping （安平） 1 well was rebuilt by taking the method of apatite fission track and Easy%Ro model. The result of apatite fission track determines the accurate burial history and overcomes the flaw that the vitrinite reflectance is taken as paleo-temperature indicator simply. The authors used the laser Raman technique to analyze the methane present in the calcite and quartz fluid inclusions of Sinian reservoir, finding that the methane is water soluble gas. The authors also simulated the paleo-pressure of fluid inclusion by using PVTsim software and finally worked out the methane solubility in water.
基金the National Natural Science Foundation of China and the National Key Laboratory, LASG.
文摘In the glacial cycles, a marginal sea may display its 'amplifying effect' in environmental changes. An example is the South China Sea (SCS), where the glacial/interglacial contrast of winter sea surface temperature (SST) reaches 6—9℃, far exceeding that at similar latitudes in the Pacific. We speculated that such an 'amplifying effect' of SCS must be related to a radical, reorganization of the surface circulation during glacial period, but this is to be tested and verified. Numerical simulation is one way to test it.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grants Nos.XDA19050104 and XDB26000000)the National Key R&D Program of China(Grant No.2017YFA0603400)+1 种基金the National Natural Science Foundation of China(Grants Nos.41931181&41672166)the Key Research Program of the Institute of Geology&Geophysics,CAS(Grant No.IGGCAS-201905)。
文摘Carbonate clumped isotope(Δ47)is a new and reliable geothermometer.Endogenic carbonates in lake sediments are good archives to reconstruct lake water temperature using clumped isotope thermometry.However,applications of carbonate clumped isotope thermometry to lacustrine carbonates are still scarce because the existed organic and/or sulfur contaminants in such samples interfere with clumped isotope analysis and cause notable temperature biases.Therefore,exploring an effective way to remove contamination is a prerequisite to widely applying carbonate clumped isotope thermometry to lake sediments.By pretreating fine-grained endogenic carbonates from Dali lake sediments with hydrogen peroxide of different concentrations for different lengths of time,we conducted a series of conditional experiments to seek the optimal pretreatment condition for clumped isotope analysis.Δ47,Δ48 offset and 49 parameter were obtained from clumped isotope measurements to assess the effect of contamination removal.Results showed that untreated samples("0%-0")had a very high 49 parameter.After the treatment with hydrogen peroxide,the 49 parameter was significantly reduced while theΔ48 offset evidently increased.TheΔ47,Δ48 offset and 49 parameter of samples pretreated under different conditions showed significant variability,even though the measuredΔ47 temperatures changed within a relatively narrow range(i.e.,from 17.0±1.3 to 22.8±1.6°C).Among various treated samples,the sample"3%-8"yielded a smallerΔ48 offset and 49 parameter,and lowerΔ47 temperature of 17.0±1.3°C.Therefore,"reacting with 3%hydrogen peroxide for 8 h"was suggested to be the optimal condition for removing contaminants from lacustrine endogenic carbonates prior to clumped isotope analysis.At the time when the pretreatment condition was too intense(i.e.,H2O2 concentration>3%and/or reaction time>8 h),secondary contaminants might have been generated in the closed reaction system,whose ultimately transformed state may interfere with masses 47,48.Using the optimal p
