New insights into the carbon cycle and depositional models of the Eocene saline lake, Jianghan basin, China

Wei, Ren; Ma, Haoran; Jin, Zhijun; Wang, Tianyu; Zhang, Chi; Wang, Yuhan; Dong, Lin

doi:10.1016/j.marpetgeo.2022.106079

Cited by 2 publications

(3 citation statements)

References 72 publications

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“…Recent studies indicate that the mixed sediments in Qian 3 4 section (this study) can be divided into two types: siliciclastic-dominated mixed sediment and carbonate-dominated mixed sediment. These variations are indicative of consistent fluctuations in the overall balance between water inflow/outflow [22]. Therefore, the degree of fluvial input and weathering processes affecting mixed sediments in the Qianjiang region varies across different lithologies.…”

Section: Geological Settingsmentioning

confidence: 94%

“…An increase in the δ 18 O values is indicative of increased evaporation and reduced precipitation, and vice versa [63]. The temperature may also affect δ 18 O, but compared to the changes caused by evaporation and precipitation, the impact of these changes is relatively minor [22]. The δ 18 O values of the 3044-3046 m sediment section are relatively lower than the 3031-3043 m sediment section (Figure 2), which indicates a humid climate with more precipitation.…”

Section: Paleoclimate Characteristicsmentioning

confidence: 99%

“…Recently, there has been a gradual increase in geochemical research focusing on the carbonate constituents in lacustrine carbonate [18][19][20][21]. For instance, carbon and oxygen isotopes in carbonates have been employed to reconstruct ancient environments [22], while Mg isotopes of halite serve as a sensitive indicator for drying and recharging events in terrestrial saline lakes [23]. In addition, there has been corresponding progress on the origin of dolomite in lagoons with higher salinity [24,25].…”

Section: Introductionmentioning

confidence: 99%

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Dynamic Climate Influence on Magnesium Isotope Variation in Saline Lacustrine Dolomite: A Case Study of the Qianjiang Formation, Jianghan Basin

Wang,

Ling,

Wei

et al. 2024

Minerals

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The investigation of magnesium (Mg) isotopes in dolomite has mainly focused on marine dolomite environments, leaving a significant gap in the understanding of their dynamics within lacustrine settings, especially in saline lake basins. In this study, a total of 16 sediment core samples from Well BX-7 in the Qianjiang Depression were sequentially selected for scanning electron microscope observation, whole-rock analysis for major and minor elements, and isotopic measurements including δ18Ocarb, δ13Ccarb, δ26Mgdol, and δ26MgSi. In addition, two intact cores were subjected to detailed analysis on the centimeter scale. Sedimentation models were established to elucidate dolomite formation under contrasting climatic conditions, specifically humid climates with a significant riverine Mg input versus relatively dry conditions with a lower Mg input. Furthermore, a quantitative model was developed to assess the magnesium flux and isotopic mass balance within lacustrine systems, simulating the magnesium isotope variations in lake water under different climatic scenarios. The dolomite sample data at a smaller scale (sampling interval ≈ 3~5 mm) demonstrate a consistent trend with the established model, providing additional confirmation of its reliability. Dolomite precipitated under humid climatic conditions exhibits a lower and relatively stable δ26Mgdol, lower δ18O, and higher CIA, indicating higher river inputs and relatively stable Mg isotope values of lake water controlled by river input. Nevertheless, dolomite formed under relatively dry climatic conditions shows a relatively high δ26Mgdol, higher δ18O, and lower CIA, suggesting reduced river inputs and weathering intensity, as well as relatively high magnesium isotope values of the lake water controlled by dolomite precipitation. This study contributes to the understanding of magnesium isotopes in lacustrine dolomite systems.

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Section: Geological Settingsmentioning

confidence: 94%

Section: Paleoclimate Characteristicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamic Climate Influence on Magnesium Isotope Variation in Saline Lacustrine Dolomite: A Case Study of the Qianjiang Formation, Jianghan Basin

Wang,

Ling,

Wei

et al. 2024

Minerals

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Sulfur Isotope Characteristics in the Qian-34 Section of the Qianjiang Depression and Its Implications for the Paleoenvironment

Wang,

Wei,

Ling

et al. 2024

Minerals

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Pyrite is an important proxy used to reflect the redox state of a sedimentary environment. Currently available studies on pyrite focus on the process of sulfur cycles between an ocean and sediment. However, our understanding of the biogeochemical cycle of sulfur in terrestrial lake basins remains unclear, and the growth patterns of different types of pyrite are poorly understood. In this paper, we used samples from the 34 section of the Qianjiang depression in the Jianghan Basin as direct research objects by combining pyrite and sulfur isotope determination. The one-dimensional diffusion–advection–reaction simulation (1D-DAR) model was applied to simulate the changes in the pyrite content and sulfur isotope values in the sediment. The results show that the sediments in the saline lake basin environment contain a high organic matter content, a high sedimentation rate, and a high H2S diffusion oxidation rate, reflecting the strong reducing background and high productivity of this ancient lake. Sensitivity tests revealed that the organic matter content and H2S diffusion oxidation rate at the sediment–water interface are sensitive to the pyrite content. The sedimentation rate, organic matter content, and sulfate concentration are sensitive to the pyrite’s sulfur isotope values. However, the variation in the active iron content had little effect on the pyrite content or sulfur isotope value.

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New insights into the carbon cycle and depositional models of the Eocene saline lake, Jianghan basin, China

Cited by 2 publications

References 72 publications

Dynamic Climate Influence on Magnesium Isotope Variation in Saline Lacustrine Dolomite: A Case Study of the Qianjiang Formation, Jianghan Basin

Dynamic Climate Influence on Magnesium Isotope Variation in Saline Lacustrine Dolomite: A Case Study of the Qianjiang Formation, Jianghan Basin

Sulfur Isotope Characteristics in the Qian-34 Section of the Qianjiang Depression and Its Implications for the Paleoenvironment

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