Geochemical features of source rocks and oil in saline and freshwater lake environments: A case study in the southwest Qaidam Basin

He, Xin; Lu, Jungang; Li, Wenyan; Zhu, Songbai; Zhao, Liping; Ma, Zhuang; Zhu, Jiang; Han, Mei; Chen, Shijia

doi:10.1016/j.petrol.2022.110948

Cited by 3 publications

(3 citation statements)

References 32 publications

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“…First, changes in water salinity affect the development of microorganisms and algae [8,9]. Secondly, the special stratification of sedimentary water in the saline lake basin will lead to corresponding changes in the temperature, light transmittance, and redox properties of sedimentary water with depth, which is more conducive to the production and preservation of OM [9,10]. Finally, saltwater lake basins have obtained abundant hydrocarbon production [11,12], confirming good research prospects.…”

Section: Introductionmentioning

confidence: 91%

Sedimentary Environment and Organic Matter Enrichment Model of Saline Lake Source Rock in the Linhe Depression, Hetao Basin, China

Shi

et al. 2023

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The well-developed mudstone and gypsum mudstone in the Oligocene Linhe Formation (E3l) in the Hetao Basin are the main source rocks for gypsum. However, the sedimentary environment and organic matter (OM) enrichment factors of E3l are not clear, and this inhibits the prediction of hydrocarbon source rock distribution and resource calculation. Major and trace elements, total organic carbon (TOC), pyrolysis using the Rock-Eval II, and saturated hydrocarbon gas chromatography–mass spectrometry (GC–MS) analyses were performed in this study. The results show that E3l was deposited in brackish water and saline–ultrasaline water, with weak oxidation reduction in an arid and hot environment. Terrestrial input inhibits OM enrichment, while the redox, paleosalinity, paleoclimate, and paleoproductivity play a catalytic role. The main controlling factors of the same lithologic source rocks are different: terrestrial input and paleoclimate have a greater impact on mudstone, and the redox and paleosalinity were more favorable to gypsum mudstone. Although the main controlling factors are different for different lithologies, their OM enrichment characteristics are still consistent. The E3l water body was deep, and the contribution of nutrients from terrigenous debris to OM enrichment was less. In addition, the water retention environment changed significantly during the E3l sedimentary period, resulting in fewer nutrients, which limited the improvement of surface water paleoproductivity. The arid climate increased water evaporation and salinity, which to some extent prevented consumption and decomposition. Weak oxidation-reduction fluctuations and the stratification of the water body were obvious, and this was not only conducive to the enrichment of OM but also to its preservation.

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Section: Introductionmentioning

confidence: 91%

Sedimentary Environment and Organic Matter Enrichment Model of Saline Lake Source Rock in the Linhe Depression, Hetao Basin, China

Shi

et al. 2023

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“…Spanning a cumulative area of roughly 120,000 km 2 , 29 the basin exhibits a bifurcated morphology, consisting of a more expansive western segment and a comparatively constricted eastern sector, jointly configuring a triangular geometry. 30 2.2. Dalangtan Playa.…”

Section: Sampling Sitesmentioning

confidence: 99%

“…The Qaidam Basin, positioned in the northeastern sector of the Tibetan Plateau within the coordinates of 90°16′–99°16′E longitude and 35°00′–39°20′N latitude, represents an endorheic basin circumscribed by notable mountain ranges including the Kunlun Mountains to the south, the Altyn Mountains to the west, and the Qilian Mountains to the northeast. Spanning a cumulative area of roughly 120,000 km 2 , the basin exhibits a bifurcated morphology, consisting of a more expansive western segment and a comparatively constricted eastern sector, jointly configuring a triangular geometry …”

Section: Sampling Sitesmentioning

confidence: 99%

Hygroscopic Properties of Plateau Surface Salts: Insights from Chemical Composition and Isotope Signatures

Hao,

Qiu,

et al. 2024

ACS Earth Space Chem.

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Evaporite salts from saline lakes and playas play active roles in the atmospheric cycles and the climate system, especially in the context of changing climate. This study investigates the chemical, isotopic, and hygroscopic characteristics of surface salt samples from two saline lakes, i.e., Mang’ai and Dalangtan (MA and DLT), in the Qaidam Basin. Samples from both lakes shared similar ionic compositions, with brines rich in Cl–, Mg2+, and Na+, and lakebed salts being primarily NaCl-based. Disparities in the composition between MA and DLT crust salts were observed. Isotopic analyses revealed consistent δ34S values within samples from a single site, hinting at a common origin. The sulfur source for the MA saline lake likely arises from nearby freshwater inflows and atmospheric deposits. The δ37Cl values varied by sample type, with solid samples typically exhibiting higher values than brines, attributed to 37Cl depletion during precipitation. Ionic composition largely determines hygroscopic properties. While brines started moisture absorption around 40% relative humidity (RH), lakebed salts commenced at 70% RH. The DLT playa salt, enriched in Na2SO4, demonstrated a unique behavior, responding significantly only above 80% RH. The layered DLT samples showcased variable hygroscopic behaviors, particularly the early moisture uptake of the topmost layer, despite its ionic similarity to another layer, hinting at molecular or hydration disparities. In conclusion, this investigation unravels the multifaceted relationship between salt evaporites composition and their implications for atmospheric chemistry.

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Paleo-vegetation and paleo-climate characteristics of Cretaceous and Paleogene strata in several typical basins in China: palynological evidence

Chen

et al. 2023

Historical Biology

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Geochemical features of source rocks and oil in saline and freshwater lake environments: A case study in the southwest Qaidam Basin

Cited by 3 publications

References 32 publications

Sedimentary Environment and Organic Matter Enrichment Model of Saline Lake Source Rock in the Linhe Depression, Hetao Basin, China

Sedimentary Environment and Organic Matter Enrichment Model of Saline Lake Source Rock in the Linhe Depression, Hetao Basin, China

Hygroscopic Properties of Plateau Surface Salts: Insights from Chemical Composition and Isotope Signatures

Paleo-vegetation and paleo-climate characteristics of Cretaceous and Paleogene strata in several typical basins in China: palynological evidence

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