Paleoenvironment and Organic Characterization of the Lower Cretaceous Lacustrine Source Rocks in the Erlian Basin: The Influence of Hydrothermal and Volcanic Activity on the Source Rock Quality

Abstract

Lower Cretaceous lacustrine source rocks in the Erlian Basin are highly heterogeneous. It is important to assess and explain these heterogeneities for the reconstruction of paleoenvironments and the prediction of high-quality source rock distributions. In this study, well-logging, organic, and elemental geochemical data were comprehensively analyzed for the source rocks of Member 4 of the Aershan Formation (Fm) and Member 1 of the Tengger Fm in the southern Bayindulan (BNAN), southern Wulanhua (WLHs), Anan, Aer, and southern Wuliyasitai sags of the Erlian Basin. The variability in sedimentary environments, sources of organic matter of the source rocks in different sags, and the influence of hydrothermal and volcanic activity on the source rock quality in the Erlian Basin were assessed. The results reveal that the source rocks can be divided into four types of organic facies (A, B, BC, and C). Organic facies A–B present hydrogen indices (HIs) higher than 400 mg/g and are mainly composed of mudstone and thick (average thickness >50 m) dolomitic mudstone, with biomarkers characterized by a Pr/Ph ratio lower than 1.0, a gammacerane/C30 hopane (Gam/C30H) ratio higher than 0.2, and a C19 tricyclic terpane/C23 tricyclic terpane (C19/C23TT) ratio lower than 0.6. Organic facies BC–C are composed of mudstone with an HI < 400 mg/g, with biomarkers characterized by a Pr/Ph ratio higher than 0.8, a Gam/C30H ratio lower than 0.2, a C19/C23TT ratio higher than 0.6, and a sterane/hopane ratio lower than 0.4. Dolomitic mudstone belonging to organic facies A–B is mainly developed in the BNAN, WLHs, and Anan sag and is characterized by a fault-controlled distribution in the sag, a right-declined rare earth element pattern, and an enrichment in the elements of Ba, Cu, Zn, Fe, and Ni. The genesis of high HI dolomitic mudstone is associated with hydrothermal and volcanic activity because the hydrothermal fluid or hydrolysis of volcanic ash result in increasing input of reducing gas and soluble nutrient ions, thus promoting the formation of anoxic and saline Cretaceous lakes with high primary productivity.

Paleoenvironmental Settings of the Soma Coal Basin (Turkey): Insights from Maceral Data, Biomarker, and Carbon Isotopic Composition

“…(a) Plot of HI-Tmax, (b) plot of HI-Ro, (c) plot of BI-Tmax, (d) plot of BI-Ro, (e) plot of QI-Tmax, (f) plot of QI-Ro for Soma-Manisa samples. (adapted with permission from ref ( 37 ). Copyright 2023 ACS., 32 , 37 , 38 )…”

Design of hydrogen energy storage frequency modulation method based on primary frequency modulation of power grid

“…Compared with other energy storage methods, hydrogen energy storage has the following four obvious advantages: 1 in the new energy absorption, the advantages of hydrogen storage over other types of energy storage in terms of discharge time (hours to quarters) and capacity scale (100GW) are obvious,in terms of economies of scale of energy storage, as storage time increases [5][6][7][8] , as the marginal value of energy storage systems decreases, the total affordable cost will also decrease, with the cost of large-scale hydrogen storage being an order of magnitude lower than that of electricity storage, hydrogen storage can be carried out by means of long-tube trailers, pipeline transmission, natural gas mixing with hydrogen [9][10][11][12][13][14][15] , ultra-high voltage transmission-hydrogen production at the receiving end and liquid ammonia, etc. , compared with large-scale energy storage technologies such as pumped storage and Compressed air storage, hydrogen storage does not require specific geographical conditions and does not destroy the ecological environment as depicted is table 1.…”