minerals Article Geochemical Characterization of the Eocene Coal-Bearing Source Rocks, Xihu Sag, East China Sea Shelf Basin, China: Implications for Origin and Depositional Environment of Organic Matter and Hydrocarbon Potential Xiong Cheng 1,2,* , Dujie Hou 1,2,*, Xinhuai Zhou 3, Jinshui Liu 4, Hui Diao 4 and Lin Wei 1,2 1 School of Energy Resources, China University of Geosciences, Beijing 100083, China;
[email protected] 2 Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Accumulation Mechanism, Ministry of Education, Beijing 100083, China 3 Hainan Branch of China National Offshore Oil Corporation, Haikou 570100, China;
[email protected] 4 Shanghai Branch of China National Offshore Oil Corporation, Shanghai 200050, China;
[email protected] (J.L.);
[email protected] (H.D.) * Correspondence:
[email protected] (X.C.);
[email protected] (D.H.) Abstract: Eocene coal-bearing source rocks of the Pinghu Formation from the W-3 well in the western margin of the Xihu Sag, East China Sea Shelf Basin were analyzed using Rock-Eval pyrolysis and gas Citation: Cheng, X.; Hou, D.; Zhou, chromatography–mass spectrometry to investigate the samples’ source of organic matter, depositional X.; Liu, J.; Diao, H.; Wei, L. environment, thermal maturity, and hydrocarbon generative potential. The distribution patterns of Geochemical Characterization of the n-alkanes, isoprenoids and steranes, high Pr/Ph ratios, abundant diterpanes, and the presence of non- Eocene Coal-Bearing Source Rocks, hopanoid triterpanes indicate predominant source input from higher land plants. The contribution of Xihu Sag, East China Sea Shelf Basin, aquatic organic matter was occasionally slightly elevated probably due to a raised water table.