Preliminary Investigation on Depositional Environment of Black Mud in Lower Cretaceous, Zhejiang and Fujian Provinces: Micropaleontology and Organic Geochemical Evidences

Key words: 
• Zhejiang and Fujian provinces

Abstract: Sedimentary rocks of lower Cretaceous widely distribute in volcaniccovered area in Zhejiang and Fujiang provinces, southeast China, and its sedimentary environment that whether it has been influenced by marine water is still controversial. Though carefully observation in outcrops, we have systematically sampled dark sedimentary rocks, including Bantou Formation (K1b) in Fujian province, Shouchang Formation (K1s) and Guantou Formation (K1g) in Zhejiang province. Under microscope, besides high plant, marine fossils such as red algae and brown algae, were found in these samples. Organic geochemistry features, such as lower γ/ C30 hopanoid values (range from 0.11 to 0.18, 0.14 on average) and C30 rearrangement hopanoid, are furthermore to approve the marine influence. Combining with geological background, it is presupposed that it is mainly influenced by paleoPacific.