海洋地质前沿2025，Vol.41Issue(2)：43-52,10.DOI:10.16028/j.1009-2722.2023.254
渤海湾盆地莱北低凸起明化镇组明下段古环境
Paleoenvironment of Lower Member of Minghuazhen Formation in Laibei low uplift,Bohai Bay Basin
摘要
Abstract
The characteristics of ancient sedimentary environment and the geological significance of oil and gas in the Lower Member of Minghuazhen Formation in the Laibei low uplift of the Bohai Bay Basin remain to be clarified.We utilized comprehensively the trace elements and paleontological data and analyzed the climate,salin-ity,redox conditions,and water depth during the time of Minghuazhen Formation to understand the paleoenviron-ment.Results indicate that the abundance of Li,Ga,Sr elements,and the ratios of Sr/Ba and Th/U trace elements,reflect that the sediments were formed in a freshwater environment.Data from the palynological assemblages sensitive to temperature and humidity,the alteration index(CIA)reflecting the weathering intensity of sediment-ary rocks,and the Sr/Cu,Rb/Sr trace element ratios all indicate a warm and cold transition zone.The analysis of cobalt element content suggests that the ancient water depth ranges from 2.10 to 12.75 m,on average of 6.15 m,indicating a shallow water environment.All the contents or ratios of U/Th,V/(V+Ni),V/Cr,Ni/Co,Ce/Ce*,and Eu/Eu* reflect a weak redox environment.The joint working by the ancient climate background,stable geological structures,and gentle terrain favored the development of shallow water deltas,and the structural pattern of altern-ating depressions and uplifts provided a good support for the formation of large-scale oil reservoirs in the Minghuazhen Formation.关键词
莱北低凸起/明化镇组明下段/古盐度/古气候/古水深/氧化-还原条件Key words
Laibei low uplift/Lower Member of Minghuazhen Formation/paleosalinity/paleoclimate/paleowa-ter depth/redox conditions分类
天文与地球科学引用本文复制引用
李超,廖新武,郭诚,赵大林,李扬..渤海湾盆地莱北低凸起明化镇组明下段古环境[J].海洋地质前沿,2025,41(2):43-52,10.基金项目
中海石油(中国)有限公司重大科研项目"海上油田大幅提高采收率关键技术"(KJGG2021-0505) （中国）
