成都理工大学学报（自然科学版）2018，Vol.45Issue(3)：268-281,14.DOI:10.3969/j.issn.1671-9727.2018.03.02
川北旺苍地区茅口组地球化学特征及古环境记录
Geochemical characteristics and palaeo-environmental implication of Middle Permian Maokou Formation in Wangcang region,Sichuan Basin,China
摘要
Abstract
The palaeo-environment revealed by carbonate rocks of middle Permian Maokou Formation in Wangcang region is discussed on the basis of analysis of the geochemical characteristics.It shows that theδ13 C andδ18 O of 32 samples are stable without any linear relationship.These parameters all meetδ18 O>-6‰,Mn/Sr≤0.6,Fe/Sr<3,MgO/CaO<0.12,and are unlikely influenced by late diagenetic alteration,so they can be used as reliable targets for paleo-environmental analysis.The contents of terrigenous elements,Al2 O3 ,TiO2 ,are low and positively correlated,and the degree of REE differentiation is obviously weak.There is a strong positive correlation between ∑ REE and∑(Al2 O3 +TiO2 ).Vertically,∑ (Al2 O3 + TiO2 )and ∑ REE have same variation tendency,but variation of the ancient water depth index Sr/Ba, 1000×(Sr/Ca) has opposite trend. The characteristic ratios of MgO/CaO,Sr/Ba,1000×(Sr/Ca),U/Al,V/Al,Cr/Al,Co/Al,U/Th and V/(V+Ni)indicate that the terrigenous materials are insufficient during the depositional period and the REE content is mainly influenced by terrigenous supply.Analysis reveals that paleo-oceanic temperature is between 14.98～26.55℃,and the salinity of ancient seawater is in the range of 132.3～135.2.It conforms that the carbonate successions in the study area are deposited in an dysaerobic-anaerobic environment, characteristic of relatively high sea level, small range of water depth variation,and three transgression and regression cycles.The trace element evolution curves and the corresponding lithofacies assemblage can be used as the basis of stratigraphic division.关键词
中二叠统/茅口组/地球化学/古环境/旺苍地区Key words
middle Permian/Maokou Formation/geochemistry/palaeo-environment/Wangcang area分类
天文与地球科学引用本文复制引用
李乾,徐胜林,陈洪德,林良彪,杨帅,余瑜,孙逢瑞,董翼昕,邓翔..川北旺苍地区茅口组地球化学特征及古环境记录[J].成都理工大学学报（自然科学版）,2018,45(3):268-281,14.基金项目
国家自然科学基金青年科学基金项目(41602107) （41602107）
成都理工大学中青年骨干教师培养计划项目(JXGG201537,JXGG201538). （JXGG201537,JXGG201538）
