古地理学报2016，Vol.18Issue(6)：1012-1029,18.DOI:10.7605/gdlxb.2016.06.077
准噶尔盆地玛湖凹陷下二叠统风城组含碱层段韵律特征及成因
Characteristics of alkaline layer cycles and origin of the Lower Permian Fengcheng Formation in Mahu sag,Junggar Basin
摘要
Abstract
Ancient Mahu lake was a typical carbonate saline lake in the Early Permian where abun-dant carbonate minerals (mostly with positive ion of sodium)were deposited.Based on the data of major elements,oxygen and carbon isotope,petrology and mineralogy characters of systematic samples of study core section,rhythm characteristics and their mechanism were discussed.The study core section alternated with soda layers and sedimentary tuff layers.Light soda layers are relatively pure nahcolite and sodium, and have major elements characteristics as follows:High content of Na2 O,low content of CaO,MgO, SiO2 and Al2 O3 .Dark sedimentary tuff layers developed white spot shaped minerals of shortite,and have major elements characteristics as follows:Lower content of Na2 O,high content of CaO,MgO,SiO2 and Al2 O3 .Both soda layers and sedimentary tuff layers have high values of δ1 8O and δ1 3C,which indicate that sedimentary water has high salinity during the depositional period of whole layers.Light soda layers have higher δ1 8 O value,which indicate intense evaporation when soda deposited.The study core section can be explained into multiple stages of hot and dry climate and relative humid climate according to the value ofδ1 8O /δ1 3C.Origin of different carbonate minerals formed in different layers could achieve.Dark layers formed when palaeoclimate was warm and humid that water input was more than water output,and shortite crystaled inter-particles when palaeoclimate transformed into hot and dry.When palaeoclimate transformed into hot and dry,calcium ion and magnesium ran out,nahcolite and baking soda crystaled with strong e-vaporation.Frequent changes of palaeoclimate have produced saline cycles of soda layers and sedimentary tuff layers.关键词
准噶尔盆地/玛湖凹陷/风城组/咸化/碳酸盐矿物/成碱机理Key words
Junggar Basin/Mahu sag/Fengcheng Formation/salinization/carbonate mineral/alkaline formation mechanism分类
天文与地球科学引用本文复制引用
余宽宏,操应长,邱隆伟,孙沛沛,杨勇强,曲长胜,万敏..准噶尔盆地玛湖凹陷下二叠统风城组含碱层段韵律特征及成因[J].古地理学报,2016,18(6):1012-1029,18.基金项目
国家重点基础研究发展规划项目（编号2014CB239002），中央高校基本科研业务费专项资金（编号16CX02030A），山东省自然科学基金青年基金项目（编号ZR2014DQ016）和中国石油大学（华东）科研启动基金项目（编号2013004）联合资助。［Co-funded by Na-tional Program on Key Basic Research Project（No．2014CB239002），Fundamental Research Funds for the Central Universities （No．16CX02030A）， Shandong Natural Science Foundation （No．ZR2014DQ016） and Scientific Research Foundation of China University of Petroleum （East China ）（No．2013004）］ （）
