摘要
目的分析柴达木盆地第三纪盐湖的沉积环境。方法利用稳定同位素分馏理论及其分析技术,分析了现代青海湖稳定同位素的组成特征,并与柴达木盆地第三纪盐湖的沉积环境特点进行了对比。结果柴达木盆地第三纪咸化湖泊沉积碳酸盐岩中富集δ13C与δ18O,具有较高的Z值,并且大多与海洋碳酸盐岩碳氧同位素区间值重叠,说明第三纪咸化湖泊的盐度与海相相当或高于海水;柴达木盆地硫酸盐的δ34S值大大超过海洋硫酸盐的δ34S值,且在第三纪盐湖的演化过程中具有化学分层特征,在湖盆下部产生了强烈的硫同位素分馏现象,导致较高δ34S值蒸发岩沉积的形成。结论柴达木盆地第三系盐湖沉积地层中可发育较丰富的油气资源。
Aim To analyze Tertiary period sedimentary environment of Qaidamu saline lake.Methods Contrasting Tertiary period sedimentary environment by analyzing stable isotope composition feature of moden times Qaidamu lake based on stable isotope fractionation theory and analyzing technique.Results The carbonate sediments in Qaidamu saline lake are rich in δ^(13)C and δ^(18)O with relatively high Z values, most of which are coincidence with Z values of marine carbonate rocks. The fact shows that the salinity of Tertiary saline lake is equal to or bigger than the one of seawater. Sulfate of Qaidamu Basin is quite rich in δ^(34)S and δ^(34)S value is greatly bigger than the one of ocean sulfate. Conclusion In the evolvement process of tertiary saline lake, there is a character of lamination in chemistry and exists sulfur isotope fractional distillation in the lower of Qaidamu Basin, which results in the forming of evaporation with high δ^(34)S value. Therefore, there may exist quite abundant oil and gas resource in Tertiary saline sediment of Qaidamu Basin.
出处
《西北大学学报（自然科学版）》
CAS
CSCD
北大核心
2005年第3期342-346,共5页
Journal of Northwest University（Natural Science Edition）
基金
中国石油天然气股份有限公司"九五"油气勘探科技工程基金资助项目(9702080302)
关键词
柴达木盆地
第三纪
湖泊沉积物
稳定同位素
同位素分馏
Qaidamu Basin
Tertiary period
lacustrine sediment
stable isotope
isotope fractional distillation
