四川盆地海相三叠系硬石膏和盐卤水的硫同位素组成及意义

四川盆地下、中三叠统硬石膏和盐卤水广布，通过对采集于不同地段不同层位各具代表性的硬石膏、石膏和盐卤水的２４４件样品的分析，可见其同层位硫同位素组成稳定，δ３４Ｓ自下而上具阶梯状递减轻化的趋势，与已知全球海相三叠系硫同位素组成有明显差异。这种硫同位素分布规律对地层划分和对比、蒸发岩形成环境的判断、研究卤水产层和成因、掌握蒸发岩咸化发展方向及预测找钾工作等的意义不容忽视。

ANHYDRITE AND SALT BRINE OF TRISSIC SEQUENCE IN SICHUAN BASIN: COMPOSITION AND IMPLICATION OF SULFUR ISOTOPE

Sichuan basin is known for widespread anhydrite and salt brine in the low and middle Trissic rocks. Altogether 244 samples were collected from anhydrite, gypsum and salt brine beds, properly representative of the related sectors and levels. Their isotopic analysis reveals that sulfur isotopes are composed insistently at a single level and that δ 34 S shows a step by step trend to light isotopic group from down to up, clearly differing from that of the known sulfur isotopic compositions of the global marine Trissic sequences. This difference will contribute much to dividing and correlating stratigraphy, understanding evaporite forming conditions, recognizing location and origination of brines, tracing their evolutions and eventually guiding potash hunting.