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通过对柴达木盆地狮子沟地区膏盐岩的岩石学及纵向和横向的分布和发育特征进行研究,探讨该区膏盐岩的沉积环境和成岩条件,总结成因模式。研究发现,狮子沟地区膏盐岩层发育在内陆咸化湖半深湖—深湖相中,该时期处于温度由炎热向温暖转变,半干旱向干旱过渡的古气候环境。狮子沟地区膏盐岩纵向上具有4种沉积序列,横向上与砂岩呈“此消彼长”的关系,与泥岩呈“同增同涨”的关系。该区膏盐岩沉积的成因模式为“深水成盐”模式。在渐新世(E3),地下深部热卤水通过处于活动期的深大断裂上涌,盐类物质在狮子沟地区遇冷过饱和,快速堆积成岩。
The petrological, vertical and horizontal distribution and development characteristics of gypsum salt rock in Shizigou area of Qaidam basin are studied. The sedimentary environment and diagenesis conditions of gypsum salt rock in this area are discussed, and the genesis pattern is summarized. The study found that gypsum rock formation in the Shizigou area develops in the semi-deep lacustrine-lacustrine facies of inland salinized lakes during the transition from warm to warm and semi-arid to semi-arid climate. The gypsum salt rocks in the Shizigou area have four sedimentary sequences longitudinally, which are related to sandstone in the horizontal direction and have the relationship of “increasing with increasing” with mudstone. The genesis pattern of gypsum salt deposits in this area is “deep water salt formation” mode. During the Oligocene (E3), the deep underground hot brine was surging up through the active faults and the salt materials became supersaturated in the Shizigou area, rapidly dipping into diagenesis.