吉林省南部下元古界集安群地质特征与沉积期古环境分析

根据集安群地质特征,岩石化学,稳定同位素特征分析认为:蚂蚁河组沉积期古环境为强氧化泻湖相;荒岔沟组沉积期为强还原的泻湖相、大东岔组沉积期为开阔正常浅海潮坪相。集安群从发生发展到结束古环境演化规律是:构造上,由优地槽向冒地槽演化,气候上由炎热向温湿演化;古地理环境从有障壁的局限海变为无障壁的开阔海;从咸化海向正常海,从泻湖相向潮坪相转化。

THE GEOLOGICAL FEATURES OF THE LOWER, PROTEROZOIC JI'AN GROUP IN SOUTHERN JILIN AND THE PALAEOENVIRONMENTAL ANALYSIS DURING THE DEPOSITION

According to the geological features of the Ji'an Group, petrochemistry, and analysis on the stable isotopic characteristics, it is proposed that the palaeoenvironment of the Mayihe formation belongs to strongly oxidized lagoonal facies, that of the Huangchagou formation, strongly reduced lagoon phase, and that of the Dadongcha formation, tidal-flat facies of general open shallow sea. The regularity of palaeoenvironmental evolution of the Ji'an Group is (from the beginning to the end) that tectonically it is developed to the miogeosyncline from eugeosyncline; it is from hot to warm and humid in climate; it is from the restricted sea with the barriers to the open sea without any barriers, from salized sea to normal sea and from lagoonal facies to tidal flat in palaeogeographical environment.