柴达木盆地新生代湖相叠层石沉积序列及古环境意义

发布时间：2019-02-17 13:55

【摘要】：气候、沉积环境和湖平面的演变直接或间接地影响湖相叠层石的生长,因而叠层石的出现可以作为此三者变化的判别标志。通过对比研究柴达木盆地西部地区西岔沟、长尾台两条新生代陆相地层剖面中近10个湖相叠层石的发育层位、垂向沉积序列,表明叠层石主要发育于新生代两个气候温暖湿润的高湖面时期,而且叠层石沉积亦同时出现在青藏高原其他邻近陆相新生代盆地,显示区域性的大规模异常湿润性气候,以强蒸发和强降水的交替为特征;划分出的4种含叠层石基本沉积序列中,叠层石可在泥岩或砂砾岩硬底上生长,含叠层石灰岩层之上通常是细粒碎屑沉积或间断面,这暗示了叠层石的生长出现在滨湖、浅湖相次级湖泛面附近,或指示湖水的突然加深。
[Abstract]:Climate, sedimentary environment and the evolution of lake plane directly or indirectly affect the growth of lake stromatolite, so the appearance of stromatolite can be used as the discriminant of these three changes. Based on a comparative study of the development and vertical sedimentary sequences of nearly 10 lacustrine stromatolites in two Cenozoic continental stratigraphic profiles in the western Qaidam Basin, Xichagou and Changweitai, The results show that stromatolites mainly developed in two high lake periods with warm and humid climate in Cenozoic, and stromatolites deposits also appeared in other adjacent continental Cenozoic basins on the Qinghai-Xizang Plateau, indicating a large scale abnormal humid climate. It is characterized by the alternation of strong evaporation and heavy precipitation. Among the four basic sedimentary sequences of stromatolites, stromatolites can grow on the hard bottom of mudstone or sandy conglomerate, and there are usually fine clastic deposits or discontinuities above the laminated limestone layers, which implies that stromatolites are growing in the lakeshore. Shallow lacustrine secondary lake surface near, or indicate lake water suddenly deepens.
【作者单位】：成都理工大学沉积地质研究院;Georg-August-Universit釨t
【基金】：国家自然科学基金青年基金项目“东昆仑山新生代构造隆升的碎屑矿物裂变径迹记录”(41402099)
【分类号】：P512.2;P534.6

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