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湖南西部桑植地区中二叠统栖霞组地层旋回性明显,有机质也呈周期性变化.研究其有机质聚集堆积控制因素将有助于理解海平面变化在富有机碳沉积物形成过程中的作用.选择其中一个旋回作为研究目的层段,通过黄铁矿形态以及地球化学参数有机碳TOC、硫同位素、DOP以及微量元素的研究发现,初级生产力参数Ba、Ni、Cu和Zn的变化与TOC含量的变化一致,有机质聚集堆积主要受海洋表层初级生产力的控制,底部水体氧化还原条件与初级生产力有关.有机质的堆积最终归因于高频相对海平面变化,海平面快速上升带来丰富的营养物质,提高海洋表层生物生产力,海底有机质的分解消耗大量氧气,氧需求量的增加形成底部水体贫氧-厌氧环境.
The Cymbals of the Middle Permian Qixia Formation in the Sangzhi area of western Hunan Province are obviously cyclical, and the organic matter also changes cyclically. It is helpful to understand the role of sea level change in the formation of organic carbon deposits. By choosing one of the cycles as the target interval, the changes of primary productivity parameters such as Ba, Ni, Cu and Zn and TOC content were studied based on the results of the TOC, S isotopes, DOP and trace elements of organic carbon in the form of pyrite and geochemical parameters The change of the organic matter accumulation and accumulation is mainly controlled by the primary productivity of the ocean surface and the redox conditions of the bottom water are related to the primary productivity.The accumulation of organic matter is finally attributed to the change of high frequency relative sea level and the rapid increase of sea level brings about abundant nutrients, Increasing the biological productivity of the marine surface layer, the decomposition of the marine organic matter consumes a large amount of oxygen and the oxygen demand increases to form an oxygen-deficient-anoxic environment in the bottom water.