以下扬子巢湖地区茨苔山二叠系栖霞组碳酸盐地层为研究对象,开展元素地球化学检测,探讨古生产力和保存条件与烃源岩发育间的关系。结果表明:Ba、TN对生物有机质作用响应明显,可作为栖霞组灰岩地层古生产力的替代指标,V/(V+Ni)缺氧指标适用于栖霞组灰岩地层,指示栖霞组整体缺氧的沉积特征,两类参数均显示相对海平面升降变化对沉积水体生产力水平和缺氧程度有控制作用;栖霞组碳酸盐烃源岩的形成是低等藻类生产力水平以及保存条件(缺氧的沉积环境)良好匹配的结果,在生产力水平和缺氧程度整体最高的本部灰岩下段地层中烃源岩最发育。
The Lower Permian carbonate deposits of the Chihsia Formation located in Chaohu, Lower Yan- gtze are studied in this paper, with emphasis on the relationship between paleoproduetivity, redox condi- tions and the formation of source rock, upon the basis of element geochemistry. The results demonstrate that Ba and TN have evident relations with biological deposition and can be used as a geochemical proxy for paleoproductivity. V/(V2c-Ni)ratio, as a geochemical proxy to reconstruct the paleoredox, indicates that the Chihsia Formation was formed in an oxygen-deficient environment. The above mentioned proxies sug- gest that paleoproductivity and paleoredox have close relation with sea level fluctuation. The effective matching of algae productivity and preservation condition made the region favorable for source rock forma- tion while the Chihsia Formation was deposited. High quality source rocks mainly occur in the lower part of the Middle Limestone Member of the Formation.