安徽巢北地区栖霞组臭灰岩段富有机质成因探讨

以安徽巢北地区二叠纪栖霞组臭灰岩段为研究对象，从岩石学、古生物学及沉积学特征出发，探讨臭灰岩段富有机质与风暴事件沉积之间的关系。臭灰岩段岩性整体为灰黑色中厚层状石灰岩，层间夹数毫米至数厘米厚灰黑色钙质泥岩，整套岩层富含有机质；其中生物化石丰富，整体为热带、亚热带正常盐度浅水生物组合为特征；为正常浅海碳酸盐岩台地沉积，沉积期表现为一个明显的海侵过程，并受风暴作用的频繁扰动。臭灰岩段沉积环境并非“贫氧或缺氧”条件，而是正常富氧环境。富有机质特征一方面得益于沉积期较高的生物产率，同时还与风暴事件沉积作用密切相关，即在风暴作用下，沉积物发生快速堆积，有机质未来得及与富氧水体发生长期接触即被埋藏覆盖，从而导致有机质被良好保存，形成臭灰岩段富有机质特征。风暴作用频发与研究区臭灰岩段沉积期所处的低纬度特征有关。

Interpretation of Rich Organic Matter in Swine Limestone Member of the Permian Chihsia Formation, Chaobei, Anhui

Research Swine Limestone Member of the Permian Chihsia (Qixia) Formation in Chaobei, Anhui, aimed at discussing the relationship between rich organic deposits and Tempestite Sediments. Swine Limestone Member is generally composed of limestone (grey black, medium bedded) and a small amount of calcareous mud stones (grey black, few millimeters or centimeters thick) which are sandwiched between above limestone layers. This set of strata contains a lot of fossil remains which reflect tropical or subtropical zone, normal salinity, natural shallow sea environment. According to the petrologic, palaeontological and sedimentological features, the study indicates that Swine Limestone Member generally deposits in normal shallow sea carbonate platform, the water in which is not dysoxic or anoxic. Based on the large biomass liveweight, the rich organic feature of Swine Limestone Member would profit from more rapid and large deposits by frequent storms. In rapid deposition conditions, organic matter could not be oxidized before being buried rapidly. Frequent storms due to the relatively low palaeolatitude in the deposition period.