【摘要】 黄茆D/C界线层自下而上的层序为:代化组顶部,属于Siphonodella praesulcata带;长顺页岩;王佑组,属于S.sulcata带和S.duplicata带。长顺页岩底部亲铁元素(铱等)和亲硫元素高度富集,此异常与K/Tr界线层陨石撞击引起的异常极为相似。该异常与牙形石综合资料,为D/C界线的选择提供重要依据。长顺页岩底界线代表重大事件(可能为陨石撞击)并伴随一些生物的全球性灭绝,而duplicata界线代表事件高峰后,牙形石和菊石开始分异的一条界线。更多还原

【Abstract】 The sequence of the section in ascending order is as follows. Uppermost Daihua Fm, it belongs to Siphonodella praesulcata Zone; Changshun Shale; Wangyou Fm, it belongs to S. sulcata Zone and 5. duplicata Zone.The Changshun Shale is distinctly enriched by siderophile elements Ir, Ni, Co, Cr, Fe, and sulphophile elements As, Sb, Se. The enrichment is about 20 to 100 times over background. This anomaly is similar to that of the Fish Clay of the Cretaceous/Tertiary boundary. The ratios of Au/Ni = 2.94 × 10-5, Co/Ni = 0.036, Cr/Ni = 0.23, they are similar to those of Cl-type chondrites.The evidence of conodonts and geochemical anomaly reveals that two boundaries for the D/C boundary are atractive. a. The base of the Changshun Shale represent a drastic event (caused presumably by meteorite impact) accompanied by the world-wide mass extinction, b. The base of duplicata Zone represents the starting point of the increase of diversity of conodonts and ammonoids following the event. The duplicata boundary coincides with the Gattendorfia boundary and can be defined well within continuous limestone in South China not only in the basinal facies, but also in some shallow-water facies.更多还原