论文部分内容阅读
国际上寒武纪的开始以遗迹化石Treptichnus pedum的首次出现为标志,我国南方通常以小壳化石的出现或者疑源类Asteridium-Comasphaeridium-Heliosphaeridium化石组合的出现作为前寒武纪-寒武纪界线。由于化石保存的不完整性,仅仅依靠寒武纪化石的首现来确定埃迪卡拉纪-寒武纪界线可能导致其层位偏高,因此需要利用界线之下的埃迪卡拉纪化石对界线进行进一步限定。皖南地区的埃迪卡拉纪-寒武纪界线一直被厘定在皮园村组硅质岩和荷塘组底部磷块岩或黑色页岩交界处,这一划分主要是根据岩石地层的证据和邻区的生物地层资料,但是皮园村组本身缺乏直接的生物地层学资料。为了进一步确定皖南地区的埃迪卡拉纪-寒武纪界线和皮园村组的沉积年龄,系统研究了皖南休宁蓝田剖面皮园村组中的微体化石组合,在皮园村组中发现了埃迪卡拉纪化石Horodyskiacf.minor、Palaeopascichnus cf.jiumenensis、Palaeopascichnus sp.,以及未定名的纺锤状化石和球形化石。Palaeopascichnus在全球范围的埃迪卡拉纪地层中都有发现,且其仅仅局限在埃迪卡拉纪的晚期。在华北地台西缘的正目观组板岩和华南留茶坡组硅质岩曾报道有Horodyskia minor,H.moniliformis?(有可能为H.minor的同物异名),Palaeopascichnus minimus,P.meniscatus,和P.jiumenensis。在皖南Palaeopascichnus cf.jiumenensis和Palaeopascichnus sp.出现在皮园村组硅质岩的中上部,Horodyskiacf.minor一直延伸到皮园村组的顶部,说明由生物地层所划分的埃迪卡拉纪-寒武纪界线与皮园村组-荷塘组岩石地层的界线基本上是一致的。
The beginning of the international Cambrian is marked by the first appearance of the relic fossil Treptichnus pedum. In southern China, the occurrence of small shell fossils or the combination of Asteridium-Comasphaeridium-Heliosphaeridium fossils are usually used as the Precambrian-Cambrian boundary . Due to the incompleteness of the fossil deposits, it is only necessary to rely on the first occurrence of the Cambrian fossils to determine that the Edicar-Cambrian boundary may lead to its high horizon. Therefore, Further restrictions apply. The Edicala-Cambrian boundary in southern Anhui has been determined at the junction of the Pianyuan Formation siliceous rock and the bottom of the Hetang Formation with phosphate rock or black shale. This division is mainly based on evidence from rock formations and adjacent areas However, the Piyuan Village Group itself lacks direct bio-stratigraphic data. In order to further determine the sedimentary age of the Edicarcao-Cambrian boundary line and the Piyuancun Formation in Southern Anhui Province, microfacies assemblages in the Piyuancun Formation in the Lantian section of Xiuning, Southern Anhui Province were systematically studied and found in the Piyuancun Formation The Ediacaran fossils Horodyskiacf. Minor, Palaeopascichnus cf.jiumenensis, Palaeopascichnus sp., As well as the unspecified spindle-shaped fossils and spherical fossils. Palaeopascichnus is found in the Edith Calanichi stratigraphy worldwide, and it is confined to the late Edith Karachi. Horodyskia minor, H. moniliformis? (Homologs of H. minor possibly), Palaeopascichnus minimus, P .meniscatus, and P.jiumenensis. The Palaeopascichnus cf.jiumenensis and Palaeopascichnus sp. Occur in the middle and upper part of the Permian group of siliceous rocks in southern Anhui. The Horodyskiac f. Minor extends to the top of the Piyuan village, indicating that the Edilocian-Cambrian The boundaries between the Jiri line and the Piyuan village-Hetang formation are basically the same.