扬子区晚震旦世动物化石新材料

NEW MATERIAL OF ANIMAL FOSSILS FROM THE UPPER SINIAN OF THE YANGTZE REGION, SOUTHERN CHINA

扬子区晚震旦世地层中已有多种类型的动物及遗迹化石的报道。文中补充了不同地区和层位的骨骼及遗迹化石新材料 ,包括 :江西上饶王家院陡山沱组顶部磷块岩中的磷酸盐化“十”字形骨针和云南晋宁王家湾灯影组上段隧石条带中的单轴双射硅质骨针 ,它们可能分属于钙质海绵和普通海绵类 ;贵州瓮安陡山沱组上段磷质白云岩中的可疑壳状化石 ;宜昌三斗坪金瓜墩陡山沱组下部 (第二段 )遗迹化石 ;瓮安陡山沱组上段及湖北南漳灯影组上段底部磷质硬底中的生物扰动构造。另外还报道了贵州清镇桃子冲剖面桃子冲组最底部的瓶状动物 (Pro tolagenalimbata)化石 ,并认定桃子冲组与灯影组之间为假整合接触 。

The animal and trace fossils from the Upper Sinian of the Yangtze region, referred to not a few of categories , have been recorded in some treatises. This paper adds new material of skeletal and trace fossils from various sections and horizons of the Upper Sinian of the Yangtze region. These are (1) a phosphatic crossed spicule from the phosphorite of the uppermost part of the Doushantuo Formation at Wangjiayuan, Shangrao, Jiangxi Province and a siliceous single axial spicule from the stripped chert intercalated in the Upper Member dolostones of the Dengying Formation at Wangjiawan, Jinning, Yunnan Province, which might be respectively referred to Calcarea and Demospongiae; (2) a problematic shelly fossil from the phosphoric dolostone of the Upper Member of the Doushantuo Formation in Weng'an, Guizhou Province; (3) trace fossils, just like Funisichnus grammatus Zhang et Dong from the Shibantan Member of the Dengying Formation, from the Second Member of the Doushantuo Formation at Jinguadun, Yichang, Hubei Province; (4) the bioturbatic structures of the phosphate hardgrounds from the Upper Member of the Doushantuo Formation of Weng'an and the base of the Upper Member of the Dengying Formation in Nanzhang, Hubei Province. In addition, a vase shaped fossil in the thin section, sampled from the lowermost part of the Taozichong Formation at Taozichong, Qingzhen, Guizhou Province, is first recorded in this paper. The horizon containing the vase shaped fossil was previously correlated with the uppermost horizon of the Sinian, actually it belongs to the lowermost Cambrian which overlies unconformably the Dengying Formation dolostones. The material reported here suggests that animals of different categories relatively throve in Late Sinian prior to the organism explosion in early Early Cambrian.