A detailed Lower Triassic conodont biostratigraphy and its implications for the GSSP candidate of the Induan–Olenekian boundary in Chaohu, Anhui Province

Chaohu is located in a deep part of carbonate ramp on the Lower Yangtze Block, which belonged to the low-latitude eastern Tethyan archipelago during the Early Triassic. Fossils were very rich in the Lower Triassic of Chaohu. Bivalves, ammonoids, conodonts were very common throughout the Lower Triassic, while fish fossils were generally rich in some beds of the upper part. It is one of the most typical sections for the Early Triassic chronostratigraphy in the world. Although various fossils had been studied in the 1980s and 1990s, recent studies based upon new and more detailed collections from the Lower Triassic of Chaohu showed that the conodont zonation needs revision. We collected Lower Triassic conodont fossils from continuous sections of the West Pingdingshan, North Pingdingshan and South Majiashan, Chaohu, Anhui Province, and updated zonations were made for each section. Eight conodont zones have been distinguished. They are, in ascending order, Hindeodus typicalis zone, Neogondolella krystyni zone, Neospathodus kummeli zone, Neospathodus dieneri zone, Neospathodus waageni zone, Neospathodus pingdingshanensis zone, Neospathodus homeri zone, and Neospathodus anhuinensis zone. The first occurrence of Neospathodus waageni eowaageni of the N. w. eowaageni subzone （i.e. the base of the N. waageni zone） is suggested as the marker to define the Induan-Olenekian boundary.     

中国三叠纪含牙形刺地层

十年来,中国三叠纪牙形刺地层的研究取得了很大的成绩。1.三叠纪含牙形刺地层主要分布在中国南方,尤其在昆仑-秦岭一线以南,此地层发育程度由西向东逐渐减弱,例如:西部珠峰地区分布在整个三叠系地层中,向东到下扬子地区,主要分布在下三叠统中。2.中国三叠纪牙形刺很丰富,已发现39属,230种,可划分成24个带。3.在奥伦尼阶,我国牙形刺根据生态可划分为两种类型:(1)盆地型(珠峰类型),(2)台地型(湖北利川类型)。     

黔西南三叠系永宁镇组牙形石研究—兼论下,中三叠统界线

本文首次系统描述了贵州贞丰县龙场、关岭县永宁镇的永宁镇组牙形石5属12种;在永宁镇组中识别出4个牙形石组合带(层)(由下而上):1. Pachycladina obliqua-Parachirognathus delicatulus带,2. Neospathodus homeri-Neospathodus triangularis.带,3. Neogondolella cf. jubata-Neospathodus timorensis带,4. Neogondolella navicula navicula-Neogondolella constricta层;首次将下、中三叠统的界线置于 Neogondolella navicula navicula-Neogondolella constricta层之底,即永宁镇组第4段之底。两统之间为整合接触。     

四川盆地二叠系牙形石研究及其油气意义

二叠系以海相碳酸盐岩地层为主,是四川盆地的重要产气层之一。作者对33条剖面进行了系统的工作,在取得丰富牙形石资料的基础上,对该区二叠系的地层划分与对比,二叠系至三叠系底部的Neogondolella和Anchignathodus属的演化系列,沉积相与牙形石的关系,和根据上二叠统牙形石色变判断上三叠统油气成熟度指标等进行研究     

江西信丰县铁石口地区二叠—三叠纪牙形石动物群的发现及其地质意义

本文首次报道并描述了江西信丰县铁石口地区的二叠—三叠纪的牙形石动物群;根据牙形石和菊石、双壳类、腕足类,将“铁石口系”划分为三部分:下部(层1～10)、中部(层11～20)、上部(层21～23),它们分别相当于Griesbachian阶、Nammalian阶、Spathian阶。层2～8中发现了二叠纪型和三叠纪化石伴生的混生动物群。三叠系与二叠系之间可暂时以层1厚约3cm的黄白色粘土岩为界线,二系为整合关系。