巴基斯坦盐岭地区二叠纪生物地层研究的新进展

近30年来，巴基斯坦盐岭地区的Wargal组和Chhidru组以及在喜马拉雅地区相当地层的地质时代被许多学者视为中二叠世(瓜达鲁普世)。根据华南与盐岭地区瓜达鲁普统和乐平统的牙形类化石带对比，可以确定Amb组和Wargal组底部的时代为瓜达鲁普世晚期，瓜达鲁普统与乐平统的界线位于Wargal组下部，吴家坪阶与长兴阶的界线位于Chhidru组的下部，而二叠与三叠系的界线位于Mianwali组下部的Kathwai段之内。我国西藏南部色龙群及相当地层含有与巴基斯坦盐岭地区Kalabagh段和Chhidru组可对比的乐平世腕足动物群以及二叠系—三叠系界线附近连续的牙形类化石带，由此可以推定色龙群的时代应为乐平世。

LATEST BIOSTRATIGRAPHICAL ADVANCES OF THE PERMIAN SYSTEM IN THE SALT RANGE, PAKISTAN

During last three decades, the Wargal and Chhidru Formations in the Salt Range, Pakistan and their equivalents in the Himalayan region have been considered by many authors to be Middle Permian (Guadalupian) in age. Based on the correlation of the Guadalupian and Lopingian conodont zones of the Salt Range, Pakistan with those of South China, the Amb Formation and the lower part of the Wargal Formation in the Salt Range, Pakistan are Late Guadalupian in age. The Guadalupian/Lopingian boundary is in the lower part of the Wargal Formation, and the Wuchiapingian/Changhsingian boundary is in the lower part of the Chhidru Formation. The Permian/Triassic boundary is in the Kathwai Member of the Mianwali Formation. Thus, it can be inferred that the Selong Group in the southern Tibet is also Lopingian in age in view of its correlatable brachiopod faunas with those of the Kalabagh Member of the upper Wargal Formation and the Chhidru Formation and the conodont zones around the Permian/Triassic boundary in southern Tibet.