中国科学院南京地质古生物研究所机构知识库

We report conodont assemblages from the Dardong Formation of the Xainza area, Lhasa Block, yielding several chronostratigraphically significant conodont elements discovered from the Lhasa Block for the first time, including Gondwania profunda, Polygnathus pannonicus, P. kitabicus, P. cf. sokolovi and P. excavatus excavatus. Two conodont zones are identified, namely, the middle Pragian profunda Zone and the lower Emsian excavatus Zone. The Pragian-Emsian boundary is presumably located within the interval between bioclastic limestone beds 4 and 6 with an interbed of siltstones. Although the sparse conodont occurrences in this study precludes more precise chronostratigraphic subdivision, the Xainza area of the Lhasa Block is potentially important for recognition of Lower Devonian stage boundaries in China and deserves further conodont investigations. (c) 2023 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights are reserved, including those for text and data mining, AI training, and similar technologies.