201. New fusulinid assemblages from the Changning-Menglian Belt in western Yunnan, China and their paleogeographic implications.
- Author
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Huang, Hao, Jin, Xiaochi, Shi, Yukun, Zheng, Jianbin, and Yan, Zhen
- Subjects
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PALEOGEOGRAPHY , *CORAL reefs & islands , *LIMESTONE , *OCEAN , *CARBONATES , *SOCIAL dominance ,GONDWANA (Continent) - Abstract
[Display omitted] • Constraints from fusulinids for the paleogeography of Changning-Menglian Belt, China. • New collections of late Carboniferous to Early Permian fusulinids from two sections. • Similar but less diverse by statistical comparison (Rarefaction) with South China. • Seamount atoll between peri -Gondwana and Cathaysia plausible for these carbonates. The Changning-Menglian Belt in western Yunnan, China, is a critical tectonic zone that preserves remnants of the Paleotethys Ocean, including limestones of possible seamount origin. Fusulinids, sensitive indices for age and paleoenvironment, are abundant in these limestones but have rarely been the subject of taxonomic study. This paper presents new fusulinid collections of middle Kasimovian (Late Carboniferous) to Artinskian (Early Permian) age from two sections located in the middle and northern parts of this belt. In the Mangyang Section, the fusulinids are grouped into the Triticites abundance zone and the Sphaeroschwagerina sphaerica range zone, while in the Anxincao Section, they comprise the S. sphaerica range zone, the Eoparafusulina interval zone and the Chalaroschwagerina solita range zone. The distinct Cathaysian affinity is indicated by the dominance of Triticites in the Late Carboniferous and Early Permian assemblages characterized by Sphaeroschwagerina, Eoparafusulina and Chalaroschwagerina. On the other hand, these fusulinids contrast sharply with coeval fusulinids in the peri -Gondwana region, which are impoverished and dominated by Eoparafusulina / Pseudofusulina. However, Early Permian fusulinids in this belt still differ from their counterparts in Cathaysian South China in terms of 1) lower diversity, as confirmed by a robust quantitative comparison (Rarefaction analysis); 2) peculiar rarity of Pseudoschwagerina. Collectively, these data imply that the studied fusulinids probably colonized marine environments far from the mid-latitude peri -Gondwana region, while detached from equatorial South China. This interpretation is consistent with the previous view that these limestones were formed on seamount atolls within the vast Paleotethys Ocean. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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