Early Permian Conodonts from the Baoshan Block, Western Yunnan, China

Abstract

The Rabeignathus bucaramangus fauna was recently found from the limestone beds of the top part of the clastics‐dominated Dingjiazhai Formation in the Aluotian section, southern Baoshan Block, western Yunnan. With Rabeignathus bucaramangus as the dominant species, this fauna includes Rabeignathus bucaramangus (Rabe), Homeoiranognathus huecoensis (Ritter), Sweetognathus inornatus Ritter, Sweetognathus whitei (Rhodes), Mesogondolella cf. bisselli (Clark and Behnken) and a few of ramiform elements. The characteristics of the fauna suggest that it can be correlated with the upper part of the Sweetognathus whitei Zone and assigned to the Middle Artinskian.

A late Cisuralian (early Permian) brachiopod fauna from the Taungnyo Group in the Zwekabin Range, eastern Myanmar and its biostratigraphic, paleobiogeographic, and tectonic implications

“…It has been widely recognized that the Cisuralian deposits of the Sibumasu Block are characterized by glacial-marine diamictites containing typical cold-water biotas (Shi and Archbold, 1995;Metcalfe, 2002Metcalfe, , 2011Ueno and Charoentitirat, 2011;Ridd, 2016). Above the glacial-marine diamictites, marine faunas and their paleobiogeographic affinities progressively changed in the Permian during the northward drifting of the Cimmerian continents (Shi and Archbold, 1998;Jin, 2002;Ji et al, 2004;Shi et al, 2011;Shen et al, 2013;Zhang et al, 2013Zhang et al, , 2014Ueno et al, 2015;Yuan et al, 2016;Xu et al, 2019), as well as paleoclimatic amelioration from an icehouse to a greenhouse regime (Chen et al, 2013;Zhang et al, 2013;Haig et al, 2017;Liu et al, 2017). Thus, it can be assumed that the faunas and sedimentary sequences are different if the Irrawaddy Block and Sibuma Block had different tectonic and paleogeographic evolutionary histories.…”