Una fauna de braquiópodos arenigianos (Ordovícico temprano) en rocas volcanoclásticas de la Puna occidental de Argentina: implicaciones paleoclimáticas y paleogeográficas

Abstract

A fairly well-preserved and rich brachiopod fauna is described for the first time from the Puna region of northwestern Argentina. The Arenig volcaniclastic rocks cropping out at Vega Pinato contain two new genera and species, the clitambonitid Pinatotoechia acantha and the clarkellid Punasirophia multiseptaia. Associated brachiopods are Hesperonomia sp., Finkelnburgia sp., Oligorthis? sp., Tritoechia sp. A, Tritoechia sp. B, Jaanussonites? sp., Imbricatia sp., Rugostrophia sp., and three undetermined genera belonging to the Orthoidea, Enteletoidea and Porambonitidae. The presence of several pentamerids and clitambonitoideans is unusual in coeval assemblages of northwestern Argentina. The Vega Pinato association compares most closely with the Arenig faunas of the Famatina and the Precordillera basins, which are usually considered as laying at intermediate to low paleolatitude, respectively.