Gzhelian-early Cisuralian palynofloras from the Panacán Formation, Precordillera de San Juan, Argentina

Abstract

Recent decades have seen significant advancements in our understanding of the palynological aspects of the Carboniferous–Permian boundary in Gondwana. Postglacial successions of western Gondwana are characterized by a dominance of taeniate and sulcate pollen, primarily represented by genera such as Illinites, Marsupipollenites, Pakhapites, Protohaploxypinus, and Vittatina. Additionally, spores are represented by a limited number of taxa, including the key species Converrucosisporites confluens Morphon. These palynofloras are indicative of the Pakhapites fusus-Vittatina subsaccata Biozone (Gzhelian–early Cisuralian) defined for central-western Argentina. This study describes a new record of this biozone from Puesto Trapiche (San Juan province), one of the earliest known fossiliferous sites dating back to the 1890s. Two samples collected from the upper facies association of shales, mudstones, and fine-grained sandstones of the Panacan ´ Formation, representing a brief transgressive event, were productive for the first time. The diverse composition of the assemblages allowed for the identification of over sixty species, enabling a closer correlation with other stratigraphic units in Argentina and other areas of Gondwana.