Palynostratigraphy of the Macharetí and Mandiyutí groups (Carboniferous), northern Argentina and southern Bolivia: Part 1: stratigraphy, biostratigraphy and palynomorph rework

Abstract

The recognition of 165 indigenous species and their stratigraphic range in the Macharetí and Mandiyutí Groups from Tarija Basin (northern Argentina and southern Bolivia) allowed the proposal of a biostratigraphic scheme composed of a Superzone Kraeuselisporites volkheimeri-Circumplicatipollis plicatus (VP), which was divided into five First Appearance Interval Palynozones. The first three oldest zones, called Crassispora kosankei - Cystoptychus azcuyi (KA), Raistrickia radiosa - Apiculatasporites spinulistratus (RS), and Dictyotriletes bireticulatus - Cristatisporites chacoparanensis (BC), attributed to the Serpukhovian?-Moscovian, while the other two ones, Converrucosisporites micronodosus - Reticulatisporites reticulatus (MR) and Marsupipollenites triradiatus - Lundbladispora braziliensis (TB), were akin to the Moscovian-? Gzhelian. The age was based on the biostratigraphic range of several key species, the stratigraphic position, and the time involved in depositing the succession. The abundant presence of common species with other palynofloras from the Pennsylvanian of South America, especially from Argentina, also supports this age. Most of the 154 reworked species recognized are illustrated, confirming the deposition of Devonian strata that uplifted at the D-C boundary (Chanic Orogeny), developing the western Oriental Protocordilleran and south-eastern Michicola Arc. Both ranges were the boundaries of the southern part of the basin. They were eroded mostly during the Pennsylvanian. The Mississippian species also reworked into the Pennsylvanian assemblages, are evidence of deposition during this time in this region.