Asociaciones palinológicas en las formaciones Los Monos (Devónico) e Itacua (Carbonífero Inferior) en Balapuca (cuenca Tarija), sur de Bolivia. Parte 1. Formación Los Monos

DI PASQUO, MARÍA DE LAS MERCEDES

REVISTA GEOLOGICA DE CHILE

Servicio Nacional de Geología y Minería

Lugar: Santiago; Año: 2007 vol. 34 p. 97 - 137

Palynological assemblages present in Los Monos (Devonian) and Itacua (Lower Carboniferous) formations at Balapuca (Tarija basin), southern Bolivia. Part One. Geology, stratigraphy and Los Monos formation assemblages. Two associations of palynomorphs recovered from eight samples from Los Monos Formation (late Eifelian-early Frasnian), cropping out at Balapuca, located at the Bolivian margin of the Bermejo River in the San Telmo range, are characterized. In the Tarija Basin, this unit overlies the Pescado (or Huamampampa) Formation (Emsian-Eifelian) and underlies the Iquiri Formation (Frasnian-Famennian), when it is preserved. The studied section is mainly composed of grey laminated or massive pelites and sandstones with current structures or bioturbation. Paleoinvertebrates and plant debris were recovered from different levels, and some of them yielded palynomorphs. The whole microflora here presented, is composed of 76 species, of which trilete spores are dominant and  acritarchs, prasinophytes, cryptospores and chitinozoans are present subordinately. Two new species of spores, Leiotriletes balapucensis y Endoculeospora altobellii, both belonging to the youngest assemblage, are described. Two assemblages are recognized based on the stratigraphical distribution of diagnostic species, one attributed to the late Eifelian and the late early Givetian to the late Givetian. Both associations share several species with other coeval microfloras mainly from Argentina, Bolivia, Brazil, and beyond South America, from North America and western Europe.