The Permian palynological Lueckisporites-Weylandites Biozone in the San Rafael Block and its correlation in Western Gondwana

Abstract

A palynological study of the Yacimiento Los Reyunos Formation (San Rafael Block) Argentina was carried out in order to correlate the palynological data with other Permian assemblages and biozones from South America. The unit is included in the Cochicó Group deposited under the volcanic influence of the Choiyoi event. The palynological assemblages recovered from subsurface samples show a dominance of taeniate bisaccates like Corisaccites, Lueckisporites, Lunatisporites, Protohaploxypinus, Vittatina and Weylandites. A Lueckisporites complex, which would have biostratigraphical value, is established to include species of Lueckisporites, Corisaccites and Staurosaccites showing a wide morphological variation. The composition of the assemblages allows their inclusion in the Lueckisporites/Weylandites Biozone of Argentina, which is closely related to other biozones from southern South America. Analysis of the distribution of the species using cluster analysis confirms its similarity with the biozones from Bolivia and Brazil. Radiometric datings suggest an age not older than Kungurian for the occurrence of these assemblages in the Southern Hemisphere.