Palynology of the Lower Permian in the CLS-24 borehole (Cerro Largo Sur), Cerro Largo Department, Uruguay. Part II: Pollen grains

摘要

The systematic description of pollen grains from four sidewell cores of Cerro Largo Sur-24 borehole (14.9, 14.8, 7.8, and 3.5 mbs), referred to the upper part of the San Gregorio Formation (Melo, Cerro Largo Department, Uruguay) is presented. The assemblages are represented by spores, prasinophytes, and acritarchs (described in Part I), and pollen grains. The pollen species comprise monosaccate, bisaccate, striate, and colpate grains. The assemblages are datable as Early Permian based on previous records of selected miospore taxa, and are partially correlated to the Cristatisporites Biozone (Chacoparanense Basin), the Pakhapites fusus-Vittatina subsaccata Biozone (Paganzo, Calingasta-Uspallata, Rio Blanco, and San Rafael basins), and the Vittatina costabilis Biozone (Parana Basin). The mudstones yielding the palynomorphs belong to the upper part of the San Gregorio Formation and would correlate with the post-glacial transgression recorded in Brazil (Itarare Group) and Argentina (Sachayoj-Charata and Orddnez-Victoriano Rodriguez formations).