PALINOLOGIA DEL PALEOZOICO SUPERIOR DE LA PERFORACION LAS MOCHAS, PROVINCIA DE SANTA FE, ARGENTINA

CESARI, S.N.; ARCHANGELSKY, S.; VILLAR DE SEOANE L.

AMEGHINIANA

ASOCIACION PALEONTOLOGICA ARGENTINA

Año: 1995

0002-7014

taxonomicand biostratigraphic study of palynologicalassemblages found in thc wellSH-Las Mochas x-1 is presented. This well is locatedin Santa Fe province wherc the Clhacoparanense basin. comprising a thick Late Paleozoic sequence was developed. Eighty onespecies have been identified, some being new: Gnndisporifes serrrt Iatrrs, L~rndbladisporaa rec~lata.P rotohaploxypirtuspaucitaeniatus. Sclteuringipolleni~es circrtlaris and Cycadopites ailruampai. Brevitrifetes irreglrlaris (Nahuys, Alpern etYkrt), Dia~ontozonotrilefess~ tbbncrtiifer~(tNs ahuys, Alpem et Ybert), Hnrriditrileres srtperbrrs (Faster), and Dis~rinn~nnosaccitescrucisrriatus (Ybrt), are new combinations. Twenty one species are mentioned for the first time in this basin, althoughsome are known to occur in the neighbouring Brazilian Parani Basin. The distribution of the most important species along thesection shows a significant compositional change at the top of the sequence that is considered ro be an iniportant zone boundary.It may be equivalenl to a similar change that was previously recorded in this basin by several authors. Contrasting spore-pollengroup percentages are alsoconsistent with this interpretation. The thickest part of this succession is cotrelared with the knownCristutisporites Zone (Early Permian) while the basal strata are probably representing the Polonieisporilcs-LitndbladisporaZone (Late Carboniferous). Although it is possible to recognize a subdivision of the Crisrufisporites Zone into three subunits,as suggested recently by Vergel (1993). there is no coincidence with taxa used by this autlior to define those subunits becausemost are lacking in L s Mochas well. However. there are some taxa with coincident ranges that suggest a threefold subdivisionof thiszone. It is concluded that different plant communities may have been present reflecting variable ecological conditions.These conditions may well have been responsible for the differences in composition of thc observed subunits in the Crisr~fispnriteZs one.