New palynological record for the Puesto Albornoz Formation (Golfo San Jorge basin, Argentina): Stratigraphic and paleoenvironmental implications

Abstract

Palynomorph assemblages were recovered from the Puesto Albornoz Formation (Golfo San Jorge Basin, Southern Argentina) at its type locality. The scarcity of outcrops with a continental Lower Cretaceous sedimentary record in this basin, and its marginal position in the western sector of the studied area, make Puesto Albornoz a unique and key locality for determining the timing of the basin evolution during the Cretaceous. The palynological content includes thirty-five spore species, twenty-one pollen taxa, and two algae. Among the fifty-eight species identified, forty-eight were identified for the first time for the unit. Based on the previous records of the analyzed taxa, a late Valanginian to Barremian, and more probably late Valanginian to Hauterivian age is inferred for the studied palynoflora. The palynological assemblages studied here closely resemble the Interulobites-Foraminisporis Zone (late Valangian-Hauterivian) of the Argentinian Patagonia, and the Cyclusphaera psilata-Classopollis association (late Valanginian-Barremian) of the Neuqu´en Basin.