PALYNOLOGICAL ZONATION, PALEOENVIRONMENTAL

MARTÍNEZ, MARCELO A.; QUATTROCCHIO, MIRTA E.; ZAVALA, CARLOS A.

San Antonio, Texas

Otro; Thirty-Fourth Annual Meeting of the American Association of Stratigraphic Palynologists; 2001

American Association of Stratigraphic Palynologists

The Neuquén Basin is a back-arc basin, located in the western central part of Argentina. It originated during latest Triassic times and was an important region of sedimentation during the Jurassic and Early Cretaceous. The Cuyo Group (Lower-Middle Jurassic) represents the first major marine depositional episode after the formation of the basin. The study area is located in the southern part of the Neuquén Basin close to Zapala city (38° 48´?39° 16´ S and 70° 03´?70° 06´ W) and comprises four sections (Lohan Mahuida, Puente Picún Leufú, Puesto Bascuñán and Portada Covunco). In the Cuyo Group, the Lajas Formation consists of sand-rich shallow marine deposits (late Aalenian ? early Callovian). From the sequence stratigraphic and biostratigraphic studies (mainly ammonites) three third-order depositional sequences (JC4, JC5 and JC6) and five 4th order sequences (JC4.1 to JC4.5) has been recognized in this formation. The objective of the present study is to analyze the palynological organic matter (palynomorphs, phytoclasts and amorphous organic matter) of 37 outcrop samples belonging to the Lajas Formation.