Análisis palinofacial de la Formación Lajas (Jurásico Medio), Cuenca Neuquina, Argentina. Significado paleoambiental y paleoclimático

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

REVISTA ESPANOLA DE MICROPALEONTOLOGIA

Instituto Geológico y Minero de España

Lugar: Madrid; Año: 2002 p. 81 - 104

0556-655X

Palynofacies analysis of outcrops samples of the Lajas Formation (Middle Jurassic) allowed to determinate a nearshore environment, well oxigenated and of high energy (tide and wave action) proximal to the sediment (continental) influx for this formation. These characteristics are similar to those determinated by lithofacial analysis in a sequence stratigraphic context. From the relative frequencies fluctuations of the vegetal families warm and humid conditions with a relative deterioration (template and sub-humic conditions) are inferred. These pulses corresponds to the Early Bajocian (JC4.2-TST until JC4.4-TST, with a maximum deterioration in JC4.3-TST) and in the Bathonian ? Callovian limit (JC5-TST). The cuali/cuantitative studies of the palynological organic matter (with transmitted light microscopy) and the thermal alteration index (TAI) allowed to determinate a scarce oleogenetic potential for all the formation (kerogen type III), with better perspective for the samples from deltaic systems.