Biofacies y estratigrafía del Liásico de Piedra Pintada, Neuquén, Argentina

DAMBORENEA, S.E.; MANCEÑIDO. M.O.; RICCARDI, A.C.

Tucumán

Congreso; 1° Congreso Argentino de Paleontología y Bioestratigrafía; 1974

Asociación Paleontológica Argentina

Data of 96 genera, mostly of invertebrates, in 44 samples collected from 5 stratigraphic sections were examined using the Jaccard Coefficient for, data comparison and the UPGMA for clustering coefficients. The same analysis was also performed using only the 50 bivalve genera recorded in the same samples. The results for the Q-mode do not reproduce, as could be expected, the order of samples in the sections, implying therefore that their composition is more dependent on facies and life conditions than On age differences. The groups and subgroups displayed at the 0,030 and 0,135 levels are in agreement with the dendrograms for the R-mode of the same data. Therefore it has been possible to recognize and characterize 2 main biofacies which are correlated with different lithologies and 7 sub-biofacies with distinctive relationships among the mobility-trophic-substrate groups. The stratigraphic and geological implications of the results are consistent with other data and can be used to postulate a new scheme for the geology of the area. The Jaccard. Coefficient and the UPGMA have been also used to establish the similarities among taphofloras from regionally related lithostratigraphic units with several taphofloras from other Triassic and Jurassic localities of Argentina.