Assignment of Izúcar de Matamoros evaporites to Cuayuca Formation and its correlation with other Mexican Cenozoic formations based on parsimony analysis of endemicity (PAE) methodology.

RAMIREZ-ARRIAGA, E.; MARTINEZ-HERNANDEZ, E.; FLORES OLVERA, H.; OCHOTORENA, H.; PRAMPARO, M. B.

PALYNOLOGY

AASP

Lugar: Dallas, Texas, U.S.A.; Año: 2008 vol. 32 p. 231 - 252

0191-6122

ABSTRACT Based on Izucar de Matamoros (IzM) section’s lithology and the occurrence of index taxa such as Armeria, Corsinipollenites, Cicatricosisporites dorogensis, Eucommia, Momipites coryloides, Momipites tenuipolus, Mutisiapollis and Ranuculacidites operculatus a palynostratigraphic correlation between IzM and Cuayuca Formation stratotypes is proposed. The results obtained indicated that the IzM sections are late Eocene–early Oligocene and they would be part of the evaporitic member (Mcy) of the Cuayuca Formation. The new data reinforce the paleoenvironmental interpretations proposed for the formation, which was probably deposited under local xeric conditions in a semiarid climate, that allowed the development of grassland (Gramineae with Amaranthaceae-Chenopodiaceae and Ephedra) and thorn shrub community with Acacia, other Leguminosae, Linum and Plumbaginaceae. The neighboring communities were probably tropical deciduous forests, low tropical deciduous forest, thorn forest and chaparral. Finally, there were regional temperate vegetations such as a Pinus and Picea forest, as well as a cloud forest community. Using the parsimony analysis of endemicity (PAE) a biogeographic method, a palynofloristic relationship between the Cuayuca Formation and Pie de Vaca Formation (late Eocene–early Oligocene) is proposed. Both formations are part of the Balsas group and are correlated with San Gregorio Formation (Oligocene) of Baja California Sur.