Early-Middle Darriwilian graptolite and conodont faunas from the Central Precordillera of San Juan Province, Argentina

FERNANDA SERRA; NICOLÁS A. FELTES; GLADYS ORTEGA; GUILLERMO L. ALBANESI

Simposio; 12th International Symposium on the Ordovician System; 2015

ABSTRACT: This study includes several localities from the Jáchal area in the Central Precordillera of San Juan Province: the Las Aguaditas Creek, Las Chacritas River, Oculta Creek, Potrerillo Hill and La Chilca Hill sections. We deal herein with the graptolite and conodont faunas recorded from units that overlie the carbonate San Juan Formation, spanning the lower part of the Las Aguaditas, Gualcamayo and Los Azules formations, and the Las Chacritas Formation in their respective areas. The index graptolites and associated species are reported, which enable the recognition of the L. austrodentatus and L. dentatus zones in the Central Precordillera. The Histiodella and Periodon lineages recognized in these units allow a tie with the graptolite zones, providing new information for global correlation purposes. The use of these zonations enhances the biostratigraphic resolution of the diachronic contact between the San Juan Formation and the overlying units.