The Holmograptus lentus Zone (Middle Ordovician) in the La Invernada Range, Precordillera of San Juan, Argentina

BANCHIG, A.L.; ALBANESI G.L; ORTEGA G.; VOLDMAN, G.G.

Novosibirsk

Congreso; 13º International Symposium on the Ordovician System; 2019

TROFIMUK INSTITUTE OF PETROLEUM GEOLOGY AND GEOPHYSICS RUSSIAN ACADEMY OF SCIENCES SIBERIAN BRANCH NOVOSIBIRSK NATIONAL RESEARCH STATE UNIVERSITY

Darriwilian graptolite faunas are widely distributed in the Central and Eastern Precordillera, western Argentina, preserved in diverse lithofacies in the Gualcamayo, Los Azules, Las Aguaditas and Sierra de La Invernada formations.The Holmograptus lentus Zone (middle Darriwilian) has been recognized in diverse localities of the Central Precordillera, placed above strata bearing graptolites of the L. dentatus Zone. The discovery of middle Darriwilian graptolites of the Holmograptus lentus Zone in calcarenites near the Estancia Don Carmelo hostel, on the western flank of the La Invernada Range is reported in the present work. The fossiliferous samples were taken few meters to the east of the hostel in a succession of sandstones, calcarenites, and shales corresponding to the middle part of the Sierra de La Invernada Formation.