CONODONTS FROM THE SANTA ROSITA FORMATION (PALTODUS DELTIFER ZONE, EARLy ORDOVICIAN) IN THE SANTA VICTORIA AREA, CORDILLERA ORIENTAL, NW ARGENTINA

G. G. VOLDMAN; G. L. ALBANESI; C. R. MONALDI; F. J. ZEBALLO

Mendoza

Simposio; 3rd International Conodont Symposium & Regional Field Meeting IGCP 591; 2013

The Cambrian - Lower Ordovician stratigraphic units from the Cordillera Oriental were traditionally assigned to the Santa Victoria Group,one of the classical lower Paleozoic units of northwestern Argentina. is group encompasses the Santa Rosita Formation and the Acoite Formation,originally defined in the Santa Victoria Range, Salta Province, NW Argentina. We describe the first conodont records from the Santa RositaFormation at its type area, in a preliminary approach to reconstruct the complex stratigraphy of the Santa Victoria Range. A series of 15conodont samples, each weighting 2-3 kg, from the Santa Rosita Formation were collected from sections at the southern margin of the SantaVictoria River, near the homonymous locality, as well as from the Peña Blanca Creek, on the path that connects Santa Victoria with Mesón,and from the San Felipe Creek, along the way to Acoite locality. Only 5 of the total number of samples were productive, yielding over 4500conodont elements. Complete apparatuses and diagnostic elements of Paltodus deltifer deltifer (Lindström) were recovered from the Peña Blancaand San Felipe sections in Santa Victoria, along with Acanthodus humachensis Zeballo and Albanesi, Acodus primitivus Zeballo and Albanesi,Decoriconus peselephantis (Lindström), Drepanodus arcuatus Pander, Drepanoistodus chucaleznensis Albanesi and Aceñolaza, Kallidontus gondwanicusZeballo and Albanesi, Paltodus deltifer peracutus (Lindström), Paroistodus numarcuatus (Lindström), Utahconus purmamarcensis Zeballo and Albanesi,U. scandodiformis Zeballo and Albanesi, Variabiloconus variabilis (Lindström) and the long-ranging paraconodonts Phakelodus elongatus (Zhang)and Ph. tenuis (Müller). Two new species of Drepanoistodus and Filodontus were recognized. Collected specimens exhibit a CAI 3 and correspondto the Paltodus deltifer deltifer Subzone of the P. deltifer Zone (middle Tremadocian, Tr2). e studied assemblages include conodont speciesof wide intercontinental distribution as well as endemic forms from the Central Andean Basin, which characterize a faunal province with a particularsignature from the Shallow Water Realm.