Unraveling late Pennsylvanian brachiopod assemblages from the San Rafael Basin (Argentina): Biostratigraphic implications to southwestern Gondwana

TABOADA, A.C.; C.A, PARDO; C.A, TABOADA; PAGANI, M.A.

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2020

0895-9811

New and previous fossil remains and resulting biostratigraphy of the El ImperialFormation at Arroyo del Imperial, Quebrada de La Horqueta, and Cañón del Atuel keysections are analyzed, while the faunal relationships among them are clarified. Twodiachronnous faunas, the pTS and TSAIII associations, relatives to the TivertoniaStreptorhynchus assemblage are recognized and constrained to early late Bashkirian andMoscovian ages, respectively. These age assignments are supported by statistical analyses andavailable palynological and radiometric dating. Previous mentions of brachiopods fromArroyo del Imperial and Quebrada de La Horqueta are elucidated with the identification ofBuxtonia cf. riojanae (Leanza), Streptorhynchus inaequiornatus Leanza, Spiriferellina? sp.,Septosyringothyris (Precosyringothyris) aff. jaguelensis Lech, Septosyringothyris(Precosyringothyris) cf. feruglioi (Amos), Saltospirifer guevarai Cisterna and Archbold andPericospira sp. A new marine fauna from the upper part of the Cañón del Atuel section(Cabecera del Cañón Member) is reported. It includes the brachiopods Argentiella cf. A.stappenbecki Archbold, Cisterna and Sterren, Oehlertella annae (Feruglio), Orbiculoideasaltensis Reed, Calytrixia piersoni Taboada, Coolkilella aredesi Taboada, Costatumulus sp.and Septosyringothyris? sp. A bio-chronostratigraphic correlation scheme, including keylithostratigraphic units and biozones of central-western Argentina is updated.