INVESTIGADORES
FERNICOLA Juan Carlos
congresos y reuniones científicas
Título:
Rincón del Buque: A Largely unexplored rich Santacrucian (Early Miocene) locality in southern Patagonia, Argentina.
Autor/es:
BARGO, M. S.; VIZCAÍNO, S. F.; KAY, R. F.; FERNICOLA, J. C.; RAIGEMBORN, M. S.; KRAPOVICKAS, V.; TOLEDO, N.; MUÑOZ, N. A.
Lugar:
Mendoza
Reunión:
Congreso; 4th International Palaeontological Congress; 2014
Institución organizadora:
International Palaeontological Association
Resumen:
The early Miocene deposits of the Santa Cruz Formation (SCF;
Santacrucian Age), widely distributed in Southern Patagonia (Argentina),
contain a rich assemblage of fossil mammals. The best-known fossiliferous
exposures of SCF crop out along the Atlantic coastline of Santa Cruz Province,
between Río Santa Cruz southward to Río Coyle and then to Río Gallegos.
Localities south to Río Coyle haven been extensively studied in the last 20
years, but those to the north have received less attention. Isolated geological
and paleontological studies for Cerro Observatorio and Monte León were
performed in the 1990s, but a third major area, Rincón del Buque (= Media
Luna), first reported in the 1920s has been neglected. This locality is of
interest because it records the basal contact between the SCF and the
underlying shallow marine Monte Léon Formation, a contact that is not exposed
south to the Río Coyle, and because it is particularly rich in fossil
vertebrates which are briefly mentioned in a short report in 1941. Since 2009,
several field seasons to Rincón del Buque by the authors allow us to
reconstruct the depositional paleoenvironments based on detailed stratigraphic
profiles with sedimentological and ichnological data, and to make a large
collection of vertebrates (~300 specimens). At Rincón del Buque there is a
progradational succession, beginning with a marginal-marine-estuarine setting
that transitions gradually to fluvial deposits. About 80% of the vertebrates
were recovered in situ in two different tuff beds: a lower marine-bioturbated
tuff immediately above the last oyster bed (the latter marking the top of the
Monte León Formation), and a second tuffaceous bed at ~30 meters from the base
deposited in a freshwater fluvial setting. The rest of the specimens come from
surface collection at different levels. Specimens recorded belong to
Calyptocephalellidae (Anura), Testudines, Phorusrhacidae (Aves),
Paucituberculata and Sparassodonta (Marsupialia), Cingulata and Pilosa
(Xenarthra), Toxodontia and Typotheria (Notoungulata), Litopterna, and
Astrapotheria, Chinchilloidea, Cavioidea and Octodontoidea (Rodentia), and
Primates. Most genera and/or species preliminarily identified have been
previously recorded in the SCF, particularly in coastal localities south of Río
Coyle. Rincón del Buque may hold the key to establishing details of faunal
transitions in different areas where SCF crops out. On one hand connections are
established between the lowermost levels north of Río Coyle and higher levels
to the south, along the Atlantic coast, and on the other hand between the
costal localities collectively and those of the Río Santa Cruz to the
northwest.