scholarly journals U-Pb geochronology of the Santa Cruz Formation (early Miocene) at the Río Bote and Río Santa Cruz (southernmost Patagonia, Argentina): Implications for the correlation of fossil vertebrate localities

2016 ◽  
Vol 70 ◽  
pp. 198-210 ◽  
Author(s):  
José I. Cuitiño ◽  
Juan Carlos Fernicola ◽  
Matthew J. Kohn ◽  
Robin Trayler ◽  
Maximiliano Naipauer ◽  
...  
2019 ◽  
Vol 46 (2) ◽  
pp. 383
Author(s):  
José I. Cuitiño ◽  
Sergio F. Vizcaíno ◽  
M. Susana Bargo ◽  
Inés Aramendía

Lago Posadas is located at the foot of the Southern Patagonian Andes, in southwestern Argentina, where the early Miocene Santa Cruz Formation (SCF) shows thick and laterally continuous exposures. This region has been scarcely explored for fossil vertebrates since the first efforts by J.B. Hatcher in 1898-99. In this contribution, we performed sedimentologic and paleontological studies in order to reconstruct depositional environments and the associated fossil vertebrate fauna. Sedimentologic data suggest that the sedimentary record begins with restricted marine-estuarine deposits grading upward to fluvial floodplains and fluvial channels. Extensive floodplains, occasionally interrupted by low-sinuosity, sand-dominated channels, show dominant reddish coloration, moderate to low paleosol development, abundant crevasse splay sandstones and lack of vegetal remains, suggesting deposition in a low gradient, oxygenated setting under elevated sedimentation rates. Vertical stratigraphic trends are subtle, suggesting little paleoenvironmental changes during deposition of the whole SCF in this region. Paleocurrent directions, sandstone composition and paleogeographic reconstructions all indicate that deposition of the SCF was strongly associated to the contemporaneous uplift of the Andes. Fossil vertebrates analyzed are the result of our collecting effort and revision of museum collections. The faunal assemblage includes 31 taxa: 28 mammals and three birds. Mammals belong to the main groups recorded in other areas of the SCF (metatherians, xenarthrans, notoungulates, litopterns, astrapotheres and rodents). The assemblage allows a Santacrucian Age sensu lato assignment for the fauna at Lago Posadas. Taxonomic revisions of several taxa are necessary to further adjust the biostratigraphic significance of this association. The combined record of arboreal, browser and frugivores, on one side, and grazer mammals and rheas, on the other, suggest the presence of both trees and open environments. Frugivores, among primary consumers, and the secondary consumers guild are under-represented due to sample and fossil remain size biases. The sedimentologic and paleontological record of the SCF in Lago Posadas suggests that the uplift of the Southern Patagonian Andes acted as a primary control on basin subsidence and sediment supply, providing a special signature for sub-andean localities. However, previously registered climatic changes are poorly recorded in this study.


PalZ ◽  
2016 ◽  
Vol 90 (3) ◽  
pp. 647-648
Author(s):  
Diego Brandoni ◽  
Laureano González Ruiz ◽  
Marcelo F. Tejedor ◽  
Gabriel Martin ◽  
John G. Fleagle
Keyword(s):  

2017 ◽  
Vol 183 (3) ◽  
pp. 334-347 ◽  
Author(s):  
Mariana Brea ◽  
Alejandro F. Zucol ◽  
M. Susana Bargo ◽  
Juan Carlos Fernicola ◽  
Sergio F. Vizcaíno
Keyword(s):  

2015 ◽  
Vol 89 (5) ◽  
pp. 748-761 ◽  
Author(s):  
Sergio E. Miquel ◽  
Pablo E. Rodriguez

AbstractA remarkable fossil assemblage composed of five gastropod taxa is described from the Early Miocene of Santa Cruz (Patagonia, Argentina) in southernmost South America. The assemblage includes extinct and living genera South America, and on geographic distributions and represent background new information on spatial and across time distributions as well as identification of new taxa. A new taxon,Patagocharopa enigmatican. gen. n. sp., is tentatively assigned to Charopidae.Gastrocopta patagonican. sp. (Vertiginidae) represents the oldest record ofGastrocoptain Argentina and the southernmost record for the Americas.Punctum patagonicumn. sp. (Punctidae) represents the first record ofPunctumfor continental South America, and characterized by a protoconch with traces of axial costulae and a teleoconch with strong radial ribs.Zilchogyra miocenican. sp. is the first Miocene record of the charopid genusZilchogyra. Fragments of a possibleScolodonta(Scolodontidae) are recorded. Overall, the assemblage represents an important and useful paleoenvironmental tool. This fauna suggests that a more temperate and humid environment than today—with a more dense vegetation cover—was prevalent at this site during the Early Miocene.


1994 ◽  
Vol 68 (2) ◽  
pp. 279-286 ◽  
Author(s):  
Amalia M. Olivera ◽  
William J. Zinsmeister ◽  
S. Graciela Parma

A new Tertiary gastropod genus, Peonza n. gen., is described, along with two new species, P. torquata from southern Argentina and P. benjamina from southern Chile. These muricacean gastropods, of uncertain familial status, occur in the late Eocene San Julián Formation and in the late Oligocene to early Miocene? Monte León Formation, Santa Cruz Province, Argentina. They also were recorded in the (probably) Oligocene Magellanian beds in Tierra del Fuego, Argentina, and in early Miocene deposits of the Tres Montes region in the Chilean Canals. In spite of the small number of specimens, Peonza n. gen. seems to have had a wide geographic and temporal distribution.


2011 ◽  
Vol 85 (6) ◽  
pp. 1181-1187 ◽  
Author(s):  
Diego Urteaga ◽  
Miguel Griffin ◽  
Guido Pastorino

A new species of chiton is described from early Miocene deposits of the Monte León Formation, in Santa Cruz Province, Argentina. Callochiton monteleonensis n. sp. clearly differs from known fossil and Recent species of the southwestern Atlantic because the central area of its intermediate valves has a stepped appearance, in which each step is marked by a longitudinal rib. It is similar to Callochiton kapitiensis Mestayer, 1926, a Recent species from New Zealand. Biogeographic implications are discussed. This is the first record of a polyplacophoran from Neogene deposits of Argentina.


Sign in / Sign up

Export Citation Format

Share Document