Sierra Baguales: Burdigalian, Chile

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Mammalia - Notoungulata - Toxodontidae
Nesodon sp. Owen 1846
Adinotherium sp. Ameghino 1887
Mammalia - Notoungulata - Notohippidae
Notohippinae (aff. Notohippus) toxodontoides Ameghino 1890
Mammalia - Rodentia - Neoepiblemidae
Perimys incavatus Ameghino 1902
Mammalia - Rodentia
Cavioidea indet. Fischer de Waldheim 1817
Adelphomys candidus Ameghino 1887
Mammalia - Dasypodidae
Proeutatus informal sp. nov. Ameghino 1891
Proeutatus sp. Ameghino 1891
Mammalia - Megalonychidae
Megalonychidae indet. Gervais 1855
Mammalia - Tardigrada
Tardigrada indet. (Latham and Davies 1795)
replaced by Folivora
Mammalia - Propalaehoplophoridae
Propalaehoplophorinae indet. (Ameghino 1891)
original and current combination Propalaehoplophoridae
Mammalia - Ungulata - Proterotheriidae
Proterotheriinae indet. Ameghino 1885
Paramacrauchenia scamnata Ameghino 1902
Mammalia - Ungulata - Astrapotheriidae
Astrapotheriinae indet. Soria and Alvarenga 1989
Astrapothericulus iheringi (Ameghino 1899)
Coniferales - Podocarpaceae
Podocarpaceae indet. Endlicher 1847
Poales - Poaceae
Poaceae indet. Barnhart 1895
Pteridopsida - Cyatheales - Cyatheaceae
Cyatheaceae indet. Kaulfuss
Magnoliopsida - Myrtales - Myrtaceae
Myrtaceae indet. de Jussieu 1789
Magnoliopsida - Myrtales - Onagraceae
Onagraceae indet. de Jussieu 1789
Magnoliopsida - Caryophyllales - Chenopodiaceae
Chenopodiaceae indet. Ventenat
Magnoliopsida - Proteales - Proteaceae
Proteaceae indet. de Jussieu 1789
Magnoliopsida - Asterales - Asteraceae
Asteraceae indet. von Berchtold and Presl 1820
Magnoliopsida - Fagales - Nothofagaceae
Nothofagaceae indet. Kuprian 1962
unclassified
Skolithos sp. Haldemann 1840
see common names

Geography
Country:Chile State/province:Magallanes
Coordinates: 50.6° South, 72.5° West (view map)
Paleocoordinates:51.4° South, 66.5° West
Basis of coordinate:estimated from map
Geographic resolution:outcrop
Time
Period:Neogene Epoch:Miocene
Stage:Burdigalian 10 m.y. bin:Cenozoic 5
Key time interval:Burdigalian
Age range of interval:20.44000 - 15.97000 m.y. ago
Stratigraphy
Formation:Santa Cruz
Stratigraphic resolution:group of beds
Stratigraphy comments: The lithological correlation is also confirmed by detrital zircon ages (maximum age of 18.23±0.26 Ma) and a rich assemblage of terrestrial vertebrate fossils, biostratigraphically equivalent to a post- Colhuehuapian, pre-Santacrucian South American Land Mammal Age (SALMA) fauna, suggesting a range of 19 to 17.8 Ma

Santa Cruz Formation (first refered by Ameghino (1889) as the ‘Piso Santacruceño’ (Marshall, 1976; Vizcaíno et al., 2012a) and later formalized by Zambrano and Urien (1970)), but Keidel and Hemmer in 1931 refered to this formation in Chile as Palomares.
The Santa Cruz Formation is exposed along the southern flank of Cerro Cono (Fig. 2), where it overlies the Estancia 25 de Mayo Formation with a conformable, gradational contact
Lithology and environment
Primary lithology: mudstone
Secondary lithology: sandstone
Includes fossils?Y
Includes fossils?Y
Lithology description: The descriptions are very long, this is a sum up: Unit 1 has a total thickness of 32.7 m. Overlying an erosional contact at the base is a 0.7 m thick, reddish brown, trough cross-laminated, medium- to coarse-grained sandstone, in which the troughs are up to about 1 m wide. Unit 2 has an erosional basal contact overlain by a 0.5 m thick, dark brown, medium-grained sandstone showing high-angle planar cross-lamination and mi- nor trough cross-lamination indicating northwest- to east-flowing currents. Unit 3, with a total thickness of 13.3 m, has a 1.0 m thick conglomerate at the base with small (up to 1 cm), multi-coloured chert and quartz clasts, grading towards the east into sandy conglomerate. Unit 4 starts with a 1.9 m thick, whitish, medium- grained sandstone at the base, which is low-angle planar cross-laminated. Unit 5 is 8.6 m thick and commences with a 4.6 m thick, yellowish, clay-rich, fine- to medium-grained sandstone with upper flow regime horizontal lami- nation, rare trough cross-lamination and high-angle cross-lamination Unit 6 has an erosional basal contact and a total thickness of 4.6 m, which can be subdivided into 5 fining-upward sub-units (6a-e) separated by sharp to erosional contacts. Fossils come from units 1-7
Environment:fluvial indet.
Geology comments: Santa Cruz Formation in this area was deposited in a continental, fluvial environment, as indicated by the abundance of terrestrial vertebrate fragments, Scoyenia including probable hymenopterid traces, multi-coloured (often reddish), blocky-weathering mudstones (Fig. 4) with occasional mud-cracks, and sandstones showing sedimentary structures such as trough, epsilon and high-angle planar cross-lamination (Fig. 5), with a more or less consistent paleocurrent direction towards the east-northeast
Taphonomy
Modes of preservation:body,trace
Size of fossils:macrofossils,mesofossils
Collection methods and comments
Reason for describing collection:general faunal/floral analysis
Metadata
Database number:204203
Authorizer:P. Mannion Enterer:M. Kouvari
Modifier:M. Kouvari
Created:2019-09-03 04:39:48 Last modified:2019-09-03 04:53:03
Access level:the public Released:2019-09-03 04:39:48
Creative Commons license:CC BY
Reference information

Primary reference:

69983. J. E. Bostelmann, J. P. Le Roux, A. Vásquez, N. M. Gutiérrez, J. L. Oyarzún, C. Carreño, T. Torres, R. Otero, A. Llanos, C. M. Fanning, and F. Hervé. 2013. Burdigalian deposits of the Santa Cruz Formation in the Sierra Baguales, Austral (Magallanes) Basin: Age, depositional environment and vertebrate fossils. Andean Geology 40(3):458-489 [P. Mannion/M. Kouvari]