Corral de Piedra: Late Maastrichtian, Argentina
collected 2020

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Lycopodiopsida - Selaginellales
Ceratosporites equalis Cookson and Dettmann 1958
Lycopodiopsida - Lycopodiales
Algae - Zygnemataceae
Ovoidites sp. Krutzsch 1959
Ovoidites parvus Nakoman 1966
Angiospermae - Proteales - Proteaceae
Angiospermae - Asterales - Asteraceae
Tubulifloridites lilliei Farabee and Canright 1986
Coniferales - Podocarpaceae
Podocarpidites spp. Cookson 1947
Polypodiopsida - Gleicheniaceae
see common names

Geography
Country:Argentina State/province:Chubut
Coordinates: 45.6° South, 68.4° West (view map)
Paleocoordinates:45.5° South, 57.5° West (Wright 2013)
Basis of coordinate:based on nearby landmark
Geographic resolution:outcrop
Time
Period: Cretaceous Epoch: Late Cretaceous
Stage: Maastrichtian 10 m.y. bin: Cretaceous 8
Key time interval: Late Maastrichtian
Age range of interval: 72.2 - 66 m.y. ago
Stratigraphy
Geological group:Chubut Formation:Lago Colhué Huapi
Stratigraphic resolution:bed
Stratigraphy comments: Uppermost Lago Colhué Huapi Formation. Geological studies—particularly those of palynomorphs—support a late Maastrichtian age, probably close to the Cretaceous/Paleogene boundary, for the stratigraphic horizon in question (Vallati et al., 2016, 2020).
Lithology and environment
Primary lithology:massive,planar lamination,black mudstone
Secondary lithology: sandstone
Includes fossils?Y
Lithology description: The sedimentary deposits that are partially outcropping in Corral de Piedra include alternation of claystones, siltstones, and sandstones. The mudstone deposits that include the palynomorphs are massive to horizontally laminated, 0.2–3.2 m thick, interpreted as the deposit of suspended particles in a dilute flow. The sandstones are medium to fine grain, gray-colored and with a diffuse horizontal lamination. This sandstone bed has a flat base and top and is 0.18–0.9 m thick, being interpreted as a traction deposit in low flow conditions.
Environment:fluvial indet.
Taphonomy
Modes of preservation:soft parts
Size of fossils:macrofossils
Preservation of anatomical detail:good
Abundance in sediment:common
Articulated whole bodies:none
Associated major elements:none
Disassociated major elements:some
Disassociated minor elements:many
Fragmentation:none
Bioerosion:none
Encrustation:none
Collection methods and comments
Collection excludes:all microfossils
Collection methods:hydrochloric,hydroflouric,field collection
Reason for describing collection:general faunal/floral analysis
Collection dates:2020
Collection method comments: The samples were processed using the standard palynological procedures, with dilute hydrochloric acid (19%) and hydrofluoric acid (70%) to remove respectively carbonate and silicate mineral components, followed by treatment in hot hydrochloric acid (37%). Occasionally, a brief oxidation of the residue with nitric acid was necessary in order to improve the results. The palynological slides were studied under a Carl Zeiss KF 2 microscope, and the micrographs were taken with a digital Nikon Coolpix P2 camera at the Biostratigraphic Laboratory of the Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB). The slides are housed in the micropalaeontological repository at the UNPSJB, under the initials UNPSJB-MFP-CV181-221
Metadata
Also known as:Headwaters of the Río Chico
Database number:234016
Authorizer:E. Vlachos Enterer:F. Aspromonte
Research group:paleobotany
Created:2024-03-12 09:25:20 Last modified:2025-02-22 15:12:02
Access level:the public Released:2024-03-12 09:25:20
Creative Commons license:CC0
Reference information

Primary reference:
87814. P. Vallati, A. De Sosa Tomas, and G. Casal. 2020. A Maastrichtian terrestrial palaeoenvironment close to the K/Pg boundary in the Golfo San Jorge basin, Patagonia, Argentina. Journal of South American Earth Sciences 97(102401) [E. Vlachos/F. Aspromonte]