Estancia 25 de Mayo (VG9) (Cretaceous of Argentina)

Also known as South of Lago Argentino

Where: Santa Cruz, Argentina (50.4° S, 72.2° W: paleocoordinates 52.4° S, 62.0° W)

• coordinate stated in text

• local area-level geographic resolution

When: Calafate Formation, Late/Upper Maastrichtian (70.6 - 66.0 Ma)

Environment/lithology: coastal; lithified, sandy sandstone and lithified, muddy, conglomeratic mudstone

• The general characteristics of the sediments together with the low diversity of dinoflagellate cysts suggest a nearshore marine environment, the geometry of the basin that these deposits fill has not yet been determined. Therefore, the existence of an estuarine or incised valley cannot be proved, even though this is the most likely palaeogeographical interpretation.
• The Calafate Formation is bounded by unconformities and therefore at Estancia 25 de Mayo variable thickness have been recorded. This is dominated by sandstones with occasional beds of conglomerates and very few mudstones. The exposures show at least four sandy–conglomeratic beds, each 10–30 m thick, that form vertical cliffs. These intervals are separated by 30–50-m-thick intervals of finer-grained brownish sediments that are less steeply inclined, thus leading to good soil development and poor exposures.

Size class: microfossils

• Common parts: Dinoflagellate cysts.

Preservation: soft parts

Collection methods: hydrochloric, hydroflouric,

• The figured specimens are housed in the Palynological Collection, Departamento de Geología, Universidad Nacional del Sur, Bahía Blanca, Argentina.

•Samples were collected from fine-grained lithologies whenever possible because the predominantly coarse-grained deposits are not suitable for palynological studies.

Primary reference: S. Marenssi, V. Guler, S. Casadío, R. Guerstein, and O. Papú. 2004. Sedimentology and palynology of the Calafate Formation (Maastrichtian), Austral Basin, Southern Patagonia, Argentina. Cretaceous Research 25(6):907-918 [C. Jaramillo/J. Moreno/F. Aspromonte]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 232649: authorized by Evangelos Vlachos, entered by Franco Aspromonte on 15.12.2023

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Dinophyceae
  -
Spiniferites ramosus
Spiniferites ramosus Lentin and Williams 1973
 Peridiniales - Peridiniaceae
Cerodinium sp., Alterbidinium acutulum
Cerodinium sp. Vozzhennikova 1963
Alterbidinium acutulum Lentin and Williams 1985
 Peridiniales - Deflandreaceae
Palaeocystodinium lidiae
 Gonyaulacales - Gonyaulacaceae
Impagidinium sp., Operculodinium centrocarpum, Oligosphaeridium pulcherrimun
Impagidinium sp. Stover and Evitt 1978
Oligosphaeridium pulcherrimun Davey and Williams 1966
 Gonyaulacales -
Tanyosphaeridium xanthiopyxides
Tanyosphaeridium xanthiopyxides Stover and Evitt 1978
 Dinoflagellata -
Spongodinium sp.
Spongodinium sp. Deflandre 1936