Neuquén Group

The Neuquén Group is a group of geologic formations found in Argentina. Rocks in the Neuquén Group fall within the Cenomanian to early Campanian stages of the Late Cretaceous Period. It overlies the older Lohan Cura Formation and is itself overlain by the younger Allen Formation of the Malargüe Group, separated from both by unconformities, dated to 98 and 79 Ma respectively.[1]

Neuquén Group
Stratigraphic range: Early Cenomanian-Early Campanian
~98–79 Ma
Almost the whole extent of the Neuquén Group is exposed between Lake Los Barreales and the bend of the Neuquén River in the center of this photo.To the lower left of the lake, a swath of light yellowish sandstones of the group's Huincul Formation are visible.
TypeGroup
Sub-units Río Colorado Subgroup
 Anacleto Formation
 Bajo de la Carpa Formation

Río Neuquén Subgroup
 Plottier Formation
 Portezuelo Formation

Río Limay Subgroup
 Lisandro Formation
 Huincul Formation
 Candeleros Formation
UnderliesMalargüe Group
 Allen Formation
OverliesLohan Cura Formation
Thickness500 m (1,600 ft)
Location
Coordinates38.5°S 68.7°W / -38.5; -68.7
Approximate paleocoordinates44.4°S 47.2°W / -44.4; -47.2
RegionRío Negro, Neuquén & Mendoza Provinces
Country Argentina
ExtentNeuquén Basin
Type section
Named forNeuquén
Neuquén Group (Argentina)

Description

Deposits have been located in the provinces of Río Negro, Neuquén, and Mendoza. Although several different types of environments are represented in various sections of the Neuquén Group, the dominant regime is alluvial deposition. Many dinosaurs and other fossils have been discovered in these sediments.

Subdivision

There are seven formations within the Neuquén Group. These are divided into three subgroups named after major rivers in the area. In some works, the subgroups themselves are treated as formations and what usually is considered to be the formations as mere members of these. However, particularly in the Río Limay Subgroup, the formations are clearly composed of very distinct rocks.[2]

Neuquén Group strata, ordered from youngest to oldest

South of Añelo, taking the road between Lake Los Barreales and the Neuquén River will provide splendid views on the successively younger formations, starting with the Lisandro Formation to the northwest of Lake Los Barreales, and finally crossing the Anacleto Formation about 35 kilometres (22 mi) down the road near the eastern tip of the lake. The older strata are exposed south of Lake Los Barreales.[2]

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See also

References
  1. Leanza et al., 2004, p.63
  2. Sánchez et al. (2006)

Bibliography
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