Portezuelo Formation

The Portezuelo Formation is a geologic formation of Late Cretaceous (Late Turonian to Early Coniacian) age, outcropping in the Mendoza, Río Negro and Neuquén provinces of Argentina.[1] It is the fourth-oldest formation in the Neuquén Group and the older of the two formations in the Río Neuquén Subgroup. Formerly, that subgroup was treated as a formation, and the Portezuelo Formation was known as the Portezuelo Member.[2]

Portezuelo Formation
Stratigraphic range: late Turonian-early Coniacian
~90.5–88.5 Ma
TypeGeological formation
Unit ofNeuquén Group
 Río Neuquén Subgroup
UnderliesLos Bastos Formation
OverliesLisandro Formation
Thickness95–130 m (312–427 ft)
OtherConglomerate, limestone
Coordinates38°30′S 68°42′W / 38.5°S 68.7°W / -38.5; -68.7
Approximate paleocoordinates44°24′S 47°12′W / 44.4°S 47.2°W / -44.4; -47.2
RegionMendoza, Río Negro & Neuquén Provinces
ExtentNeuquén Basin
Type section
Named forSierra del Portezuelo
Portezuelo Formation is located in Argentina
Portezuelo Formation
Portezuelo Formation (Argentina)


The type locality of the Portezuelo Formation is the mountain range known as Sierra del Portezuelo in Neuquén Province.[3] This formation conformably overlies the Lisandro Formation of the Río Limay Subgroup. In the top layers it grades into the Plottier Formation, the younger formation within the Río Neuquén Subgroup.

Sandstones and siltstones, probably deposited under fluvial conditions, make up the Portezuelo Formation. There are also occasional cemented claystone deposits, as well as numerous paleosols (fossil soils). The formation varies between 95 and 130 metres (312 and 427 ft) thick throughout its range.[2][4]

Fossil contentEdit

Many dinosaur fossils have recently been described from this formation, as well as remains of several other types of animals:

See alsoEdit


  1. ^ a b Portezuelo Formation at Fossilworks.org
  2. ^ a b Sánchez et al., 2006
  3. ^ Wichmann, 1929
  4. ^ Leanza et al., 2004
  5. ^ a b c d Agnolin et al., 2006
  6. ^ Porfiri et al., 2007
  7. ^ Paulina-Carabajal and Currie, 2017
  8. ^ Baiano, Mattia A.; Pol, Diego; Bellardini, Flavio; Windholz, Guillermo J.; Cerda, Ignacio A.; Garrido, Alberto C.; Coria, Rodolfo A (2022-09-05). "Elemgasem nubilus: a new brachyrostran abelisaurid (Theropoda, Ceratosauria) from the Portezuelo Formation (Upper Cretaceous) of Patagonia, Argentina". Papers in Palaeontology. 8 (5): e1462. doi:10.1002/spp2.1462.