The Neuquén Group is a group

Geologic unit

A geological unit is a volume of rock or ice of identifiable origin and age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features that characterize it....

 of geologic formation

Geologic formation

A formation or geological formation is the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties...

s found in Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

. Rocks in the Neuquén Group fall within the Cenomanian

Cenomanian

The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding...

 to early Campanian

Campanian

The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...

 stages of the Late Cretaceous

Late Cretaceous

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

 Period, about 100 million to 80 million years in age. It overlies the older Lohan Cura Formation

Lohan Cura Formation

The Lohan Cura Formation is a geologic formation with outcrops in the Argentine provinces of Río Negro, Neuquén, and Mendoza. It is the second oldest Cretaceous terrestrial formation in the Neuquén Basin....

 and is itself overlain by the younger Allen Formation

Allen Formation

The Allen Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous The Allen Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous The Allen Formation is a geological formation in Argentina whose strata date back to the...

 of the Malargüe Group

Malargüe Group

The Malargüe Group is a group of geologic formations found in Argentina. Rocks in the Malargüe Group fall within the late Campanian to Danian stages of the Late Cretaceous Period, about 80 million to 61.7 million years in age...

, separated from both by unconformities

Unconformity

An unconformity is a buried erosion surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger, but the term is used to describe...

.

Deposits have been located in the provinces

Provinces of Argentina

Argentina is subdivided into twenty-three provinces and one autonomous city...

 of Río Negro

Río Negro Province

Río Negro is a province of Argentina, located at the northern edge of Patagonia. Neighboring provinces are from the south clockwise Chubut, Neuquén, Mendoza, La Pampa and Buenos Aires. To the east lies the Atlantic Ocean.Its capital is Viedma...

, Neuquén

Neuquén Province

Neuquén is a province of Argentina, located in the west of the country, at the northern end of Patagonia. It borders Mendoza Province to the north, Rio Negro Province to the southeast, and Chile to the west...

, and Mendoza

Mendoza Province

The Province of Mendoza is a province of Argentina, located in the western central part of the country in the Cuyo region. It borders to the north with San Juan, the south with La Pampa and Neuquén, the east with San Luis, and to the west with the republic of Chile; the international limit is...

. Although several different types of environments are represented in various sections of the Neuquén Group, the dominant regime is alluvial deposition. Many dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s and other fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s have been discovered in these sediments.

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.

Neuquén Group strata, ordered from youngest to oldest

• Río Colorado
  Colorado River (Argentina)
  The Colorado River is a river in the south of Argentina.The Colorado river marks most of the political limit between the provinces of Neuquén and Mendoza, and between Rio Negro and La Pampa...
  
   Subgroup (Santonian
  Santonian
  The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series. It spans the time between 85.8 ± 0.7 mya and 83.5 ± 0.7 mya...
  
   to early Campanian)
  • Anacleto Formation
    Anacleto Formation
    The Anacleto Formation is a geologic formation with outcroppings in the Argentine Patagonian provinces of Mendoza, Río Negro, and Neuquén. It is the youngest formation within the Neuquén Group and belongs to the Río Colorado Subgroup...
    
     (early Campanian)
  • Bajo de la Carpa Formation
    Bajo de la Carpa Formation
    The Bajo de la Carpa Formation is a geologic formation that outcrops in Patagonia, in the provinces of Río Negro and Neuquén, Argentina. It is the first of two formations belonging to the Río Colorado Subgroup within the Neuquén Group...
    
     (Santonian)
• Río Neuquén
  Neuquén River
  The Neuquén River is the second most important river of the province of Neuquén in the Argentine Patagonia, after the Limay River.The river is born at the northwest of the province at an altitude of 2,300 metres, to be feed by a number of streams through valleys of the lower Andes while advancing...
  
   Subgroup (late Turonian to Coniacian
  Coniacian
  The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series and spans the time between 89.3 ± 1 Ma and 85.8 ± 0.7 Ma...
  
  )
  • Plottier Formation
    Plottier Formation
    The Plottier Formation is a geologic formation that outcrops in the Argentine Patagonian provinces of Río Negro and Neuquén. It is the younger of two formations belonging to the Río Neuquén Subgroup within the Neuquén Group, with the oldest rocks dating from the late Coniacian and its youngest...
    
     (late Coniacian ?to early Santonian)
  • Portezuelo Formation
    Portezuelo Formation
    The Portezuelo Formation is a geologic formation outcropping in the Mendoza, Río Negro and Neuquén provinces of Argentina. It is the fourth-oldest formation in the Neuquén Group and the older of the two formations in the Río Neuquén Subgroup...
    
     (late Turonian to early Coniacian)
• Río Limay
  Limay River
  The Limay River is an important river in the northwestern Argentine Patagonia . It is born at the eastern end of the Nahuel Huapi Lake and flows in a meandering path for about 380 km, collecting the waters of several tributaries, such as the Traful, the Pichileufú and the Collón Curá. It then meets...
  
   Subgroup (Cenomanian to early Turonian
  Turonian
  The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...
  
  )
  • Cerro Lisandro Formation
    Cerro Lisandro Formation
    The Lisandro Formation, alternatively known as the Cerro Lisandro Formation, is a geologic formation with outcrops in the Neuquén province of Argentina. It is the youngest formation within the Río Limay Subgroup, the lowest section of the Neuquén Group...
    
     (late Cenomanian to early Turonian)
  • Huincul Formation
    Huincul Formation
    The Huincul Formation is a geologic formation that outcrops in Río Negro and Neuquén provinces of Argentina. It is the second formation in the Río Limay Subgroup, the oldest subgroup within the Neuquén Group...
    
     (late Cenomanian)
  • Candeleros Formation
    Candeleros Formation
    The Candeleros Formation is a geologic formation that outcrops in Río Negro, Neuquén, and Mendoza provinces of Argentina. It is the oldest formation in the Neuquén Group and belongs to the Rio Limay Subgroup...
    
     (early Cenomanian)

South of Añelo

Añelo

Añelo is a second category municipality located in the Añelo Department in Neuquén Province, Argentina.- Economy :The economy of Añelo is based in agriculture...

, taking the road between Lake Los Barreales and the Neuquén River will provide splendid views on the successively younger formations, starting with the Cerro Lisandro Formation to the lake's northwest, and finally crossing the Anacleto Formation about 35 km down the road near the lake's eastern tip. The older strata are exposed south of Lake Los Barreales.