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Neuquén Basin (Spanish: Cuenca Neuquina) is a sedimentary basin covering most of Neuquén Province in Argentina. The basin originated in the Jurassic and developed through alternating continental and marine conditions well into the Tertiary. The basin bounds to the west with the Andean Volcanic Belt, to the southeast with the North Patagonian Massif and to the northeast with the Sierra Pintada System.[1] The basin covers an area of approximately 120,000 square kilometres (46,000 sq mi).[2]

Neuquén Basin
Cuenca Neuquina
Map showing the location of Neuquén Basin
Map showing the location of Neuquén Basin
EIA Neuquen Basin.png
Map of Vaca Muerta showing the extend of the Neuquén Basin. Colors indicate hydrocarbon maturity as measured by vitrinite reflectance. Huincul Fault is shown in grey.
Coordinates38°14′S 69°16′W / 38.233°S 69.267°W / -38.233; -69.267
EtymologyNeuquén Province
LocationSouthern South America
Country Argentina
State(s)Neuquén Province
CitiesNeuquén, Bariloche
Characteristics
On/OffshoreOnshore
BoundariesAndean Volcanic Belt (W)
Sierra Pintada (N)
North Patagonian Massif (SE)
Part ofAndean foreland basins
Area120,000 km2 (46,000 sq mi)
Hydrology
River(s)Río Negro, Colorado
Lake(s)Ezquiel Ramos Mexía, Los Barreales & Mari Menuco Reservoirs
Geology
Basin typeForeland basin
PlateSouth American
OrogenyAndean
AgeTriassic-Holocene
StratigraphyStratigraphy
FaultsHuincul

Contents

DescriptionEdit

Jurassic and Cretaceous marine transgressions from the Pacific are recorded in the sediments of Neuquén Basin. These marine sediments belong to Cuyo Group, Tordillo Formation, Auquilco Formation and Vaca Muerta.[3] In the Late Cretaceous, conditions in the neighboring Andean orogeny changed. A marine regression occurred and the fold and thrust belts of Malargüe (36°00 S), Chos Malal (37° S) and Agrio (38° S) started to develop in the Andes and did so until Eocene times. This meant an advance of the Andean orogenic deformation since the Late Cretaceous that made the western part of Neuquén Basin to stack in the Malargüe and Agrio fold and thrust belts.[3][4] This caused a shift in deposition from Pacific to Early Atlantic.[5]

In the south of Mendoza Province, the Guañacos fold and thrust belt (36.5° S) appeared and grew in the Pliocene and Pleistocene consuming the western fringes of the Neuquén Basin.[3][4]

TectonicsEdit

The Huincul basement high or Huincul ridge (Spanish: dorsal de Huincul) is a geological structure that divides Neuquén Basin in two parts.[6][7] The basement high is one of the most studied features of Neuquén Basin given its importance for hydrocarbon exploration and exploitation.[7] All over the basement high runs an approximate length of 250 kilometres (160 mi).[7] There have been proposals on the nature of this structure. In the 1970s and 1980s it was proposed by that it was a transpressive fault zone.[6][7] Later Pángaro described it as being made up of inverted half-grabens.[7]

Unconformities have been registered in the basin and were dated at 98, 117, 123, 129, 134 and 154 Ma.[8]

StratigraphyEdit

The basin contains stratigraphic units from the Triassic onwards, with lateral variations assigned as different formations:

Cenozoic
Malargüe Group
Neuquén Group
Rayoso Group
Mendoza Group
Lotena Group
Cuyo Group
Choiyoi Group

Petroleum geologyEdit

The Neuquén Basin is an important oil and gas producing basin in Argentina. Production started in 1918 and accumulated to 5.84 MMBOE in 2004, representing 45% of the oil production in Argentina and 61% of its gas production.[9] The basin is also important for unconventionals, with the Vaca Muerta and Los Molles formations being major shale gas producers.

Source rock formations are predominantly the Vaca Muerta, and to a lesser extent the Agrio and Los Molles Formations. Reservoir rocks comprise the Mulichinco and Chachao Formations. Deeper reservoirs are the Lotena and Barda Negra Formations.[10] Regional seal rocks are the evaporites of the Auquilco and Huitrín Formations, with local seals the Vaca Muerta, Agrio and Catriel Formations.[11]

ReferencesEdit

  1. ^ "Cuenca Neuquina". Secretaría de Energía (in Spanish). Government of Argentina. Retrieved 30 November 2015.
  2. ^ Howell et al., 2005
  3. ^ a b c Rojas et al., 2016
  4. ^ a b Ramos & Mahlburg Kay, 2006
  5. ^ Ponce et al., 2015, p.10
  6. ^ a b Mosquera & Ramos, 2006
  7. ^ a b c d e Pángaro et al., 2009
  8. ^ Leanza, 2017, p.150
  9. ^ Mendiberri et al., 2004, p.1
  10. ^ Ponce et al., 2015, p.28
  11. ^ Ponce et al., 2015, p.29

BibliographyEdit

Further readingEdit