Neuquén Basin

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 San Rafael Block and to the east with the Sierra Pintada System.[1] The basin covers an area of approximately 120,000 square kilometres (46,000 sq mi).[2] One age of the SALMA classification, the Colloncuran, is defined in the basin, based on the Collón Curá Formation, named after the Collón Curá River, a tributary of the Limay River.

Neuquén Basin
Cuenca Neuquina
Map showing the location of Neuquén Basin
Map showing the location of Neuquén Basin
EIA Neuquen Basin
Map of Vaca Muerta showing the extent 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
EtymologyNeuquén River
LocationSouthern South America
Country Argentina
 Chile
State(s)Mendoza, Río Negro, La Pampa, & Neuquén Provinces
Araucanía & Bío Bío Regions
CitiesNeuquén, Bariloche
Characteristics
On/OffshoreOnshore
BoundariesAndean Volcanic Belt (W)
San Rafael Block (NE)
Sierra Pintada (E)
North Patagonian Massif (SE)
Part ofAndean foreland basins
Area120,000 km2 (46,000 sq mi)
Hydrology
River(s)Río Negro, Colorado, Limay, Collón Curá & Neuquén Rivers
Lake(s)Ezquiel Ramos Mexía, Los Barreales & Mari Menuco Reservoirs
Geology
Basin typeForeland basin
PlateSouth American
OrogenyAndean
AgeTriassic-Holocene
StratigraphyStratigraphy
FaultsHuincul
Field(s)a.o. Vaca Muerta (unconventional oil)

Description

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]

Tectonics

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] In 2009, 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]

Stratigraphy

Rio Negro Argentina map
Map of the Río Negro watershed. The Neuquén Basin comprises the upper course of the Río Negro, stretching towards the Colorado River in the north and to the Limay River in the south.
Various stratigraphic units are named after these rivers and their tributaries.

The basin contains many stratigraphic units from the Triassic onwards, with large regional variations from east to west and north to south, often described as different formations that are laterally equivalent, this list is a comprehensive overview of described formations:

Cenozoic
Mesozoic
Paleozoic
  • Choiyoi Group (Late Permian-Mid Triassic)[9]
    • El Palque Formation
    • Horcajos Formation
    • Portezuelo del Cenizo Formation
    • Tambillos Formation
    • Vega de Los Machos Formation

Petroleum geology

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.[40] 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.[41] Regional seal rocks are the evaporites of the Auquilco and Huitrín Formations, with local seals the Vaca Muerta, Agrio and Catriel Formations.[42]

Notes and references

Notes

  1. ^ Some authors include the Agua de la Piedra Formation within the Malargüe Group, others do not
  2. ^ Some authors include the Tordillo Formation within the Mendoza Group, others do not
  3. ^ Some authors include the Los Molles Formation within the Cuyo Group, others do not

References

  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. ^ a b c d e f g h i j k l m n o p q r s t u Onnis et al., 2018, p.38
  10. ^ a b c d e f g h Hoja Geológica 3969-II, 2007, p.6
  11. ^ Kramarz et al., 2005, p.276
  12. ^ Escosteguy & Franchi, 2010, p.425
  13. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad Lebinson et al., 2018, p.252
  14. ^ a b Escosteguy & Franchi, 2010, p.426
  15. ^ a b c d e f g h i j k l m n o p q r s t u Balgord, 2017, p.455
  16. ^ Escosteguy & Franchi, 2010, p.423
  17. ^ a b c d e Náñez & Malumián, 2019, p.186
  18. ^ Escosteguy & Franchi, 2010, p.422
  19. ^ Kramarz et al., 2015, p.586
  20. ^ Agnolin & Chafrat, 2015
  21. ^ a b Escosteguy & Franchi, 2010, p.421
  22. ^ Wilf et al., 2005
  23. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak Balgord & Carapa, 2014, p.6
  24. ^ Garrido, 2011, p.237
  25. ^ Garrido, 2011, p.236
  26. ^ Escosteguy & Franchi, 2010, p.420
  27. ^ a b c d e f g h Gómez Dacal et al., 2018, p.113
  28. ^ Ponce et al., 2015, p.16
  29. ^ a b c d e f g Olivo et al., 2016, p.218
  30. ^ Voglino, 2017
  31. ^ Ponce et al., 2015, p.18
  32. ^ Iñigo et al., 2018
  33. ^ Ponce et al., 2015, p.27
  34. ^ Geologic Map, 2007, p.147
  35. ^ Mescua et al., 2013, p.105
  36. ^ a b Ponce et al., 2015, p.17
  37. ^ a b c Zavala, 1993, p.74
  38. ^ a b Zavattieri & Mego, 2008, p.484
  39. ^ Geologic Map, 2007, p.144
  40. ^ Mendiberri et al., 2004, p.1
  41. ^ Ponce et al., 2015, p.28
  42. ^ Ponce et al., 2015, p.29

Bibliography

Geologic map
General
Mesozoic
Vaca Mahuida Formation
Ventana Formation
Chichinales Formation
Cerro Bandera Formation

Further reading

Agrio Formation

The Agrio Formation is an Early Cretaceous geologic formation that is up to 1,500 metres (4,900 ft) thick and is located in the southern Mendoza Province and northern-central Neuquén Province, in the Neuquén Basin of northwestern Patagonia, Argentina. This formation is the youngest one of the Mendoza Group, overlying the Mulichinco and Bajada Colorada Formations and overlain by the Huitrín and La Amarga Formations. It is dated to the Late Valanginian to Early Hauterivian, Late Valanginian to Early Barremian, or Hauterivian to earliest Aptian.The Agrio Formation is considered the third most important source rock in the hydrocarbon-rich Neuquén Basin, after the Vaca Muerta Formation and Los Molles Formation. Similarly to these older units, it is potentially a source of shale gas.

This formation has provided fossils of ichthyosaurs, ammonites, gastropods, bivalves, decapods, echinoderm, corals and fish. The newly described species of fish, Tranawuen agrioensis, the ammonite Holcoptychites agrioensis, and the bivalve Pholadomya agrioensis have been named after the formation.

Amargasuchus

Amargasuchus is an extinct genus of crocodylomorph. It was a member of the Trematochampsidae, an enigmatic family of mesoeucrocodylians. Fossils have been found from the La Amarga Formation in Argentina and date back to the Barremian and Aptian stages of the Early Cretaceous. Amargasuchus inhabited a terrestrial paleoenvironment that existed during the Early Cretaceous in the Neuquén basin that was characterized by a system of braided rivers, lakes, and alluvial plains. Sauropod, abelisauroid, and stegosaurian dinosaurs have also been found existing in the Neuquén basin at this time.

The holotype was discovered in 1984 in association with the dicraeosaurid sauropod dinosaur Amargasaurus'.

Caypullisaurus

Caypullisaurus is an extinct genus of large platypterygiine ophthalmosaurid ichthyosaur from the Late Jurassic to the Early Cretaceous (Tithonian and Berriasian stages) of Argentina. Its holotype was collected from the Vaca Muerta Formation of Cerro Lotena, Neuquen, dating to the early Tithonian stage of the Late Jurassic, about 150 million years ago. Caypullisaurus was first named by Marta Fernández in 1997 and the type species is Caypullisaurus bonapartei. It is a member of the family Ophthalmosauridae, and closely related to Platypterygius and Brachypterygius. In 2012, Caypullisaurus was found to be most closely related to Athabascasaurus and "Platypterygius" australis, and to nest within the subfamily Platypterygiinae.

Chacaicosaurus

Chacaicosaurus is an extinct genus of long-snouted thunnosaur ichthyosaur known from the northwestern Patagonia area of Argentina.

Collón Curá Formation

The Collón Curá Formation (Spanish: Formación Collón Curá) is a Middle Miocene fossiliferous geological formation of the southern Neuquén Basin in northwestern Patagonia and the western Cañadón Asfalto Basin of central Patagonia, Argentina. The formation crops out from the southern Neuquén Province, the western Río Negro Province to the northern Chubut Province.

The formation, with a maximum thickness of 300 metres (980 ft), comprises tuffs and sandstones with minor siltstones, marls and limestones, deposited in a fluvial, deltaic and shallow to deep lacustrine environment in small basins separated by faults. The formation dates from the Langhian to earliest Tortonian epochs of the Middle to Late Miocene, typically Colloncuran.

The Collón Curá Formation is named after the Collón Curá River, a tributary of the Limay River in the Río Negro watershed, and lends its name to the Colloncuran, one of the South American land mammal ages. The formation has provided many fossils of mammals, reptiles, among others the snake Waincophis australis, and the largest terror bird Kelenken guillermoi. The rodent Galileomys colloncurensis and the typothere Protypotherium colloncurensis were named after the formation.

Comahuesaurus

Comahuesaurus is a genus of sauropod dinosaur of the family Rebbachisauridae. It was found in the Lohan Cura Formation, in Argentina and lived during the Early Cretaceous, Aptian to Albian. The type species is C. windhauseni, named by Carballido and colleagues in 2012. It had originally been assigned to Limaysaurus by Salgado et al. (2004), but was later assigned its own genus based on the presence of diagnostic characters in the caudal centra, pubis and ischium.Comahuesaurus is known from abundant material compared to other rebbachisaurids; 37 caudal vertebrae, three fragmentary dorsal vertebrae and multiple appendicular elements, including a right humerus, pubis, ischium and a 113 cm long left femur. In their phylogenetic analysis, Carballido et al. (2012) placed Comahuesaurus in an intermediate position between basal rebbachisaurids such as Histriasaurus and the derived clade formed by subfamilies Rebbachisaurinae and Limaysaurinae.It shares with more derived rebbachisaurids a reduced hyposphene-hypantrum system, but hadn't yet completely lost said structure; that change would happen at some further point in the evolution of the clade, as it is so far only known to be fully absent in limaysaurines.

Herbstosaurus

Herbstosaurus is the name given to a genus of pterosaurs that lived during the Late Jurassic period, in what is now Argentina. In 1969 Argentine paleobotanist Rafael Herbst in the province Neuquén at Picun Leufú dug up a piece of sandstone holding a number of disarticulated bones of a small reptile. At the time it was assumed the rock dated to the Middle Jurassic (Callovian), about 163 million years ago.

In 1974/1975 paleontologist Rodolfo Magín Casamiquela named the find as a new genus. The type species is Herbstosaurus pigmaeus. The genus name honours Herbst and connects his name to Greek sauros, "lizard", a usual element in the name of dinosaurs — Casamiquela assumed the new genus was a theropod dinosaur. The specific name is derived from Greek pygmaios, "dwarf": it was thought the form presented a small Compsognathus-like coelurosaurian belonging to the Coeluridae and one of the smallest dinosaurs then known.

Huincul Fault

The Huincul Fault or Huincul Fault Zone (Spanish: Falla de Huincul, Zona de falla Huincul) is an east-to-west-oriented, continental-scale fault that extends from the Neuquén Basin eastwards into the Argentine Shelf. To the west, it has been proposed to extend across the Andes to the Chilean Coast Range.In the Neuquén Basin, the fault exhibits a slightly curved path, being convex to the north. It is a major geological discontinuity and it truncates the north-to-south-oriented Pampean orogen, among other structures. Because of this, it has been proposed to represent the northern geological limit of Patagonia.

Isaberrysaura

Isaberrysaura is a genus of ornithischian dinosaur from the Early Jurassic Los Molles Formation of Patagonia, Argentina. The genus contains a single species, I. mollensis, described by Salgado et al. in 2017 from a single specimen. Although initially classified as a basal neornithischian, subsequent analysis has allied it with the Stegosauria; the morphology of its skull resembles those of other members of the group.

Lavocatisaurus

Lavocatisaurus is a genus of sauropod in the family Rebbachisauridae from the Early Cretaceous (Aptian to Albian) Rayoso Formation of the Neuquén Basin, northern Patagonia, Argentina.

Leinkupal

Leinkupal is a genus of diplodocine sauropod known from the Early Cretaceous (Late Berriasian to Early Valanginian stage) of the Bajada Colorada Formation, southeastern Neuquén Basin in the Neuquén Province of Argentina. It contains a single species, Leinkupal laticauda.

Mendozasaurus

Mendozasaurus is a genus of sauropod dinosaur. It was a member of Titanosauria, which were massive sauropods that were common on the southern landmasses during the Cretaceous period. The titanosaurian sauropod dinosaur Mendozasaurus neguyelap is represented by several partial skeletons from a single locality within the Coniacian (lower Upper Cretaceous) Sierra Barrosa Formation in the south of Mendoza Province, northern Neuquén Basin, Argentina.

The type species, Mendozasaurus neguyelap, was described by Argentine paleontologist Bernardo Javier González Riga in 2003. Mendozasaurus is the first dinosaur named from Mendoza Province, Argentina.

Mollesaurus

Mollesaurus is an extinct genus of large ophthalmosaurine ophthalmosaurid ichthyosaur known from northwestern Patagonia of Argentina.

Nacientes del Biobío Formation

Nacientes del Biobío Formation (Spanish: Formación Nacientes del Biobío) is a geological formation that crops out near the uppermost reaches of Bío Bío River, in south-central Chile, and nearby areas of Argentina. The formation is made up of basalt and pyroclastic rocks and marine sedimentary rocks, such as sandstone and mudstone. Some less abundant sedimentary lithologies are conglomerate, volcaniclastic sedimentary rock. The formation is intruded by Grupo Plutónico Galletué which is of Late Jurassic to Late Cretaceous age. Further north in Chile the formation is similar to Nacientes del Teno Formation while in Argentina it is similar to Los Molles Formation and Lotena Formation.

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.

Notocolossus

Notocolossus is a genus of herbivorous lithostrotian titanosaur sauropod dinosaur from late Cretaceous strata of Mendoza Province, Argentina.

Petrobrasaurus

Petrobrasaurus is a genus of herbivorous sauropod dinosaur. It is a titanosaur which lived during the upper Cretaceous period (Santonian age) in what is now Rincón de los Sauces, Patagonia, Argentina. It is known from the holotype MAU-Pv-PH-449 — a partial disarticulated skeleton recovered from the Plottier Formation (Neuquén Basin), Argentina. This genus was named by Leonardo S. Filippi, José Ignacio Canudo, Leonardo J. Salgado, Alberto C. Garrido, Rodolfo A. Garcia, Ignacio A. Cerda and Alejandro Otero in 2011, and the type species is Petrobrasaurus puestohernandezi. The generic name is derived from "Petrobras" (oil company) and saurus, "lizard". The specific name refers to the Puesto Hernández oil field, where the fossil remains were found.

Purranisaurus

Purranisaurus is an extinct genus of marine crocodyliform from the Middle to Late Jurassic period of Chile and Argentina. Rusconi originally regarded Purranisaurus potens (the type species) to be a plesiosaur; however, Gasparini demonstrated that it was in fact a metriorhynchid crocodyliform, and that may be a junior synonym of Metriorhynchus.

Zapalasaurus

Zapalasaurus is a genus of dinosaur described by Leonardo Salgado, Ismar de Souza Carvalho and Alberto C. It was named after the city of Zapala. The type species, Zapalasaurus bonapartei, was found in the La Amarga Formation of the Neuquén Basin, Neuquén Province, Argentina. It was a diplodocoid, a long-necked herbivore, and it lived during the Early Cretaceous. The authors conclude from examining the skeleton that "The record of Zapalasaurus bonapartei shows that, at least in the Neuquén Basin, basal diplodocoids were more diverse than previously thought." Zapalasaurus is assumed to have a long neck which would have been developed for feeding adaption, allowing its neck to swing in an arc like shape. This would allow Zapalasaurus to browse a wide variety of plants and greens without having to walk very far.

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