The Golfo San Jorge Basin (Spanish: Cuenca del Golfo San Jorge) is a hydrocarbon-rich sedimentary basin located in eastern Patagonia, Argentina. The basin covers the entire San Jorge Gulf and an inland area west of it, having one half located in Santa Cruz Province and the other in Chubut Province. The northern boundary of the basin is the North Patagonian Massif while the Deseado Massif forms the southern boundary of the basin. The basin has largely developed under condition of extensional tectonics, including rifting.[1]

Golfo San Jorge Basin
Cuenca del Golfo San Jorge
Oil well near the port city of Comodoro Rivadavia
Map showing the location of Golfo San Jorge Basin
Map showing the location of Golfo San Jorge Basin
Location of the basin in Argentina
Coordinates45°00′S 67°50′W / 45.000°S 67.833°W / -45.000; -67.833
EtymologySan Jorge Gulf
LocationSouthern South America
RegionPatagonia
Country Argentina
State(s)Chubut, Santa Cruz
CitiesComodoro Rivadavia
Characteristics
On/OffshoreBoth
BoundariesNorth Patagonian Massif, Deseado Massif, Andes
Part ofSouthern Atlantic rift basins
Area170,000 km2 (66,000 sq mi)
Hydrology
Sea(s)South Atlantic
River(s)Chico River
Lake(s)Lake Musters and Lake Colhué Huapí
Geology
Basin typeRift
PlateSouth American
OrogenyOpening of the South Atlantic
AgeEarly Jurassic-Pleistocene
StratigraphyStratigraphy
Field(s)Cañadón León, Cerro Dragón, Diadema, El Tordillo
Photograph of the first oil well in Comodoro Rivadavia

The basin is of paleontological significance as it hosts six out of 22 defining formations for the SALMA classification, the geochronology for the Cenozoic used in South America.

At the center of the basin accumulated sediments reach more than 8,000 metres (26,000 ft) of thickness. Oil was first discovered in 1907 and over the years it has become the second most productive hydrocarbon basin in Argentina after Neuquén Basin.[1]

Stratigraphy edit

The stratigraphy of the Golfo San Jorge Basin covers the following units:[1][2][3]

Unit Age
bold is SALMA type
Tectonic regime Depositional environment Thickness
(m)
Petroleum geology
Tehuelche Shingle Pleistocene Glacio-fluvial 40
Río Mayo Mayoan
Santa Cruz Santacrucian Fluvio-deltaic 200
Patagonia Shallow marine 280
Sarmiento
 Colhué Huapí Mb.
Chenque
Colhuehuapian Fluvio-lacustrine 120
Deseadan
Tinguirirican
Río Chico Koluel Kaike Divisaderan Lacustrine 42
Mustersan
Casamayor
Las Flores
Casamayoran Fluvio-lacustrine 44
Peñas Coloradas Riochican Fluvial 42
Itaboraian
Las Violetas Peligran 25
Salamanca Peligran Shallow marine-deltaic-fluvial 200 Petroleum reservoir
Tiupampan
Lago Colhué Huapí Maastrichtian
Campanian
Fluvial
Yacimiento El Trébol
Meseta Espinosa
Bajo Barreal
Laguna Palacios
Santonian
Aptian
Late sag Deltaic
Fluvio-lacustrine
4000+
Cañadón Seco
Comodoro Rivadavia
Bajo Barreal
Alluvial-fluvial-lacustrine
Mina El Carmen
Castillo
Fluvio-lacustrine
Pozo D-129
Matasiete
Early sag 1500+ Source rock and petroleum reservoir
Pozo Cerro Guadal Neocomian Late rift Fluvio-lacustrine 560
Pozo Anticlinal Aguada Bandera Lacustrine 1700+ Source rock
Bahía Laura
Lonco Trapial
Cerro Carnerero Mid-Late Jurassic Early rift Volcaniclastic 1300+
Early Jurassic Pre-rift Shallow marine 700+
Basement Paleozoic

See also edit

References edit

  1. ^ a b c Sylwan, Caudio A. (2001). "Geology of the Golfo San Jorge Basin, Argentina". Journal of Iberian Geology. 27: 123–157. Retrieved 4 December 2015.
  2. ^ Raigemborn et al., 2010, p.243
  3. ^ Cortés, 1986, p.49

Bibliography edit

General
Cretaceous

Paleogene edit

Andesitas Huancache Formation
Bororó Formation
Casamayor Formation
Las Flores Formation
Koluel Kaike Formation
Peñas Coloradas Formation
Río Chico Group
Salamanca Formation

Neogene edit

Río Mayo Formation
Sarmiento Formation & Colhué Huapí Member

Further reading edit