Salta Basin or Salta Rift Basin is a
sedimentary basin
Sedimentary basins are region-scale depressions of the Earth's crust where subsidence has occurred and a thick sequence of sediments have accumulated to form a large three-dimensional body of sedimentary rock. They form when long-term subsidence ...
located in the
Argentine Northwest
The Argentine Northwest (''Noroeste Argentino'') is a geographic and historical region of Argentina composed of the provinces of Catamarca, Jujuy, La Rioja, Salta, Santiago del Estero and Tucumán.
Geography
The Argentine Northwest comprises v ...
.
[ The basin started to accumulate sediments in the ]Early Cretaceous
The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma.
Geology
Pro ...
(Neocomian
In geology, Neocomian was a name given to the lowest stage of the Cretaceous system. It is generally considered to encompass the interval now covered by the Berriasian, Valanginian and Hauterivian, from approximately 145 to 130 Ma. It was introduce ...
) and at present it has sedimentary deposits reaching thicknesses of . The basin contains seven sub-basins: Tres Cruces, Lomas de Olmedo, Metán, Alemanía, Salfity, El Rey, Sey and Brealito. The basin environment has variously been described as a " foreland rift
In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics.
Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-grabe ...
" and an "intra-continental rift". The basin developed under conditions of extensional tectonics
Extensional tectonics is concerned with the structures formed by, and the tectonic processes associated with, the stretching of a planetary body's crust or lithosphere.
Deformation styles
The types of structure and the geometries formed depend on ...
and rift-associated volcanism
Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called ...
.[
]
Description
The basin basement is composed of rocks belonging to the Puncoviscana Formation
Puncoviscana Formation ( es, Formación Puncoviscana) is a formation of sedimentary and metasedimentary rocks Late Ediacaran and Lower Cambrian age, estimated at between 700 and 535 Ma, that crop out in the Argentine Northwest. Most of the formati ...
.[Grier et al., 1991] The volcanism that began in the Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987.
In European lithostratigraphy, the name ...
was initially of subalkaline character (low sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable iso ...
and potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosphe ...
content), but turned increasingly alkaline in the Early Cretaceous.[Marquillas et al., 2005]
The rifts of Salta Basin developed in a time of generalized extensional tectonics
Extensional tectonics is concerned with the structures formed by, and the tectonic processes associated with, the stretching of a planetary body's crust or lithosphere.
Deformation styles
The types of structure and the geometries formed depend on ...
along western South America.[Ramos, 2009] It has been proposed that the Salar de Atacama
Salar de Atacama is the largest salt flat in Chile. It is located south of San Pedro de Atacama, is surrounded by mountains, and has no drainage outlets. In the east it is enclosed by the main chain of the Andes, while to the west lies a secondar ...
depression in Chile was once a westward rift arm of the Salta Basin.[Reutter et al., 2006]
Stratigraphy
References
Bibliography
;General
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;Guanaco Sonso Formation
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;Lumbrera Formation
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;Maíz Gordo Formation
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;Mealla Formation
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;Palo Pintado Formation
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;Piquete Formation
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;Quebrada de Los Colorados Formation
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Further reading
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{{Sedimentary basins of Argentina
Foreland basins
Mesozoic rifts and grabens
Sedimentary basins of Argentina
Sedimentary basins of Bolivia
Sedimentary basins of Chile
Geology of Antofagasta Region
Geology of Jujuy Province
Geography of Potosí Department
Geology of Salta Province
Geology of Tucumán Province