The Paraná Basin stretches from the Brazilian state of
Mato Grosso in the north to northern Argentina and Uruguay in the south. The southern portion in Uruguay is locally known as Norte Basin.
Pioneer studies (1908). The first study on the Brazilian side of the Paraná Basin dates from 1841, when a
Brazilian Imperial Government Mission prospected for
coal. Turning point in the basin's geological understanding was the "White Report", published in 1908 by the American
geologist Israel C. White, head of the "Comissão de Estudos das Minas de Carvão de Pedra do Brasil" (Commission for Studies on Brazilian Coal Mines). One of the main results of these studies, besides the reconnaissance for coal, was the discovery of
Mesosaurus fossils within
Permian black
shales (
Irati Formation), and the
Glossopteris flora within the
Permian coals. White was one of the first to propose the equivalence between the
South American Permian strata and similar rocks of the
Karoo Basin in
South Africa.
Basin evolution The basin developed during the
Paleozoic and the
Mesozoic with a
sedimentary record comprising
rocks from the
Ordovician right up to the
Cretaceous, thus spanning the time interval between 460 and 66 million years. The maximum thickness of the infill reaches in its central area and is composed of sedimentary and
igneous rocks. The sedimentary cover extends across various Precambrian geologic provinces: the
Río de la Plata Craton, the
Mantiqueira Province, the
Luis Alves craton fragment, the
Tocantins Province and the
Paranapanema block. This last province is distinct in that it is wholly covered by basin sediments and therefore poorly known. The Paraná Basin is a typical
intra-cratonic flexural basin, although during the Paleozoic it was a
gulf that opened to the southwest. The basin genesis is related to the
convergence between the former
Gondwana supercontinent and the
oceanic crust of the former
Panthalassa ocean. The basin formed, at least during the Paleozoic
Gondwanide orogeny, as a
foreland basin. In the
Permian and
Triassic the area between Asunción and Río Grande was uplifted in connection to the Gondwanide orogeny effectively splitting the basin in the two. The piling up of material in Bolivia and the
Argentine Northwest during the
Andean orogeny caused the
Asunción arch, a
forebulge, to develop in Paraguay. The Asunción arch makes up the modern western boundary of Paraná Basin.
Stratigraphy The sedimentary column of the Paraná Basin was divided by Milani in 1997, into six second order
allostratigraphic supersequences (in the sense of Vail, 1977). These sequences define the
stratigraphic framework of the basin and are bound by distinct depositional hiati, caused by
erosive events. ;Neogene cover In the Argentinian part of the basin, the Serra Geral Formation is overlain by the
Huayquerian Ituzaingó Formation that underlies the
Pleistocene Toropí and
Yupoí Formations. Older Neogene formations in the basin comprise the Late Miocene
Paraná Formation. The Uruguayan part of the basin contains the
Late Pleistocene (
Lujanian)
Dolores and
Sopas Formations and the Brazilian portion hosts the Lujanian
Touro Passo Formation.
Natural resources The main
natural resources
extracted in Paraná Basin are
groundwater,
coal and
oil shale. ;Groundwater The Guaraní Aquifer is one of the world's largest
aquifer systems and an important source of
fresh water in
Argentina, Brazil,
Paraguay and
Uruguay. The lithology of the Aquifer consists mainly of highly
permeable sandstones of the Botucatu and Pirambóia formations. The aquifer covers with an estimated volume of about of water. ;Energy resources • Coal: The Brazilian coal resources are estimated at 32 billion
metric tons (32
Pg), classified as bituminous to sub-bituminous coal and are mainly associated with sandstones of the Rio Bonito Formation. The major producers are located in
Rio Grande do Sul and
Santa Catarina states and minor producers are located in
Paraná and
São Paulo states. • Natural gas: There is one
gas field in the Paraná Basin, the
Barra Bonita Field, located in Paraná state and discovered in 1996, with estimated reserves of about . • Oil shale: Since 1972
Petrobras extracts
hydrocarbons from the Irati Formation
oil shales in São Mateus do Sul, a city in the Brazilian state of
Paraná, using the
Petrosix process, a Petrobras
patent. The Irati Formation reserves are estimated at of oil, 9 million metric tons of
liquefied gas (LPG), of
shale gas and 18 million metric tons of
sulfur in the states of São Paulo, Paraná, Santa Catarina and Rio Grande do Sul. == See also ==