Talk:Parana Basin

From SEG Wiki
Jump to navigation Jump to search
ADVERTISEMENT

Introduction

The Paraná Basin, shown in Figure 1, is a large cratonic sedimentary basin situated in the central-eastern part of South America. About 75% of its areal distribution occurs in Brazil, from Mato Grosso to Rio Grande do Sul states. The Paraná Basin covers an area of about 1,500,000 km2 (580,000 sq mi).[1]

Figure 1 Satellite view of South America showing the Paraná basins.

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. The basin has an oval shape with the major axis N-S, its current boundary is defined by erosive limits related largely to the Mesozoic-Cenozoic tectonic history of the continent.[2]

Basin Evolution

Sediments were deposited in the Paraná Basin during the Paleozoic and the Mesozoic Era (450-65 Ma), keeping record of nearly 400 million years of Phanerozoic history of this region of the world. The basin accumulated siliciclastic, chemical and volcaniclastic sediments, between the Neo-Ordovician and Late Cretaceous. Part of the accumulation time a was interspersed with depositional gaps that separate the various super sequences.[3]

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 7,000 metres (23,000 ft) in its central area and is composed of sedimentary and igneous rocks.

Geological Setting

Seal

The Basin's primary seal system originates via a soft anticline. There is a contribution of a stratigraphic sandy channel in the lowermost portion of the package. It is also important to mention the unconventional role of the diabase sills sealing the structure.[4]

Source Rock & Migration

It is well reported that there are two main potential source-rock systems in the Paraná Basin: the middle to Upper Devonian black shales from the São Domingos Member of the Ponta Grossa Formation; and the middle Permian black bituminous shales and marls from the Irati Formation.[5]

Reservoir

There are 57 large reservoirs in the basin. The power plants of greatest installed capacity are Itaipu, Furnas and Porto Primavera. Its main tributaries are the rivers Grande, Paranaíba, Tietê, Paranapanema and Iguaçu. The growth of large urban centers, like São Paulo, Curitiba and Campinas, applies great pressure on the hydraulic resources.[6]

Trap

The only commercial accumulation system in the basin occurred in the Barra Bonita Field, where a gentle sill anticline acts as a trap caused by the igneous intrusions, although there is a contribution of a stratigraphic sandy channel in the lowermost portion of the package. Figure 2 shows what a subsurface view of these traps can look like.[7]

Figure 2 Examples of different trap types.

Natural Resources

The main natural resources extracted in Paraná Basin are groundwater, coal and oil shale. Common risks and uncertainties associated with the Basin are Population growth and inadequate use of land. These are challenges to the preservation of biodiversity and resources such as the much needed water in the area[8]

Groundwater

Most of the the groundwater from the Paraná Basin comes from the nearby source of the Guaraní Aquifer

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 496,000,000 m3 (1.75×1010 cu ft). The only current onshore field in the Paraná basin is the Barra Bonita
  • 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 700,000,000 bbl (110,000,000 m3) of oil, 9 million metric tons of liquefied gas (LPG), 25 cubic kilometers (8.8×1011 cu ft) of shale gas and 18 million metric tons of sulfur in the states of São Paulo, Paraná, Santa Catarina and Rio Grande do Sul.

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.

The stratigraphic record of the Paraná Basin comprises a sedimentary-magmatic package with a maximum total thickness of c.7000 meters. It is divided into six large scale units or supersequences, in the form of rock packages representing each temporal interval with tens of millions of years of duration and enveloped by surfaces of discordance of interregional character. These are the Rio Ivaí, Paraná, Gondwana I, Gondwana II, Gondwana III and Bauru.

Risks & Uncertainties

Most of the risks and uncertainties originate from a geological standpoint. The Basin itself is a main driver for the economic success of the surrounding areas. It plays a significant role in the Brazilian economy and development, greatly contributing to economic sectors, such as agriculture, livestock, energy, and urban and industrial water supply. Specifically, rapid population growth has affected the area greatly.[9] This has contributed to a significant increase in land usage. This have many affects on the basin as well as the water sources around it.

Tectonic History

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; an ancient supercontinent that incorporated present-day South America, Africa, Arabia, Madagascar, India, Australia, and Antarctica[10], and the oceanic crust of the former Panthalassa ocean.

Depositional Environment

Guaraní Aquifer

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 1,200,000 km2 (460,000 sq mi) with an estimated volume of about 37,000 km3 (3.0×1010 acre⋅ft) of water.[11]

References

↑ 1. Paraná River Basin: Itaipu Binacional. Paraná River Basin | ITAIPU BINACIONAL. (n.d.). Retrieved December 7, 2022, from https://www.itaipu.gov.br/en/energy/parana-river-basin

↑ 2. (PDF) Parana Basin - researchgate.net. History of the Paraná Basin. (n.d.). Retrieved December 8, 2022, from https://www.researchgate.net/publication/236359071_Parana_basin

↑ 3. Encyclopædia Britannica, inc. (n.d.). Gondwana. Encyclopædia Britannica. Retrieved December 7, 2022, from https://www.britannica.com/place/Gondwana-supercontinent

↑ 4. Paraná River, Basin and Delta (South America). Paraná River, Basin & Delta (South America) | LAC Geo. (n.d.). Retrieved December 7, 2022, from https://lacgeo.com/parana-river-basin-delta-south-america

↑ 5. Milani, E. J., Araujo, L. M., Cupertino, J. A., Faccini, U. F., & Scherer, C. M. (1998, July 1). Sequences and stratigraphic hierarchy of the Parana Basin (ordovician cretaceous), Southern Brazil. Boletim IG-USP. Serie Cientifica. Retrieved December 7, 2022, from https://www.osti.gov/etdeweb/biblio/20183601

↑ 6. Barros IT;Ceccon JP;Glinski A;Liebel S;Grötzner SR;Randi MAF;Benedito E;Ortolani-Machado CF;Filipak Neto F;de Oliveira Ribeiro CA; (n.d.). Environmental risk assessment in five rivers of Parana River basin, southern Brazil, through biomarkers in astyanax SPP. Environmental science and pollution research international. Retrieved December 7, 2022, from https://pubmed.ncbi.nlm.nih.gov/28540546/

↑ 7. Brazil: Brazil oil production bounces back as deepwater search broadens ... Brazil oil production bounces back as deepwater search broadens. (n.d.). Retrieved December 8, 2022, from https://www.offshore-mag.com/home/article/16758787/brazil-brazil-oil-production-bounces-back-as-deepwater-search-broadens

↑ 8. Paraná Basin: Solving the puzzles with Gas Geochemistry. Brazil Petroleum Studies. (2022, June 2). Retrieved December 7, 2022, from https://brazilpetrostudies.com.br/2022/06/02/parana-basin-solving-the-puzzles-with-gas-geochemistry/

↑ 9. Paraná River Basin: Itaipu Binacional. Paraná River Basin | ITAIPU BINACIONAL. (n.d.). Retrieved December 7, 2022, from https://www.itaipu.gov.br/en/energy/parana-river-basin

Important Papers

This section allows contributors to point to other important papers or books that have been written on the subject matter.

External Links

Paraná River Basin. https://www.itaipu.gov.br/en/energy/parana-river-basin

The Paraná-Paraguay Basin: Geology and Paleoenvironments. https://www.researchgate.net/publication

Gondwana, ancient supercontinent. https://www.britannica.com/place/Gondwana-supercontinent