Changes

Parana-Etendeka Continental Basaltic Province represents one of the major volcanic events on Earth’s history. Is characterized by a fissural volcanism that occurred in the Early Cretaceous before the Gondwana rift and opening of South Atlantic Ocean. About 90% of the vulcanism is found in South America, covering 1,200,000 km² over the Parana Basin (Parana Continental Basaltic Province). The other 10% are in Etendeka (Etendeka Continental Basaltic Province), and Angola, Africa ([[:file:Parana-Etendeka_1.jpg|Figure 1]]).

Parana-Etendeka Continental Basaltic Province represents one of the major volcanic events on Earth’s history. It's characterized by a fissural volcanism that occurred in the Early Cretaceous before the Gondwana rift and opening of South Atlantic Ocean. About 90% of the volcanism is found in South America, covering 1,200,000 km² over the Parana Basin (Parana Continental Basaltic Province). The other 10% are in Etendeka (Etendeka Continental Basaltic Province), and Angola, Africa ([[:file:Parana-Etendeka_1.jpg|Figure 1]]).

[[file:Parana-Etendeka_1.jpg|thumb|Figure 1. Location of the Parana-Etendeka CBP]]

[[file:Parana-Etendeka_1.jpg|thumb|Figure 1. Location of the Parana-Etendeka CBP (modified from Jerram, 2002<ref name=Jerram_2002>Jerram, D.A., 2002. Volcanology and Facies architecture of flood basalts. Geological Society of America, Special paper. In: Menzies, M.A., Klemperer, S.L., Ebinger, C.J., Baker, J. (Eds.), Magmatic Rifted Margins: Geological Society of America Special Paper, vol. 362, pp. 119e132.</ref>]]

The Parana Continental Basaltic Province covers an area of 917.000 km² and has a volume of 600,000 km³.  It is composed mostly (90% of volume) by basaltic and andesitic basalts rocks with a tholeiitic affinity. Acidic rocks occur locally in the upper volcanic pile. Chemically the basalts were divided in two groups based in the TiO2 contents: The first group occurs dominantly in southern areas and has TiO2 lower than 2 wt. %, the second group has high TiO2 (>2%) and is dominant in the northern portion of the Parana Basin. These two groups of basaltic rocks were sub-divided in six magma types:  Gramado, Esmeralda and Urubici (Ti/Y<300) in the south, and Pitanga, Paranapanema and Ribeira (Ti/Y>300) in the northern magmas.  

The Parana Continental Basaltic Province covers an area of 917.000 km² and has a volume of 450,000 km³ (Frank et al., 2009)<ref name=Frank_2009>Frank, H.T., Gomes, M.E.B., Formoso, M.L.L., 2009. Review of the areal extent and the volume of the Serra Geral Formation, Parana Basin, South America. Pesquisa em Geociências 36, 49e57.

</ref>.  It is composed mostly (90% of volume) by basaltic and andesitic basalts rocks with a tholeiitic affinity. Acidic rocks occur locally in the upper volcanic pile. Chemically the basalts were divided in two groups based in the TiO2 contents: The first group occurs dominantly in southern areas and has TiO2 lower than 2 wt.%, the second group has high TiO2 (>2%) and is dominant in the northern portion of the Parana Basin (Bellieni et al., 1984<ref name=Bellieni_1984>Bellieni, G., Comin-Chiaramonti, P., Marques, L.S., Melfi, A.J., Picirillo, E.M., Nardy, A.J.R., Roisenberg, A., 1984. High- and Low Ti flood basalts from the Paran_a plateau (Brazil): petrogenetic and geochemical aspects bearing on their mantle origin. Neues Jahrb. für Mineral. Abh. 150, 272e306.</ref>; Mantovani et al., 1985<ref name=Mantovani_1985>Mantovani, M.S.M., Marques, L.S., De Sousa, M.A., Civetta, L., Atalla, L., Innocenti, F., 1985. Trace element and strontium isotope constraints on the origin and evolution of Paran_a continental flood basalts of Santa Catarina State, southern Brazil. J. Petrol. 26, 187e209.</ref>). These two groups of basaltic rocks were sub-divided in six magma types (Peate et al., 1992)<ref name=Peate_1992>Peate, D.W., Hawkeswort, C.J., Mantovani, M.S.M., 1992. Chemical stratigraphy of the Paran_a lavas (South America): classification of magma types and their spatial distribution. Bull. Volcanol. 55, 119e139.</ref>:  Gramado, Esmeralda and Urubici (Ti/Y<300) in the south, and Pitanga, Paranapanema and Ribeira (Ti/Y>300) in the northern magmas.  

Acidic rocks are characterized by high crystallization temperatures. In the Paraná Basin, temperatures obtained by the coexisting pyroxenes method are 1,030 ± 38ºC. Chemcally the acidic rocks are also divided in two groups: 1) Palmas type, dacitic and rhyolitic rocks with low TiO2 and low contents of incompatible elements,  dominant in the south of Parana Basin and is sub-divided in 5 sub-groups based on chemical characteristics: Caxias do Sul, Santa Maria, Anita Garibaldi, Clevelandia and Jacui. 2) Chapeco Type, porphyritic trachytes with high-TiO2, Ba, P, Zr and Sr. Present in the north and middle portions of the basin and is sub-divided in 3 sub-groups: Ourinhos, Guarapuava and Tamanara.

Acidic rocks are characterized by high crystallization temperatures. In the Paraná Basin, temperatures obtained by the coexisting pyroxenes method are 1,030 ± 38ºC (Bellieni et al., 1984)<ref name=Bellieni_1984 />. Chemically the acidic rocks are also divided in two groups (Bellieni et al. 1986<ref name=Bellieni_1984 />; Peate, 1997<ref name=Peate_1997>Peate, D.W., 1997. The Parana-Etendeka province. In: Mahoney, J.J., Coffin, M. (Eds.), Large Igneous Provinces: Continental, Oceanic, and Planetary Volcanism: Geophysical Monograph Series, vol. 100. American Geophysical Union, pp. 217e245.</ref>): 1) Palmas type, dacitic and rhyolitic rocks with low TiO2 and low contents of incompatible elements,  dominant in the south of Parana Basin and is sub-divided in 5 sub-groups based on chemical characteristics (Peate et al. 1992<ref name=Peate_1992 />; Nardy et al. 2008<ref name=Nardy_2008>Nardy A.J.R., Machado F.B., Oliveira M.A.F. 2008. As rochas vulcânicas mesozoicas ácidas da Bacia do Paraná: litoestratigrafia e considerações geoquímicas-estratigráficas. Revista Brasileira de Geociências, 38(1):178-195.</ref>): Caxias do Sul, Santa Maria, Anita Garibaldi, Clevelandia and Jacui. 2) Chapeco Type, porphyritic trachytes with high-TiO2, Ba, P, Zr and Sr. Present in the north and middle portions of the basin and is sub-divided in 3 sub-groups: Ourinhos, Guarapuava (Peate 1997)<ref name=Peate_1997 /> and Tamanara (Nardy et al. 2008)<ref name=Nardy_2008 />.

 

 

 

Furthermore, studies based in the morphology of different magma types and the facies architecture (Lima et al., 2012<ref name=Lima_2012>Lima, E.F., Waichel, B.L., Rossetti, L.M.M., Viana, A.R., Scherer, C.M., Bueno, G.V., Dutra, G., 2012. Morphological and petrographic patterns of the pahoehoe and 0a0_a flows of the Serra Geral Formation in the Torres Syncline.</ref>; Waichel et al., 2012<ref name=Waichel_2012>Waichel, B.L., Lima, E.F., Viana, A.R., Scherer, C.M., Bueno, G.V., Dutra, G., 2012. Stratigraphy and volcanic facies architecture of the Torres Syncline, Southern Brazil, and its role in understanding the Paran_a-Etendeka Continental Flood Basalt Province. J. Volcanol. Geotherm. Res. 216, 74e82.</ref>; Rossetti et al.,2014<ref name=Rossetti_2014>Rossetti, L.M., Lima, E.F., Waichel, B.L., Scherer, C.M., Barreto, C.J., 2014. Stratigraphical framework of basaltic lavas in Torres Syncline Main Valley, Southern Brazil. Journal of South American Earth Sciences 56 (2014) 409-421 </ref>) has helped the understanding the paleotopography, emplacement and volumetric flow rate of Parana Etendeka volcanism.