Correlations of some Neoproterozoic carbonate-dominated successions in South America based on high-resolution chemostratigraphy

Abstract

This report reviews and incorporates new elemental and isotope chemostratigraphic data for correlation of Neoproterozoic carbonate-dominated successions in South America (Argentina, Bolivia, Brazil, Paraguay and Uruguay). These thick mixed carbonate/siliciclastic successions were largely deposited in epicontinental basins or accumulated on passive margins on the edges of cratons (e.g. São Francisco, Amazonia, Rio Apa Block, Pampia and Río de la Plata paleocontinents) during extensional events related to the rifting of the Rodinia Supercontinent. From the stratigraphic point of view, these successions occur as three mega-sequences: glaciogenic, marine carbonate platform (above glaciomarine diamictites or rift successions), and dominantly continental to transitional siliciclastics. In the orogenic belts surrounding cratons, carbonate-dominated successions with important volcanoclastic/siliciclastic contribution have been, in most cases, strongly deformed. The precise ages of these successions remain a matter of debate, but recently new paleontological and geochronological data have considerably constrained depositional intervals. Here, we report high-resolution C, O, Sr, and S isotope trends measured in well-preserved sample sets and mainly use Sr and C isotopes RESUMO: Esta revisão incorpora novos dados isotópicos e quími-cos para correlação quimioestratigráfica de sucessões

Sedimentology and stratigraphy of Neoproterozoic-lower Paleozoic carbonate-siliciclastic succession of the southwesternmost Amazon Craton, state of Rondônia, Brazil

“…In addition, the δ 13 C of the Espigão d'Oeste cap dolostones exhibits typically negative values around -4 ‰ and -2 ‰ (Dardenne et al 2005, Afonso 2016, Gaia et al 2017. These values are comparable with δ 13 C profiles of post-late Cryogenian units of Southern Paraguay Belt (Nogueira et al 2007, Alvarenga et al 2008, Sial et al 2016) and other cap carbonates formed after Marinoan glaciation (Kennedy 1996, James et al 2001, Hoffman & Schrag 2002, Halverson et al 2010.…”

Extração Automática de Lineamentos na Exploração de Água Subterrânea: Caso dos Aquíferos Metassedimentares da Chapada Diamantina Centro-Setentrional

“…Sobrejacente têm-se o Grupo Chapada Diamantina com unidades metassedimentares mesoperoterozoicas representadas por conglomerados, arenitos e pelitos da Formação Tombador depositados em sistemas de leques aluviais e de rios entrelaçados, por vezes retrabalhados pelo vento e siltitos, arenitos e pelitos intercalados com laminitos algais, calcarenitos e estromatólitos colunares subordinados da Formação Caboclo, depositados em ambientes transicionais a marinho de águas rasas com períodos de exposição subaérea e ação de tempestades. Unidades meso-neoproterozoicas caracterizados por conglomerados basais sobrepostos a arenitos finos e raras intercalações pelíticas sedimentados em sistemas fluvioestuarinos com depósitos inter a submaré (Battilani, Gomes & Guerra 1997;Rocha 2003) e unidades neoproterozoicas do Grupo Una representado por diamictitos, arenitos e lamitos com dropstones da Formação Bebedouro depositados em um ambiente glaciomarino (Karfunkel & Hoppe 1988;Guimarães 1996;Figueiredo et al 2009) e calcissiltitos, calcarenitos e laminitos algais marinhos da Formação Salitre em condições sub, inter e supramaré (Figura 1A) (Misi & Veizer 1998;Sial et al 2016).…”

GOLD PROVENANCE AND CHARACTERIZATION USING MICRO X-Ray FLUORESCENCE (ΜXRF): PRELIMINARY RESULTS/ PROVENIÊNCIA E CARACTERIZAÇÃO DE OURO COM MICRO FLUORESCÊNCIA DE RAIOS X (ΜXRF): RESULTADOS PRELIMINARES

“…The mining areas are located in the hinge and NW flank zones of the Bento Gomes Anticlinal. Figure 1 presents a simplified geological map of the Paraguay Belt as presented by Sial et al (2016) Between 1982 and 1995, when a more effective control of the gold production by the municipality took place, this province produced about 26 tons of gold (official data). The data also show that the production peak occurred between 1990 and 1993, reaching 16.3 tons of gold.…”

“…The mineralization of the Santa Helena deposit is related to ounces of gold (production to date more reserves; Sillitoe, 2008). Sial et al, 2016).…”