The Capiru Group: From passive margin to syn-orogenic units, implications for the evolution of the northern margin of the Curitiba microplate, Western Gondwana

Santos, Larissa da Rocha; Leandro, Renato; Fedalto, Guilherme; Spisila, André Luis; Bahniuk, Anelize; Siga, Oswaldo; Cury, Leonardo Fadel

doi:10.1016/j.jsames.2021.103555

Cited by 5 publications

(10 citation statements)

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“…The Capiru Group (Figure 1) is a 4-km-thick basin record deposited on the Northern margin of the Curitiba microplate-a continental segment F I G U R E 1 Geological context of the Capiru Group, southern Ribeira belt (Brasiliano -Pan-African), Brazil. (a) Simplified geology of the Capiru Group (adapted from Santos, Spisila, et al, 2021 andCaltabelotta et al, 2017) and location of the studied profiles. The XY coordinates of the sections can be consulted in Table 1.…”

Section: Geological Setting and Age Constraintsmentioning

confidence: 99%

“…The Pre-Morro Azul unconformity is interpreted as a regional disconformity (Santos, Leandro, et al, 2021) and considered to be Neoproterozoic in age (Santos et al, 2022), possibly related to the Marinoan glaciation (650-632,3 ± 5.9 Ma). This disconformity is similar to the Piedra Amarilla Surface, described in units deposited on the Río de la Plata craton margins (G omez-Peral et al, 2017(G omez-Peral et al, , 2021Poiré et al, 2018).…”

Section: Geological Setting and Age Constraintsmentioning

confidence: 99%

“…The group is composed of six formations (Figure 2), termed from oldest to youngest as Santana (siliciclastic proximal to distal marine shelf), Juruqui (siliciclastic proximal to distal deltaic), Rio Branco (carbonate platform), Morro Azul (carbonate lagoonal to shallow marine), Morro Grande (siliciclastic proximal to distal deltaic/marine) and Bocaina formations (siliciclastic estuarine to shallow marine); (Santos, Leandro, et al, 2021).…”

Section: Geological Setting and Age Constraintsmentioning

confidence: 99%

“…The Pre-Morro Azul disconformity was initially interpreted to be a sequence boundary that marks a basinward shift in facies as result of sea-level fall (Santos, Leandro, et al, 2021). On the cratonic domain, the weathering profiles related to this period are interpreted to be the source for the bauxitic materials deposited Dercourt, 1990;Khosravi et al, 2017;Kiaeshkevarian et al, 2020;Mindszenty et al, 1995;Stampfli et al, 2013).…”

Section: Spatial Distribution Of the Morro Azul Paleoweathering Surfa...mentioning

confidence: 99%

“…In the Capiru Group, southern Ribeira belt (Brazil), the recognition of regional unconformities in the stratigraphic record (Santos, Leandro, et al, 2021) coupled with the presence of high‐Al (meta‐) pelites (Faleiros, 2017; Santos, Leandro, et al, 2021; Vasconcellos & Nadalin, 1991) has brought insights regarding the nature of the sedimentary precursors (protoliths) of these Al‐rich rocks. One of the most reasonable explanations for the genesis of high‐Al (meta‐) pelites was the effect of leaching and consequent Al‐enrichments on weathered profiles developed above the Paleoproterozoic granite‐gneiss rocks that were later metamorphosed during the Brasiliano–Pan African orogenies (800–490 Ma).…”

Section: Introductionmentioning

confidence: 99%

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The formation and evolution of Al‐rich protoliths in the southern Ribeira belt, Brazil: Insights from remnants of a Precambrian paleoweathering surface

Santos,

Fedalto,

Bahniuk

et al. 2023

Earth Surf Processes Landf

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Bauxitic clays, clayey bauxites and bauxites are residual products formed from the weathering of aluminosilicate‐rich parent rocks under wet and warm conditions. These deposits show a complex interplay between remobilisation of pre‐existing kaolinitic soils and depositional micro‐environments.In the southern Ribeira belt, Brazil, a paleoweathering surface developed on the continental shelf of the Capiru Group passive margin strata and on its basement/source rocks. This weathering cycle gave rise to a paleosol profile on the continental domain and a karstic paleotopography on the emerged carbonate shelf. The surface and karstic nets were later caped and filled with Al‐rich materials, typical of remobilised soils, bauxitic clays, clayey bauxites and pods of karst‐type bauxites.The age of the disconformity is Pre‐Brazilian/Pan‐African, implying a Neoproterozoic age for the weathering surface. In this study, we investigate the relationship among disconformities, paleosols and karst topography to better understand the stratigraphic control, chemical composition and mineralogy of the Al‐rich materials. We interpret this horizon as the remnants of a (meta‐)paleoweathering surface that can serve as a valuable key bed for stratigraphic correlation and paleogeographic reconstructions.We propose that the triggering process for the genesis of the paleosol profiles, bauxitic material and bauxite pods was a coupled mechanism between favourable climate and uplift along the northern margin of the Curitiba–Angola craton, creating a karstic topography that allowed the down‐plain transport of Al‐rich materials. In a later stage, these deposits were metamorphosed, developing a series of Al silicates in unusual paragenesis, typical of Al‐rich protoliths.The presence of these paragenesis, along with the recognition of the disconformity–paleoweathering surface pair, could be a useful tool to understand the paleoenvironmental and paleogeographic evolution of highly deformed terrains.

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Section: Geological Setting and Age Constraintsmentioning

confidence: 99%