Formação Taciba: última manifestação glacial no Paraná

Mottin, Thammy Ellin; Vesely, Fernando Farias

doi:10.5380/geo.v78i0.79352

Cited by 4 publications

(1 citation statement)

References 35 publications

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“…In the Paraná Basin in south Brazil, the Taciba Formation (uppermost Itararé Group) is interpreted as a proximal glaciomarine unit yielding similar SSW sediment transport (Mottin et al, 2018), which is in contrast with the lower and middle Itararé Group and with the general view of S and SE glacial centers (Rosa et al, 2016). The Taciba Formation is early Permian (Asselian-Sakmarian age) based on palynomorphs (Souza and Marques-Toigo, 2003;Mottin et al, 2018) and invertebrates (Taboada et al, 2016), and represents the final deglacial sequence of the LPIA in the Paraná Basin (Mottin and Vesely, 2021). It records successive stages of ice retreat and advance culminating in base-level fall and the development of paleosol on diamictites below the post-glacial, coal-bearing Rio Bonito Formation (Mottin et al, 2018).…”

Section: Age Constraints and Glacial Dynamicsmentioning

confidence: 99%

Late Cryogenian and late Paleozoic ice ages on the São Francisco craton, east Brazil

Uhlein

Uhlein²

2022

Front. Earth Sci.

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The miniature paleocontinent in the region of the São Francisco River valley, in eastern Brazil, holds the record of two different glacial epochs. The late Cryogenian Jequitaí Formation from the Bambuí Group is up to 100 m thick and covers areas mainly in the central São Francisco craton. Evidences for glacial sedimentation are beautifully preserved E-W grooves and striations, dropstones within fine-grained rocks, and a full set of diamictites enclosing a rich and complex depositional history. The Jequitaí Formation is in close link with the tectonic evolution of the São Francisco paleocontinent and the West Gondwana amalgamation. From west, the precocious Paranapanema and São Francisco blocks collision in late Cryogenian flexured the foreland lithosphere and created depozones that were infilled by glacial sediments. Toward east, the rifting and opening of the Adamastor Ocean allowed thick glacial and non-glacial deposits to form through subaqueous gravitational sedimentation. From west to east, proximal and distal glaciomarine, glaciocontinental, and non-glacial resedimentation are identified and linked to the evolving continental masses and climate during the Cryogenian and beginning of Ediacaran. The late Paleozoic Santa Fé Group is the youngest record of glaciation on the São Francisco craton. It is 60–80 m thick and yields consistent and confident glacial evidences such as N-S striations on top of Cambrian sandstones, ice-rafted debris, and rain-out diamictite, all preserved in small and patchy areas in the west-central São Francisco craton. Paleocurrents suggest a northern ice center and sedimentary facies indicate deposition in continental lakes and rivers. Although late Paleozoic, its age is poorly constrained and likely correlated with the uppermost Itararé Group (Taciba Formation) of Paraná Basin in south Brazil. Deglaciation and strong isostatic adjustments make up the termination of the Santa Fé Group sedimentary record and depict a glaciocontinental system evolved on an interior stable continental crust. The late Neoproterozoic Jequitaí Formation and the late Paleozoic Santa Fé Group are parts of the earth’s sedimentary history preserving a rich record of climate, tectonic, and surface processes in part controlled by the evolving continental masses on the São Francisco craton.

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Section: Age Constraints and Glacial Dynamicsmentioning

confidence: 99%

Late Cryogenian and late Paleozoic ice ages on the São Francisco craton, east Brazil

Uhlein

Uhlein²

2022

Front. Earth Sci.

View full text Add to dashboard Cite

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Spatiotemporal variability of the late Paleozoic glacial-to-postglacial transition across eastern Paraná Basin, Brazil

Mottin

Vesely

Iannuzzi

et al. 2023

Sedimentary Geology

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A micromorphological perspective on the Neoproterozoic Smalfjord and Mortensnes Formation diamictites—Varangerfjord, Norway

Menzies

2023

Can. J. Earth Sci.

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Many Neoproterozoic diamictites are glacial in origin (Young, 2018). However, many are thought to be non-glacial mass movement deposits. Discussion on the nature of Neoproterozoic climate change focuses on the controversial origin of diamictite-bearing strata and the criteria to determine the extent and nature, or not, of glacial influence on their deposition. At the macroscale, sediments (diamictites) deposited beneath palaeo-ice masses or debris flows are massive, lack few visible signs of stratification or deformation signatures. Microscopic investigations have resulted in specific sedimentary structures being identified, indicative of stress during glacial deposition or developed in transit within mass movements. Case examples derived from the Neoproterozoic in Varanger, Norway have been investigated that provide strain signatures of ‘unique sequences’ of microstructures. Micromorphology, relatively new to Precambrian research, can deliver far greater detail on the depositional and deformation histories recorded by these diamictites than obtained from macroscale studies alone. The technique provides evidence of composite deformation histories of potential glacigenic and non-glacigenic sequences. Many microstructures can be observed in most diamictites. It can be demonstrated that diamictites, both glacigenic and non-glacigenic, contain most of these microstructures in varying levels of abundancy and can be separated on specific ‘sets’ of summative structures present. At Varanger 12 samples were analyzed for thin sectioning. As illustrative of the thin sections as whole, 6 are presented here that offer a microscale perspective on the diamictites from this area and establish that both the Smalfjord and Mortensnes Formation diamictites are of glacial terrestrial or subaqueous origin.

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Formação Taciba: última manifestação glacial no Paraná

Cited by 4 publications

References 35 publications

Late Cryogenian and late Paleozoic ice ages on the São Francisco craton, east Brazil

Late Cryogenian and late Paleozoic ice ages on the São Francisco craton, east Brazil

Spatiotemporal variability of the late Paleozoic glacial-to-postglacial transition across eastern Paraná Basin, Brazil

A micromorphological perspective on the Neoproterozoic Smalfjord and Mortensnes Formation diamictites—Varangerfjord, Norway

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