Glacial diamictites of Serra Azul Formation (Ediacaran, Paraguay belt): Evidence of the Gaskiers glacial event in Brazil

Alvarenga, Carlos J. S.; Figueiredo, Milene Freitas; Babinski, Marly; Pinho, Francisco Egídio Cavalcante

doi:10.1016/j.jsames.2006.09.015

Cited by 66 publications

(54 citation statements)

References 19 publications

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“…More recently, Figueiredo (2006) and subsequently Alvarenga et al (2007) described a new unit, the Serra Azul Formation, in between carbonates of the Araras Group and the siliciclastics of the Alto Paraguay Group (Fig. 1B).…”

Section: Regional Settingmentioning

confidence: 97%

“…1B). The basal part of this formation is composed of a glaciogenic diamictite, containing multiply striated sandstone clasts (Alvarenga et al, 2007) and striated, polished, and bullet-shaped mudstone clasts (McGee et al, 2013), which is overlain by a transgressive package of interlayered silts and fi ne sands. The siltstone and sandstone of the upper Alto Paraguay Group were shed off rising topography-the Paraguay orogen-in response to collision of the Amazonian craton, the São Francisco craton, and the Paranapanema block between ca.…”

Section: Regional Settingmentioning

confidence: 99%

“…The depositional model proposed for these units is that of a passive margin environment from platformal to outer slope from west to east, respectively (Alvarenga and Trompette, 1992). This period of deposition was followed by a period of glaciation responsible for depositing the Serra Azul Formation in a glaciomarine environment inferred to be related to the Gaskiers glaciation (Alvarenga et al, 2007;McGee et al, 2013).…”

Section: Tectonic Model and The Paraguay Belt Within South America Anmentioning

confidence: 99%

“…Given that the Serra Azul Formation diamictite lies stratigraphically above a supposed Marinoan cap carbonate (Babinski et al, 2006;Nogueira et al, 2003), several authors have correlated the Serra Azul diamictite with the ca. 582 Ma Gaskiers glaciation (Alvarenga et al, 2007;McGee et al, 2013). The maximum depositional ages of the Raizama and Sepotuba Formations are constrained by the youngest analyzed grains at 635 Ma and 615 Ma, respectively.…”

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confidence: 99%

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Age and provenance of the Cryogenian to Cambrian passive margin to foreland basin sequence of the northern Paraguay Belt, Brazil

McGee

Collins

Trindade

et al. 2014

Geological Society of America Bulletin

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The Paraguay Belt in central South America developed in response to the collision of the Amazonian craton, the São Francisco craton, and the Paranapanema block. The alleged "Brasiliano" age (ca. 620 Ma) of orogenesis has recently been questioned by paleo magnetic and radioisotopic ages that indicate the closing stages of orogenesis occurred well into the Cambrian. We investigated the timing of deposition and source areas for these sedimentary rocks overlying the Amazonian craton using integrated U-Pb and Hf isotope data of detrital zircons from within this sequence. In total, 742 detrital zircon U-Pb ages were analyzed from samples taken from the base to the top of this sedimentary succession. Maximum depositional ages from the uppermost part of this sequence of rocks, the Diamantino Formation, indicate that fi nal deposition began no earlier than 560 ± 13 Ma and possibly as young as the Cambrian. Given that zircon inheritance in these rocks continues up until this age and that known Amazonian craton ages are older than ca. 950 Ma, we considered other potential sources for these sediments. This was achieved by integrating the U-Pb detrital zircon data with Hf isotopic data from these zircons that have ε Hf values ranging from -18 to 12. The ε Hf signature is consistent, with a predominantly Amazonian source until the early Neoproterozoic, at which point the signal becomes signifi cantly more evolved. These data, when combined with other evidence discussed here, are consistent with an ocean to the east of the present-day Amazonian craton that did not close until the latest Ediacaran-Cambrian.

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Section: Regional Settingmentioning

confidence: 97%

Section: Regional Settingmentioning

confidence: 99%

Section: Tectonic Model and The Paraguay Belt Within South America Anmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Age and provenance of the Cryogenian to Cambrian passive margin to foreland basin sequence of the northern Paraguay Belt, Brazil

McGee

Collins

Trindade

et al. 2014

Geological Society of America Bulletin

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show abstract

“…A sucessão completa só veio a ser identificada por Figueiredo et al (2004), que apontou evidências glaciais relacionadas aos diamictitos. Sua posição estratigráfica distinta, litologia característica e mapeabilidade na escala de 1:250.000 requer o estabelecimento de uma nova unidade estratigráfica, denominada Formação Serra Azul (Figueiredo et al, 2005;Alvarenga et al, 2007).…”

Section: Introductionunclassified