Glacial Environments

Netto, Renata Guimarães; Benner, Jacob S.; Buatois, Luís A.; Uchman, Alfred; Mángano, M. Gabriela; Ridge, John C.; Kazakauskas, Vaidotas; Gaigalas, Algirdas

doi:10.1016/b978-0-444-53813-0.00011-3

Cited by 23 publications

(15 citation statements)

References 53 publications

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“…On the other spectrum of the scale, the near-field effects (i.e. Large-scale events, such as the deglaciation that immediately followed the Gondwana Ice Age, undoubtedly have played a major role on coastal ecosystems, strongly affecting benthic communities (Buatois et al, 2006(Buatois et al, , 2010Netto et al, 2009Netto et al, , 2012. The present study bridges the gap between these two scales of analysis by showing that freshwater release was significant at a regional and inter-basin scale, with ablation of the Late Carboniferous-Early Permian ice cap affecting the Andean basins of Argentina.…”

Section: Discussionmentioning

confidence: 99%

Global deglaciation and the re‐appearance of microbial matground‐dominated ecosystems in the late Paleozoic of Gondwana

et al. 2013

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The extensive matgrounds in Carboniferous-Permian open-marine deposits of western Argentina constitute an anachronistic facies, because with the onset of penetrative bioturbation during the early Paleozoic microbial mats essentially disappeared from these settings. Abundant microbially induced sedimentary structures in the Argentinean deposits are coincident with the disappearance of trace and body fossils in the succession and with a landward facies shift indicative of transgressive conditions. Deposits of the Late Carboniferous-Early Permian glacial event are well developed in adjacent basins in eastern Argentina, Brazil, South Africa and Antarctica, but do not occur in the western Andean basins of Argentina. However, the deglaciation phase is indirectly recorded in the studied region by a rapid rise in sea level referred to as the Stephanian-Asselian transgression. We suggest that an unusual release of meltwater during the final deglaciation episode of the Gondwana Ice Age may have dramatically freshened peri-Gondwanan seas, impacting negatively on coastal and shallow-marine benthic faunas. Suppression of bioturbation was therefore conducive to a brief re-appearance of matground-dominated ecosystems, reminiscent of those in the precambrian. Bioturbation is essential for ecosystem performance and plays a major role in ocean and sediment geochemistry. Accordingly, the decimation of the mixed layer during deglaciation in the Gondwana basins may have altered ecosystem functioning and geochemical cycling.

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Section: Discussionmentioning

confidence: 99%

Global deglaciation and the re‐appearance of microbial matground‐dominated ecosystems in the late Paleozoic of Gondwana

et al. 2013

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“…Fjords are favorable environments to gravitational flows; they feature steep walls and high sedimentation rates (Syvitski et al, 1995). , 2002;Lermen, 2006;Buatois et al, 2006Buatois et al, , 2010Netto et al, 2009Netto et al, , 2012. Maculichna varia is abundant in the sediments of the Itararé Group throughout the Rio Grande do Sul state (Lermen, 2006).…”

Section: Diamictitementioning

confidence: 95%

Late Paleozoic paleofjord in the southernmost Parana Basin (Brazil): Geomorphology and sedimentary fill

et al. 2016

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“…The dominant facies F3 represents fallout of silt‐rich hemipelagic suspension, with the high degree of bioturbation and diversity of trace‐making organisms indicating a low‐energy fjord‐floor environment (Netto et al ., ). Scattered outsized clasts are ice‐rafted debris, transported by icebergs and shed from coastal ice‐foot floes ( cf .…”

Section: Lithofacies Associationsmentioning

confidence: 97%

Late Quaternary sedimentation and permafrost development in a Svalbard fjord‐valley, Norwegian high Arctic

et al. 2018

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The infilling history of the Adventdalen fjord‐valley in central Spitsbergen is reconstructed, with a focus on permafrost development, based on sedimentological and cryostratigraphic evidence from drilling cores. The techniques of optically stimulated luminescence and radiocarbon accelerator mass‐spectrometry dating were used to establish sediment chronology. The fjord‐fill sedimentary succession includes the fjord‐bottom late Weichselian subglacial till of the Last Glacial Maximum, the early Holocene muddy glaciomarine deposits with ice‐rafted debris formed during the fjord deglaciation, and the younger Holocene deposits of a fjord‐head Gilbert‐type delta of which the fluvial distributary plain shows raised alluvial terraces hosting aeolian sedimentation. This sedimentary record of the last glaciation/deglaciation cycle is interpreted in terms of sequence stratigraphy. Zones of epigenetic and syngenetic permafrost are recognized from the vertical distribution of cryofacies, with a conclusion that the formation of permafrost commenced and extended down‐fjord as the fluvio‐deltaic fjord‐fill was gradually reaching subaerial exposure. The upwards‐grown syngenetic permafrost and the top part of downwards‐grown epigenetic permafrost below contain excess ice in a suite of cryofacies indicating ground‐ice segregation and segregative intrusion. The deeper epigenetic permafrost is ice‐poor and contains cryofacies formed solely by segregation processes. This case study may serve as an analogue for other similar Arctic fjord‐valleys where the fjord‐head shoreline was established during the post‐Weichselian deglaciation.

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Glacial Environments

Cited by 23 publications

References 53 publications

Global deglaciation and the re‐appearance of microbial matground‐dominated ecosystems in the late Paleozoic of Gondwana

Global deglaciation and the re‐appearance of microbial matground‐dominated ecosystems in the late Paleozoic of Gondwana

Late Paleozoic paleofjord in the southernmost Parana Basin (Brazil): Geomorphology and sedimentary fill

Late Quaternary sedimentation and permafrost development in a Svalbard fjord‐valley, Norwegian high Arctic

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