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

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