388 research outputs found

    The glacial diversion of the Que and Bulgobac Rivers, western Tasmania.

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    Glacier ice diverted the courses of the upper Que and Bulgobac Rivers from a direct route to the Pieman River through the Que Gorge to the Huskisson River. The diversion probably occurred in the Early Pleistocene but the drainage pattern established was maintained and perhaps accentuated by further glaciation during the Middle Pleistocene. The modern drainage pattern is a palimpsest of that which existed by late Middle Pleistocene times

    Weathering and morphostratigraphic evidence for four glaciations in the Henty River Basin, western Tasmania

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    The Quaternary glacial histories of the Pieman and Henty River Basins have largely been developed by using post-depositional weathering criteria to identify and map the drift sheets

    The influence of Antarctic subglacial volcanism on the global iron cycle during the Last Glacial Maximum

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    Marine sediment records suggest that episodes of major atmospheric CO2 drawdown during the last glacial period were linked to iron (Fe) fertilisation of subantarctic surface waters. The principal source of this Fe is thought to be dust transported from southern mid-latitude deserts. However, uncertainty exists over contributions to CO2 sequestration from complementary Fe sources, such as the Antarctic ice sheet, due to the difficulty of locating and interrogating suitable archives that have the potential to preserve such information. Here we present petrographic, geochemical and microbial DNA evidence preserved in precisely dated subglacial calcites from close to the East Antarctic Ice Sheet margin, which together suggest that volcanically-induced drainage of Fe-rich waters during the Last Glacial Maximum could have reached the Southern Ocean (SO). Our results support a significant contribution of Antarctic volcanism to subglacial transport and delivery of nutrients with implications on ocean productivity at peak glacial conditions
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