Significant differences in late Quaternary bedrock erosion and transport: east versus West Greenland ~70°N – evidence from the mineralogy of offshore glacial marine sediments

John Andrews, Anders Anker Bjørk, Dennis Eberl, Anne Jennings, Emily Verplanck

    15 Citations (Scopus)

    Abstract

    We use quantitative X-ray diffraction to determine the mineralogy of late Quaternary marine sediments from the West and East Greenland shelves offshore from early Tertiary basalt outcrops. Despite the similar basalt outcrop area (60 000-70 000km2), there are significant differences between East and West Greenland sediments in the fraction of minerals (e.g. pyroxene) sourced from the basalt outcrops. We demonstrate the differences in the mineralogy between East and West Greenland marine sediments on three scales: (1) modern day, (2) late Quaternary inputs and (3) detailed down-core variations in 10 cores from the two margins. On the East Greenland Shelf (EGS), late Quaternary samples have an average quartz weight per cent of 6.2±2.3 versus 12.8±3.9 from the West Greenland Shelf (WGS), and 12.02±4.8 versus 1.9±2.3wt% for pyroxene. K-means clustering indicated only 9% of the samples did not fit a simple EGS vs. WGS dichotomy. Sediments from the EGS and WGS are also isotopically distinct, with the EGS having higher ε{lunate}Nd (-18 to 4) than those from the WGS (ε{lunate}Nd=-25 to -35). We attribute the striking dichotomy in sediment composition to fundamentally different long-term Quaternary styles of glaciation on the two basalt outcrops.

    Original languageEnglish
    JournalJournal of Quaternary Science
    Volume30
    Issue number5
    Pages (from-to)452-463
    Number of pages12
    ISSN0267-8179
    DOIs
    Publication statusPublished - 1 Jul 2015

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