Late Cenozoic oscillations of Antarctic ice sheets revealed by provenance of basement clasts and grain detrital modes in ANDRILL core AND-1B

Abstract

Tim, "Late Cenozoic oscillations of Antarctic ice sheets revealed by provenance of basement clasts and grain detrital modes in ANDRILL core AND-1B" (2011). ANDRILL Research and Publications. 48.

Early Miocene basement clasts in ANDRILL AND-2A core and their implications for paleoenvironmental changes in the McMurdo Sound region (western Ross Sea, Antarctica)

“…Despite some down-core variability, the compositions of clast-poor and finer-grained facies are generally dominated by local volcanic products (mainly primary deposits but also reworked felsic/intermediate lavas) whereas associated clast-rich facies (e.g., diamictites and conglomerate) show a more varied clast assemblage with more abundant basement clasts. A similar pattern was reported by Talarico and Sandroni (2009) and Talarico et al (2010) in the AND-1B core where appears to be coincident with changes in sedimentary processes over the glacial/interglacial cycle. Similarly, fine-grained lithofacies in AND-2A core include a variable content of lonestones of basement lithologies suggesting (as detailed below) major calving processes in areas such as the northern side of present-day Mount Morning (where both volcanic and metamorphic bedrock is present) with possible pinning of ice tongues between Teall Island and the southern tip of Skelton Glacier.…”

“…In analogy with the results of numerical modelling for younger record (b5 Ma; Pollard and DeConto, 2009), provenance models in the Late Miocene to Pleistocene AND-1B core record Talarico et al, 2010) and LGM glacial models (e.g., Hughes, 2000, 2002), the reconstructed ice-flow patterns based on the investigated AND-2A core section are consistent with fluctuation of the WAIS. However, conclusive evidence for such hypothesis waits for new numerical modellings and it will be unambiguously found by means of new drilling in the eastern Ross Sea.…”

“…Here below we summarise the main data constraining the three source areas. It is worth mentioning that clasts of both assemblages B and C also occur in the AND-1B core and additional detailed petrographical descriptions can be found in Talarico et al (2010) and in Talarico and Sandroni (2009).…”

“…Moreover the new data can contribute new constrains on provenance reconstructions previously proposed for the supply of glacigenic sediments in different drill site areas and with different methods and materials (e.g., petrology of gravel-fraction: Sandroni and Talarico, 2004;Talarico et al, 2010;clay mineralogy: Ehrmann et al, 2005;Franke and Erhmann, 2010; bulk rock geochemistry: Monien et al, 2010).…”

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“…A total of 7454 WBD spikes were identifi ed; this is ~11% of the total WBD measurements, compared to a total of 86,333 counted clasts Talarico et al, 2011). Regression plots (Fig.…”