Analysis of Antarctic glacigenic sediment provenance through geochemical and petrologic applications

Abstract

Highlights  Antarctica is a patchwork of geological terrains with distinct geologic histories  Antarctica's ice cover makes its geologic history cryptic  Antarctica's glacigenic sediment provenance reveals ice sheet and geologic history  Provenance approaches applied to Antarctica's glacigenic sediments are synthesized  Multiproxy approaches provide the most robust provenance assessments

Geochemical fingerprints of glacially eroded bedrock from West Antarctica: Detrital thermochronology, radiogenic isotope systematics and trace element geochemistry in Late Holocene glacial-marine sediments

“…Approach and samples 3.1. Approach to provenance fingerprinting Analysis of the provenance of marine detrital sediments requires the consideration of a variety of glaciological and geological factors (see review by Licht and Hemming, 2017). Glacial influence on provenance records is exerted by preferential subglacial erosion of specific substrates.…”

Expedition 382 Preliminary Report: Iceberg Alley and Subantarctic Ice and Ocean Dynamics

“…For example, the 40 Ar/ 39 Ar age of a single hornblende (or mica) IBRD grain allows it to be traced to a source on the continent with a similar 40 Ar/ 39 Ar age, and a population of ~30 hornblende grains should show which sources are most actively exporting debris in icebergs, which is information critical to reconstructing the past history of the AIS (e.g., Williams et al, 2010;Pierce et al, 2014). Similarly, Pb-Pb and 40 Ar/ 39 Ar in feldspars (e.g., Flowerdew et al, 2013), U-Pb in zircons (e.g., Pierce et al, 2014), and other thermochronometers (e.g., reviewed in Licht and Hemming, 2017) can distinguish input from different source areas. Combining these mineral tracers should lead to more accurate identification of provenance and hence the spatial history of AIS glaciation.…”

“…Although some overlap occurs between the radiogenic isotopes from East and West Antarctica (Roy et al, 2007), broadly there is considerably older crust (and thus lower ε Nd and ε Hf and higher 87 Sr/ 86 Sr) from East Antarctic sources. In some cases, the provenance information from sand and fine fractions can provide contrasting evidence (e.g., Cook et al, 2017;Licht and Hemming, 2017), so it is important to examine both. Other geochemical tracers, especially radiogenic isotopes systems such as Rb-Sr, U-Th-Pb, Lu-Hf, and K-Ar are likely to provide greater clarity in the assessment of mixing from difference sources.…”

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“…For example, the 40 Ar/ 39 Ar age of a single hornblende (or mica) IBRD grain allows it to be traced to a source on the continent with a similar 40 Ar/ 39 Ar age, and a population of ~30 hornblende grains should show which sources are most actively exporting debris in icebergs, which is information critical to reconstructing the past history of the AIS (e.g., Roy et al, 2007;Williams et al, 2010;Pierce et al, 2011Pierce et al, , 2014. Similarly, Pb-Pb and 40 Ar/ 39 Ar in feldspars (e.g., Hemming and Rasbury, 2000;Flowerdew et al, 2013), U-Pb in zircons (e.g., Pierce et al, 2014), and other thermochronometers (e.g., reviewed in Licht and Hemming, 2017) can distinguish input from different source areas. Combining these mineral tracers should lead to more accurate identification of provenance and hence the spatial history of AIS glaciation.…”