TY - JOUR
T1 - Scratching the Surface
T2 - A Marine Sediment Provenance Record From the Continental Slope of Central Wilkes Land, East Antarctica
AU - Tooze, Sian
AU - Halpin, Jacqueline A.
AU - Noble, Taryn L.
AU - Chase, Zanna
AU - O'Brien, Philip E.
AU - Armand, Leanne
N1 - Publisher Copyright:
©2020. The Authors.
PY - 2020/11
Y1 - 2020/11
N2 - The geology of Wilkes Land, East Antarctica, is masked by kilometers of ice and remains largely unexplored. Defining the sediment provenance adjacent to this hidden region is important for distinguishing the proximal subglacial basement terranes and refining the dynamic regional glaciological history. This study presents a detrital sediment provenance record spanning c. 23.5 ka from the continental slope of central Wilkes Land. Sediment provenance was characterized using U-Pb geochronology and trace element geochemistry from detrital zircon, titanite and apatite, and Pb isotopic signatures from detrital feldspar. These data were compared with new feldspar Pb-isotopic signatures and existing U-Pb zircon data sets from rare nearby coastal outcrop. A principally igneous source was revealed with dominant age populations between c. 1,360-1,100 Ma and c. 1,620-1,490 Ma, characteristic of rocks of the proximal Wilkes and Banzare provinces, respectively. Minor detritus was additionally sourced from the proximal Nuyina Province (c. 1,450-1,390 Ma). Temporal variation in the climate and ice sheet configuration are likely responsible for subtle downcore changes observed in detrital sediment provenance. High sedimentation rates during the glacial period suggest reworking of continental shelf sediments and downslope transport in debris flows during ice sheet advance. Glacial meltwater fluxes fed largely by the Totten Glacier were responsible for supplying detritus during deglaciation. During interglacials, detritus was derived from a broad coastal region and delivered to the slope via multiple glacial outlets. These results present the first substantial offshore evidence to support recent interpretations that the subglacial crust of central Wilkes Land has a dominantly Mesoproterozoic history.
AB - The geology of Wilkes Land, East Antarctica, is masked by kilometers of ice and remains largely unexplored. Defining the sediment provenance adjacent to this hidden region is important for distinguishing the proximal subglacial basement terranes and refining the dynamic regional glaciological history. This study presents a detrital sediment provenance record spanning c. 23.5 ka from the continental slope of central Wilkes Land. Sediment provenance was characterized using U-Pb geochronology and trace element geochemistry from detrital zircon, titanite and apatite, and Pb isotopic signatures from detrital feldspar. These data were compared with new feldspar Pb-isotopic signatures and existing U-Pb zircon data sets from rare nearby coastal outcrop. A principally igneous source was revealed with dominant age populations between c. 1,360-1,100 Ma and c. 1,620-1,490 Ma, characteristic of rocks of the proximal Wilkes and Banzare provinces, respectively. Minor detritus was additionally sourced from the proximal Nuyina Province (c. 1,450-1,390 Ma). Temporal variation in the climate and ice sheet configuration are likely responsible for subtle downcore changes observed in detrital sediment provenance. High sedimentation rates during the glacial period suggest reworking of continental shelf sediments and downslope transport in debris flows during ice sheet advance. Glacial meltwater fluxes fed largely by the Totten Glacier were responsible for supplying detritus during deglaciation. During interglacials, detritus was derived from a broad coastal region and delivered to the slope via multiple glacial outlets. These results present the first substantial offshore evidence to support recent interpretations that the subglacial crust of central Wilkes Land has a dominantly Mesoproterozoic history.
KW - Antarctic geology
KW - East Antarctica
KW - Wilkes Land
KW - geochemistry
KW - geochronology
KW - sediment provenance
UR - http://www.scopus.com/inward/record.url?scp=85096419931&partnerID=8YFLogxK
U2 - 10.1029/2020GC009156
DO - 10.1029/2020GC009156
M3 - Article
SN - 1525-2027
VL - 21
JO - Geochemistry, Geophysics, Geosystems
JF - Geochemistry, Geophysics, Geosystems
IS - 11
M1 - e2020GC009156
ER -