Exhumation history along the eastern Amundsen Sea coast, West Antarctica, revealed by low-temperature thermochronology

West Antarctica experienced a complex tectonic history, which is still poorly documented, in part due to extensive ice cover. Here we reconstruct the Cretaceous to present thermotectonic history of Pine Island Bay area and its adjacent coasts, based on a combination of apatite and zircon fission tra...

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Bibliographic Details
Published in:Tectonics
Main Authors: Lindow, Julia, Kamp, Peter J.J., Mukasa, Samuel B., Kleber, Michel, Lisker, Frank, Gohl, Karsten, Kuhn, Gerhard, Spiegel, Cornelia
Format: Article in Journal/Newspaper
Language:English
Published: American Geophysical Union 2016
Subjects:
Science & Technology
Physical Sciences
Geochemistry & Geophysics
MARIE BYRD LAND
FISSION-TRACK ANALYSIS
PINE ISLAND BAY
ICE-SHEET
RADIATION-DAMAGE
THERMAL HISTORY
TRANSANTARCTIC MOUNTAINS
DIFFUSION KINETICS
STOPPING DISTANCES
CRUSTAL STRUCTURE
Antarctic
West Antarctica
Amundsen Sea
Transantarctic Mountains
Pacific
Byrd
Marie Byrd Land
Tilting
Island Bay
Pine Island Bay
Thwaites Glacier
Thurston
Thurston Island
Pine Island Trough
Antarc*
Antarctica
Ice Sheet
Pine Island
Online Access:https://hdl.handle.net/10289/11078
https://doi.org/10.1002/2016TC004236
Description
Summary:West Antarctica experienced a complex tectonic history, which is still poorly documented, in part due to extensive ice cover. Here we reconstruct the Cretaceous to present thermotectonic history of Pine Island Bay area and its adjacent coasts, based on a combination of apatite and zircon fission track and apatite (U-Th-Sm)/He thermochronology. In addition, we report petrographic information for the catchments of Pine Island, Thurston Island, and Thwaites glaciers. Our data suggest that the underlying bedrock of the Pine Island and Thwaites Glacier catchments are very different and vary from granitoids to (Cenozoic?) volcanogenic sequences and low-grade metamorphics. Our thermochronology data show that the upper crustal rocks of Pine Island Bay experienced very rapid cooling during the late Cretaceous. We attribute this rapid cooling of basement rocks and associated reduction in mean elevation to tectonic denudation driven by gravitational collapse of the Cretaceous orogen along the proto-Pacific Gondwana margin. Rapid Cretaceous crustal cooling was followed by very slow cooling during the Cenozoic, with no erosional response—within the limits of thermochronological methods—to the onset of glaciation and subsequent climatic changes. Cenozoic rifting within the West Antarctic Rift appears to have had little effect on erosion processes around Pine Island Bay; instead, our data suggest Cenozoic crustal tilting toward Pine Island Trough, a major geomorphic feature previously suggested to be a branch of the rift system.

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