Exhumation history along the eastern Amundsen Sea coast, West Antarctica, revealed by low‐temperature thermochronology. Issue 10 (6th October 2016)

• Record Type: Journal Article
• Authors: Lindow, Julia; Kamp, Peter J. J.; Mukasa, Samuel B.; Kleber, Michel; Lisker, Frank; Gohl, Karsten; Kuhn, Gerhard; Spiegel, Cornelia
• Is Part Of: Tectonics. Volume 35:Issue 10(2016)
• Page Start: 2239
• Page End: 2257
• Publication Date: 2016-10-06
• Subjects: low‐temperature thermochronology -- Pine Island Bay -- West Antarctica -- ice rafted debris -- fission track dating -- apatite helium dating; Geology, Structural -- Periodicals; 551.8
• DOI: 10.1002/2016TC004236
• Languages: English
• ISSNs: 0278-7407

Abstract

Abstract: 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. Key Points: Reconstruction of the thermotectonic history along the Amundsen Sea Coast Time‐temperature modeling suggests late Cretaceous postorogenic gravitational collapse Low‐temperature thermochronology reveals Cenozoic crustal tilting in Pine Island Bay