The Transantarctic Mountains (TAM) are one of Earth's great mountain belts and are a fundamental physiographic feature of Antarctica. They are continental-scale, traverse a wide range of latitudes, have high relief, contain a significant proportion of exposed rock on the continent, and represent a major arc of environmental and geological transition. Although the modern physiography is largely of Cenozoic origin, this major feature has persisted for hundreds of millions of years since the Neoproterozoic to the modern. Its mere existence as the planet's longest intraplate mountain belt at the transition between a thick stable craton in East Antarctica and a large extensional province in West Antarctica is a continuing enigma. The early and more cryptic tectonic evolution of the TAM includes Mesoarchean and Paleoproterozoic crust formation as part of the Columbia supercontinent, followed by Neoproterozoic rift separation from Laurentia during breakup of Rodinia. Development of an Andean-style Gondwana convergent margin resulted in a long-lived Ross orogenic cycle from the late Neoproterozoic to the early Paleozoic, succeeded by crustal stabilization and widespread denudation during early Gondwana time, and intra-cratonic and foreland-basin sedimentation during late Paleozoic and early Mesozoic development of Pangea. Voluminous mafic volcanism, sill emplacement, and layered igneous intrusion are a primary signature of hotspot-influenced Jurassic extension during Gondwana breakup. The most recent phase of TAM evolution involved tectonic uplift and exhumation related to Cenozoic extension at the inboard edge of the West Antarctic Rift System, accompanied by Neogene to modern glaciation and volcanism related to the McMurdo alkaline volcanic province. Despite the remote location and relative inaccessibility of the TAM, its underlying varied and diachronous geology provides important clues for reconstructing past supercontinents and influences the modern flow patterns of both ice and atmospheric circulation, signifying that the TAM have both continental and global importance through time.
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I am fortunate to have had the opportunity to work with many wonderful colleagues over a period of years, including Vickie Bennett, David Dallmeyer, Don DePaolo, Mark Fanning, Carol Finn, Vicki Hansen, Kathy Licht, Paul Myrow, Mike Pope, Bert Rowell, Jeff Vervoort, Nick Walker, and Ian Williams. I owe a special debt to Scott Borg who very trustingly invited me to participate in my first Antarctic field work in 1985; his introduction launched a lifelong passion. I thank several colleagues who provided generous feedback on sections of an earlier manuscript, including Allan Ashworth, Jim Collinson, David Elliot, Paul Fitzgerald, Georg Kleinschmidt, and Phil Kyle; all shortcomings are my responsibility. Spencer Niebuhr of the Polar Geospatial Center at the University of Minnesota helped make the DEMs used in some of the figures. The manuscript was substantially improved by very constructive comments from Christine Siddoway and an anonymous reviewer, for which I am thankful. Last, I am grateful to the NSF Office of Polar Programs for support of field research projects.
- Intraplate mountains