What caused the uplift of the Transantarctic Mountains, Antarctica?
These mountains have long been interpreted as a classic rift-flank uplift, yet we have known that the episode of greatest denudation in the mountain range post-dated the main phase of extension in the West Antarctic Rift System (WARS) by >30 Myr. Since the late 1980s, there has been considerable controversy, as well, over their neotectonic activity, with some papers suggesting kilometers of surface uplift since the Pliocene. Using apatite fission-track (AFT) thermochronology, Paul Fitzgerald, Suzanne Baldwin (both at Syracuse University) and I have determined that rapid denudation and normal faulting across the subaerial rift margin—Transantarctic Mountains front (TMF)—did not commence near the Shackleton Glacier (88°S, 180°W) until ~40 Ma, about 15 Myr later than in the Dry Valleys area rather northwest or ~45 Myr after rifting initiated in the WARS. Furthermore, erosion surfaces that we infer to be non-glacial in origin and show little offset across the TMF indicate that widespread faulting across the TMF ceased by probably no later than 14 Ma. Since then, rock uplift of the Transantarctic Mountains has been due to faulting along the Ross Ice Shelf margin and has been limited to 300-700 m. [Miller et al., 2001, Terra Antartica; Miller et al., in preparation].
Oblique air photo and perspective view of 200 m resolution DEM of Transantarctic Mountains front in the study area. The mountain range ascends from near sea-level at the Ross Ice Shelf to just above 4000 m at Mt. Wade.
Cross-section (bottom) and denudation profile (top) of Tranantarctic Mountains at the study area. Fault locations and amounts of fault offset in the TMF were determined from AFT thermochronology.