Landscape development of the Transantarctic Mountains, Shackleton Glacier area, Antarctica: An integration of structural geology, geomorphology, and apatite fission-track thermochronology

Abstract

Models of the evolution of the modern Transantarctic Mountains, the uplifted flank of the West Antarctic rift system, require constraints on the timing, magnitude, and spatial pattern of surface uplift, rock uplift, denudation, and faulting. This study presents a model of Cenozoic landscape development for the Shackleton Glacier area (85°S, 176°W) by integrating structural geologic, geomorphologic, and apatite fission-track thermochronologic (AFTT) methods. Cenozoic denudation (up to 5-6 km) began ∼50 Ma near the Ross Ice Shelf coast and migrated inland by escarpment retreat, as evidenced in the AFTT and geomorphologic record. Dissected planation surfaces are scattered at elevations from 500 m to almost 4000 m above sea level and represent episodes of relative tectonic quiescence between periods of uplift. The fault structure of the range front is consistent with an interpretation of dextrally transtensional kinematics, which apparently accommodates a smaller transcurrent component than the greater West Antarctic rift system.