Uplift and exhumation of the Tranantarctic Mountains

This data set is a paper published in Earth and Planetary Science Letters
concerning the mid-Cretaceous through mid-Cenozoic tectonic evolution of west
Antarctica. Follows is the abstract.

Two distinct stages of extension are recognized in the West Antarctic Rift
system (WARS). During the first stage, beginning in the Late Cretaceous,
extension was broadly distributed throughout much of West Antarctica. A second
stage of extension in the late Paleogene was focused primarily in the Victoria
Land Basin, near the boundary with the East Antarctic craton. The transition to
focused extension was roughly coeval with volcanic activity and strike–slip
faulting in the adjacent Transantarctic Mountains. This spatial and temporal
correspondence suggests that the transition in extensional style could be the
result of a change in plate motions or impingement of a plume. Here we use
finite element models to study the processes and conditions responsible for the
two-stage evolution of rifting in the WARS. Model results indicate that the
transition from a prolonged period of broadly distributed extension to a later
period of focused rifting did not require a change in the regional stress
regime (changes in plate motion), or deep mantle thermal state (impingement of
a plume). Instead, we attribute the transition from diffuse to focused
extension to an early stage dominated by the initially weak accreted
lithosphere of West Antarctica, and a later stage that concentrated around a
secondary weakness located at the boundary between the juvenile West Antarctica
lithosphere and Precambrian East Antarctic craton. The modeled transition in
extension from the initially weak West Antarctica region to the secondary
weakness at the West Antarctic–East Antarctic boundary is precipitated by
strengthening of the West Antarctica lithosphere during syn-extensional
thinning and cooling. The modeled synextensional strengthening of the WARS
lithosphere promotes a wide-rift mode of extension between 105 and about 65 Ma.
By about 65 Ma most of the extending WARS region becomes stronger than the area
immediately adjacent to the East Antarctic craton and extension becomes
concentrated near the East Antarctic/West Antarctic boundary, forming the
Victoria Land Basin region. Mantle necking in this region leads to
syn-extensional weakening that promotes a narrow-rift mode of extension that
becomes progressively more focused with time, resulting in formation of the
Terror Rift in the western Victoria Land Basin. The geodynamic models
demonstrate that the transition from diffuse to focused extension occurs only
under a limited set of initial and boundary conditions, and is particularly
sensitive to the pre-rift thermal state of the crust and upper mantle. Models
that predict diffuse extension in West Antarctica followed by localization of
rifting near the boundary between East and West Antarctica require upper mantle
temperatures of 730±50 °C and sufficient concentration of heat producing
elements in the crust to account for about 50% of the upper mantle
temperature.
Models with upper mantle temperatures bca. 680 °C and/or less crustal heat
production initially undergo diffuse extension in West Antarctica, and quickly
develop a lithospheric neck at the model edge furthest from East Antarctica.
Models with upper mantle temperatures >ca. 780 °C do not develop focused rifts,
and predict indefinite diffuse extension in West Antarctica.