Indiana University-Purdue University Indianapolis (IUPUI) / Petrography of the sand fraction, particle size analysis, and detrital zircon U/Pb isotope data, and pebble count data were collected from Byrd Glacier moraines and central/western Ross Sea till in order to study the glacially-driven sedimentological dynamics of the Byrd Glacier and to trace material transported from the Byrd Glacier into the Ross embayment. Most of the petrographic data show evidence of local derivation with the exception of the sites from the Lonewolf Nunataks as indicated by exotic rock types within the sand and pebble fractions. This, in conjunction with particle-size data of the samples from the Lonewolf Nunataks indicate that material from underneath the East Antarctic Ice Sheet (EAIS) is being transported to the surface and deposited in this area. The U/Pb ages of zircons from the Byrd Glacier show dominant populations of Ross to Pan-African ages (~533 - 610 Ma) with varying populations of older (Grenville to Archean) zircons. Late Precambrian (~588 – 610 Ma) aged detrital zircons in samples from the head of the Byrd Glacier are older than other dated grains found in the vicinity and may be evidence of early development of the Ross belt or represent evidence of sub-glacial extension of the Mozambique structure found in Dronning Maud Land. The west central Ross Sea till samples have a variety of mineral and lithic fragments that include a dominant population of polymict at certain depth intervals. Detrital zircon data suggests the potential provenance of two of these intervals may be derived from Marie Byrd Land and possibly the Byrd Glacier. Using sand petrography and U/Pb detrital zircon age dating, positive correlation was found between specific samples from the head of the Byrd Glacier and the western Ross Sea. The ice-sheet flow models of Stuiver et al. (1981), Licht and Fastook (1998), and Licht et al. (2005) each show potential support from aspects of this study. It is possible that dynamic ice-flow regime changes of the West and East Antarctic Ice Sheets into the Ross Sea may have occurred some time during the LGM as suggested by geochemical and petrographical evidence found within intervals of central and western Ross Sea cores.

abstract: The Byrd Glacier region of Antarctica is important for understanding the tectonic development and landscape evolution of the Transantarctic Mountains (TAM). This outlet glacier crossing the TAM marks a major discontinuity in the Neoproterozoic-early Paleozoic Ross orogen. The region has not been geologically mapped in detail, but previous studies have inferred a fault to exist beneath and parallel to the direction of flow of Byrd Glacier. Thermochronologic analysis has never been undertaken across Byrd Glacier, and little is known of the exhumation history of the region. The objectives of this study are to assess possible differential movement across the inferred Byrd Glacier fault, to measure the timing of exhumation, and to gain a better overall understanding of the structural architecture of the TAM. Apatites and zircons separated from rock samples collected from various locations north and south of Byrd Glacier were dated using single-crystal (U- Th)/He analysis. Similar cooling histories were revealed with comparable exhumation rates of 0.03 ± 0.003 and 0.04 ± 0.03 mm/yr north and south of Byrd Glacier from apatite data and somewhat similar rates of 0.06 ± 0.008 and 0.04 ± 0.01 mm/yr north and south of Byrd Glacier from zircon data. Age vs. elevation regressions indicate a vertical offset of 1379 ± 159 m and 4000 ± 3466 m from apatite and zircon data. To assess differential movement, the Kukri Peneplain (a regional unconformity) was utilized as a datum. On-site photographs, Landsat imagery, and Aster Global DEM data were combined to map Kukri Peneplain elevation points north and south of Byrd Glacier. The difference in elevation of the peneplain as projected across Byrd Glacier shows an offset of 1122 ± 4.7 m. This study suggests a model of relatively uniform exhumation followed by fault displacement that uplifted the south side of Byrd Glacier relative to the north side. Combining apatite and zircon (U-Th)/He analysis along with remote geomorphologic analysis has provided an understanding of the differential movement and exhumation history of crustal blocks in the Byrd Glacier region. The results complement thermochronologic and geomorphologic studies elsewhere within the TAM providing more information and a new approach. / Dissertation/Thesis / M.S. Geological Sciences 2011

Thesis (M.S.)--Indiana University, 2008. / Department of Earth Sciences, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Kathy J. Licht, Andrew P. Barth, R. Jeffery Swope, Gabriel M. Filippelli. Includes vitae. Includes bibliographical references (leaves 182-191).