A petrologic study of Weddell Sea sediments: implications for provenance and glacial history

Simple item page
dc.contributor.advisorAnderson, John B.en_US
dc.contributor.committeeMemberBaker, Donald R.en_US
dc.contributor.committeeMemberBally, Albert W.en_US
dc.creatorAndrews, Barbara Annen_US
dc.date.accessioned2018-12-18T21:15:27Zen_US
dc.date.available2018-12-18T21:15:27Zen_US
dc.date.issued1984en_US
dc.description.abstractKnowledge of subglacial geology in Antarctica is restricted due to limited outcrop exposure. Investigations of terrestrially derived sediments deposited on the Antarctic continental margin have proved successful for gaining increased understanding of this ice-covered continent. Petrologic analyses conducted on glacial, glacial marine, and sediment gravity flow deposits from the Weddell Sea continental margin provide important evidence concerning subglacial geology and glacial history of land areas contiguous to the Weddell Sea. Petrologic data validates identifications, originally based on sed imen to 1ogic criteria, of basal tills on the Weddell Sea continental shelf. The presence of basal tills indicates a major expansion and coincident grounding of the East or West Antarctic Ice Sheet to the shelf edge. Petrologic evidence suggests that glacial expansion in the area of study was chiefly that of the East Antarctic Ice Sheet. Basal tills and transitional glacial marine sediments form distinct petrologic provinces on the Weddell Sea shelf. Most province boundaries extend inland parallel to ii reconstructed ice paleoflow lines. Till lithologies are dominated by volcanics and quartzose sedimentary rocks, in contrast to metamorphic outcrops of the Weddell Sea region. Comminution does not effectively bias till composition. Till lithologies suggest that mountainous outcrops are not representative of subglacial geology and that sedimentary basins exist beneath the Antarctic Ice Sheet. Four provenance areas for the Weddell Sea basal tills are modeled; correlations between modeled provenance areas and till petrologic provinces are good. Ice-rafted lithologies are limited in number and do not show the expected varied assemblage of Antarctic rock types. Derivation from a limited source area or from lateral moraines is suggested. Sediment gravity flow deposits from the Weddell Sea continental slope and abyssal plain are compositionally very different. Intracanyon slope debris flows and turbidites, composed chiefly of lithic fragments, were generated from basal tills on the adjacent shelf. Abyssal plain turbidites show substantial quartz enrichment and could not have been sourced directly from shelf tills.en_US
dc.format.digitalOriginreformatted digitalen_US
dc.format.extent211 ppen_US
dc.identifier.callnoThesis Geol. 1984 Andrewsen_US
dc.identifier.citationAndrews, Barbara Ann. "A petrologic study of Weddell Sea sediments: implications for provenance and glacial history." (1984) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/103936">https://hdl.handle.net/1911/103936</a>.en_US
dc.identifier.digitalRICE1562en_US
dc.identifier.urihttps://hdl.handle.net/1911/103936en_US
dc.language.isoengen_US
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.titleA petrologic study of Weddell Sea sediments: implications for provenance and glacial historyen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentEarth Scienceen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Artsen_US
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
RICE1562.pdf
Size:
6.84 MB
Format:
Adobe Portable Document Format
Download
Collections
Rice University Theses and Dissertations