Sedimentological Investigations of Paleo-Ice Sheet Dynamics in West Antarctica

Simple item page
dc.contributor.advisorAnderson, John B.en_US
dc.contributor.committeeMemberDasgupta, Rajdeepen_US
dc.contributor.committeeMemberHight, Christopheren_US
dc.contributor.committeeMemberGordon, Richard G.en_US
dc.creatorKirshner, Alexandraen_US
dc.date.accessioned2013-09-16T15:16:14Zen_US
dc.date.accessioned2013-09-16T15:16:55Zen_US
dc.date.available2013-09-16T15:16:14Zen_US
dc.date.available2013-09-16T15:16:55Zen_US
dc.date.created2013-05en_US
dc.date.issued2013-09-16en_US
dc.date.submittedMay 2013en_US
dc.date.updated2013-09-16T15:16:56Zen_US
dc.description.abstractModern Pine Island and Thwaites Glaciers, which both drain into Pine Island Bay, are some of the fastest moving portions of the cryosphere and may be the most unstable ice streams in Antarctica. I examined over 133 cores to conduct a detailed sedimentological facies analysis. These data, augmented by new radiocarbon and 210Pb dates, and bathymetric data, are used to reconstruct the post-LGM deglacial history of PIB and gain a better understanding of the causes of ice sheet retreat. My results record a clear retreat stratigraphy in PIB composed of, from top to base; terrigenous sandy silt (plumite), pebbly sandy mud (ice-proximal glacimarine), and till. Initial retreat from the outer-continental shelf began shortly after the LGM and before 16.4 k cal yr BP, in response to rising sea level. Bedforms in outer PIB document episodic retreat in the form of back-stepping grounding zone wedges and are associated with proximal glacimarine sediments. A sub-ice shelf facies is observed in central PIB that spans ∼12.3–10.6 k cal yr BP. Widespread impingement of warm water onto the continental shelf caused an abrupt change from sub-ice shelf sedimentation to distal glacimarine sedimentation dominated by dispersal of terrigenous silt between 7.8 and 7.0 k cal yr BP. The uppermost sediments in Pine Island Bay were hydrodynamically sorted by meltwater plumes. Inner Pine Island Bay contains several large basins that are linked by channels. The most recent release of sediment coincides with rapid retreat of the grounding line, and has an order of magnitude greater flux relative to the entire unit, indicating episodic sedimentation. This is the first identification of a meltwater-derived deposit in Antarctica and demonstrates that punctuated meltwater-intensive glacial retreat occurred at least three times throughout the Holocene in this region. Quartz sand grains were used to conduct an analysis of mode of transport for sediments in the Antarctic Peninsula region from the Eocene to present to record the onset of glaciation. Glacial transport imparts a unique suite of microtextures on quartz grains from high shear-stresses. Eocene samples are free of glacial influence. Late Eocene samples show the inception of glacially derived high-stress microtextures, marking the onset of alpine glaciation. Oligocene grains are similar to the late Eocene samples. Middle Miocene microtextures are characteristic of transport from far-field large ice sheets, originating from ice rafting from the West Antarctic Ice Sheet. The Pliocene and Pleistocene samples indicate the existence of the northern Antarctic Peninsula Ice Sheet at this time, consistent with other proxies.en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.citationKirshner, Alexandra. "Sedimentological Investigations of Paleo-Ice Sheet Dynamics in West Antarctica." (2013) Diss., Rice University. <a href="https://hdl.handle.net/1911/71973">https://hdl.handle.net/1911/71973</a>.en_US
dc.identifier.slug123456789/ETD-2013-05-241en_US
dc.identifier.urihttps://hdl.handle.net/1911/71973en_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.subjectPine Island Bayen_US
dc.subjectAmundsen Seaen_US
dc.subjectLast glacial maximumen_US
dc.subjectPine Island Glacieren_US
dc.subjectSubglacial meltwateren_US
dc.subjectGlacial historyen_US
dc.subjectGlacial retreaten_US
dc.subjectGrounding line stabilityen_US
dc.subjectIce streamen_US
dc.subjectWarm deep wateren_US
dc.subjectSHALDRILen_US
dc.subjectAntarctic Peninsulaen_US
dc.subjectMicromorphologyen_US
dc.titleSedimentological Investigations of Paleo-Ice Sheet Dynamics in West Antarcticaen_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.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
KIRSHNER-THESIS.pdf
Size:
55.16 MB
Format:
Adobe Portable Document Format
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.61 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Rice University Theses and Dissertations