• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 57
  • 5
  • 2
  • 2
  • 2
  • Tagged with
  • 97
  • 97
  • 16
  • 15
  • 12
  • 12
  • 11
  • 11
  • 10
  • 10
  • 10
  • 9
  • 8
  • 8
  • 8
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Meteorological processes controlling the variability of net annual accumulation over the Greenland ice sheet

Bathke, Deborah J., January 2004 (has links)
Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xv, 200 p.; also includes graphics. Includes bibliographical references (p. 173-184).
32

Constraints of the origin of the middle Pleistocene transition from the glacial sedimentary record of the north-central United States /

Roy, Martin. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2004. / Printout. Includes bibliographical references. Also available via the World Wide Web.
33

A study of the dynamics of the British Ice Sheet during Marine Isotope Stages 2 and 3, focusing on Heinrich Events 2 and 4 and their relationship to the North Atlantic glaciological and climatological conditions /

Leigh, Sasha Naomi Bharier. January 2007 (has links)
Thesis (M.Phil.) - University of St Andrews, May 2007.
34

¹⁰Be exposure ages of erratic boulders in southern Norway and implications for the history of the Fennoscandian Ice Sheet /

Goehring, Brent M. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 54-58). Also available on the World Wide Web.
35

Ice Stream Dynamics: A Transition between Sheet Flow and Shelf Flow

Hofstede, Coen Matthijs January 2008 (has links) (PDF)
No description available.
36

A Mass Balance Study of the West Antarctic Ice Sheet

Spikes, Vandy Blue January 2003 (has links) (PDF)
No description available.
37

Surficial Geology and Geomorphology of the Western Olympus Range, Antarctica: Implications for Ice-sheet History

VandenHeuvel, Brett January 2002 (has links) (PDF)
No description available.
38

Late Devensian ice sheet dynamics and the deglaciation of the Hebridean shelf, western Scotland, UK

Arosio, Riccardo January 2017 (has links)
The reconstruction of marine-based paleo ice sheet dynamics can reveal long-term ice sheet activity, and in turn provide constraints on the response of modern marine ice sheets (e.g. the West Antarctica Ice Sheet) to climate change. The marine-terminating Hebrides Ice Stream (HIS) flowed across the western Scottish shelf during the last glacial maximum (3024 ka) and drained a large portion of the northern sector of the British Irish-Ice Sheet (BIIS), affecting its stability. This thesis aims to examine how the HIS evolved and interacted with the changing climate and the underlying landscape after 27 ka. The work is subdivided into: a) an investigation of modern high-resolution bathymetry data coupled with seismic data with the aim of reconstructing deglacial dynamics; b) the analysis of Pb isotopic composition in sediment cores on the shelf in order to locate glacial sediment provenance; c) a study of Hebrides shelf core sedimentology and microfaunal assemblage to reconstruct Lateglacial paleoenvironmental changes. A three-stage deglacial pattern, where topography played a critical role, is defined: i) ice stream margin retreat punctuated by standstills, ii) topography-controlled fjordic retreat, with evolution from a coherent ice-sheet to separate fjord tidewater glaciers, and iii) a stabilisation at the transition from tidewater to land-based ice margins. Between 21 and 15 ka, fine-grained sediments transported by meltwater plumes were the product of erosion of Neoproterozoic basement, while the coarse-grained sediments were instead sourced from island igneous rocks. These results indicate prevailing sediment input from NW Scotland. Lateglacial sediment deposition was strongly influenced by shelf currents and shows wide variation. Therefore, the seismic and sedimentological interpretations need to be considered only on a local scale. Glacimarine sandy deposits in the Muck Deep region support a prolonged glacial occupancy until the latest stages of GS-1 (12.8-11.7 ka), and are at odds with recent studies indicating earlier glacial retreat. The thesis demonstrates the complex interactions between BIIS evolution, subglacial landscape and ocean dynamics. The outcome of this research can be useful to inform future numerical reconstructions.
39

The Dynamics of the Late Neogene Antarctic Ice Sheets in the Central Ross Sea using a Multianalytical Approach

Mallery, Christopher Wallace 06 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / With the goal of determining ice sheet history in the central Ross Sea since the late Miocene, the provenance of glacial till from IODP expedition 374 site U1522 was assessed using a suite of three analyses. A total of 3,869 zircons, between 250-63 microns in size, from sixteen different cores were measured for U-Pb isotopes via LA-ICP-MS. Zircon data was compared to neodymium isotope and clast lithology datasets from collaborators. Site U1522 shows three distinct provenance shifts from the late Miocene to the Pleistocene, two of which are coincident with Ross Sea Unconformities three and two. Late Miocene samples have abundant Cretaceous zircon populations, radiogenic neodymium values, and clasts interpreted as having a West Antarctic provenance. In latest Miocene samples, zircons are mostly Ross Orogeny age (c. 470 615 Ma) and Cretaceous zircon grains are almost absent, neodymium values are relatively un radiogenic, and dolerite clasts are present signaling a shift to East Antarctic derived ice. Above Ross Sea Unconformity 3, early to mid Pliocene samples show a shift back to West Antarctic provenance with abundant Cretaceous zircons and more radiogenic neodymium values. Late Pliocene to Pleistocene samples, deposited above Ross Sea Unconformity 2, reflect dominant East Antarctic provenance with few Cretaceous zircon dates, relatively un radiogenic neodymium values, and the presence of dolerite clasts. These data are broadly in agreement with ice sheet interpretations suggested by clast analysis from ANDRILL site AND-1B. Permo-Triassic zircon dates suggest the presence of unexposed bedrock of this age beneath the West Antarctic Ice Sheet based on their association with Cretaceous dates that have not been reported from East Antarctica. The zircon dataset also reveals two late Miocene intervals with a previously undocumented Eocene Oligocene magmatic event ~30 40 Ma. The coexistence of Cretaceous dates in these intervals suggests a likely West Antarctic source. The absence of Eocene Oligocene zircons in subsequent Plio Pleistocene sediments may be explained by substantial erosion and offshore deposition of the West Antarctic interior, including volcanic edifices following the Middle Miocene Climatic Transition.
40

Folding of stratigraphic layers in ice domes /

Jacobson, Herbert Paul. January 2001 (has links)
Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (p. 104-108).

Page generated in 0.1562 seconds