No abstract available

Doctor of Philosophy(PhD) / Mid-ocean ridges are a fundamental but insufficiently understood component of the global plate tectonic system. Mid-ocean ridges control the landscape of the Earth's ocean basins through seafloor spreading and influence the evolution of overriding plate margins during midocean ridge subduction. The majority of new crust created at the surface of the Earth is formed at mid-ocean ridges and the accretion process strongly influences the morphology of the seafloor, which interacts with ocean currents and mixing to influence ocean circulation and regional and global climate. Seafloor spreading rates are well known to influence oceanic basement topography. However, I show that parameters such as mantle conditions and spreading obliquity also play significant roles in modulating seafloor topography. I find that high mantle temperatures are associated with smooth oceanic basement, while cold and/or depleted mantle is associated with rough basement topography. In addition spreading obliquities greater than > 45° lead to extreme seafloor roughness. These results provide a predictive framework for reconstructing the seafloor of ancient oceans, a fundamental input required for modelling ocean-mixing in palaeoclimate studies. The importance of being able to accurately predict the morphology of vanished ocean floor is demonstrated by a regional analysis of the Adare Trough, which shows through an analysis of seismic stratigraphy how a relatively rough bathymetric feature can strongly influence the flow of ocean bottom currents. As well as seafloor, mid-ocean ridges influence the composition and morphology of overriding plate margins as they are consumed by subduction, with implications for landscape and natural resources development. Mid-ocean ridge subduction also effects the morphology and composition of the overriding plate margin by influencing the tectonic regime experienced by the overriding plate margin and impacting on the volume, composition and timing of arc-volcanism. Investigation of the Wharton Ridge slab window that formed beneath Sundaland between 70 Ma and 43 Ma reveals that although the relative motion of an overriding plate margin is the dominant force effecting tectonic regime on the overriding plate margin, this can be overridden by extension caused by the underlying slab window. Mid-ocean ridge subduction can also affect the balance of global plate motions. A longstanding controversy in global tectonics concerns the ultimate driving forces that cause periodic plate reorganisations. I find strong evidence supporting the hypothesis that the plates themselves drive instabilities in the plate-mantle system rather than major mantle overturns being the driving mechanism. I find that rapid sub-parallel subduction of the Izanagi mid-ocean ridge and subsequent catastrophic slab break o_ likely precipitated a global plate reorganisation event that formed the Emperor-Hawaii bend, and the change in relative plate motion between Australia and Antarctica at approximately 50 Ma

Thesis (M.A.)--Ohio University, June, 2008. / Title from PDF t.p. Includes bibliographical references.

Thesis (Master of Business Administration)--Naval Postgraduate School, June 2009. / Thesis Advisor(s): San Miguel, Joseph G. "June 2009." Description based on title screen as viewed on July 14, 2009. Author(s) subject terms: software reuse, reuse, ASW software, sonar, fire control, APB, ARCI. Includes bibliographical references (p. 97-100). Also available in print.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 122-136).

Thesis (Ph. D.)--Oregon State University, 2005. / Printout. Includes map in pocket. Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2002. / "Joint Program in Oceanography/Applied Ocean Science and Engineering."--Cover. "June 2002." Funding was provided by NASA through grants NAG5-3264, NAG5-4806, NAG5-11113 and NAG5-9143 and by a National Defense Science and Engineering Graduate Fellowship. Includes bibliographical references (p. 221-243).

Thesis (Ph. D.) --Memorial University of Newfoundland, 1997. / Restricted until November 1998. Bibliography: leaves 220-236. Also available online.

Thesis (Ph.D.)--University of Western Australia, 2007.

Thesis (Ph. D.)--Texas A & M University, 1983. / Vita. Includes bibliographical references (leaves 110-120).