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The influence of ridge geometry at the ultraslow-spreading Southwest Indian Ridge (9⁰-25⁰E) : basalt composition sensitivity to variations in source and process
(Massachusetts Institute of Technology, 2006)
Between 90-25° E on the ultraslow-spreading Southwest Indian Ridge lie two sharply contrasting supersegments. One 630 km long supersegment erupts N-MORB that is progressively enriched in incompatible element concentrations ...
Magmatism and dynamics of continental breakup in the presence of a mantle plume
(Massachusetts Institute of Technology, 2000)
This thesis studies the dynamics of mantle melting during continental breakups by geophysical, geochemical, and numerical analyses. The first part focuses on the mantle melting and crustal accretion processes during the ...
Gulf stream temperature, salinity and transport during the last millennium
(Massachusetts Institute of Technology, 2006)
Benthic and planktonic foraminiferal [delta]18O ([delta 18Oc) from a suite of well-dated, high-resolution cores spanning the depth and width of the Straits of Florida reveal significant changes in Gulf Stream cross-current ...
Geobiology of marine magnetotactic bacteria
(Massachusetts Institute of Technology, 2006)
Magnetotactic bacteria (MTB) biomineralize intracellular membrane-bound crystals of magnetite (Fe3O4) or greigite (Fe3S4), and are abundant in the suboxic to anoxic zones of stratified marine environments worldwide. Their ...
Relating behavioral context to acoustic parameters of bottlenose dolphin (Tursiops truncatus) vocalizations
(Massachusetts Institute of Technology, 2001)
This thesis presents methods to analyze the function of vocalizations of the bottlenose dolphin, Tursiops truncatus. The thesis uses the social interaction as the basic unit of analysis, and maintains a deliberate focus ...
The role of denitrification in the nitrogen cycle of New England salt marshes
(Massachusetts Institute of Technology, 2002)
I used direct measurements of nitrogen gas (N₂ fluxes and a ¹⁵N stable isotope tracer to determine the contribution of denitrification to salt marsh sediment N cycling. Denitrification in salt marsh tidal creekbottoms is ...
Interactions between mantle plumes and mid-ocean ridges : constraints from geophysics, geochemistry, and geodynamical modeling
(Massachusetts Institute of Technology, 2001)
This thesis studies interactions between mid-ocean ridges and mantle plumes using geophysics, geochemistry, and geodynamical modeling. Chapter 1 investigates the effects of the Marion and Bouvet hotspots on the ultra-slow ...
Zinc and cadmium in benthic foraminifera as tracers of ocean paleochemistry
(Massachusetts Institute of Technology, 2000)
Benthic foraminiferal δ13C, Cd/Ca, and Ba/Ca are important tools for reconstructing nutrient distributions, and thus ocean circulation, on glacial-interglacial timescales. However, each tracer has its own "artifacts" that ...
Mechanisms of turbulent mixing in the Continental Shelf bottom boundary layer
(Massachusetts Institute of Technology, 2000)
The bottom boundary layer is an important dynamical region of shallow water flows. In this thesis, the problem of turbulent mixing in the coastal bottom boundary layer is investigated with a unique set of field measurements ...
The evolution of lithospheric deformation and crustal structure from continental margins to oceanic spreading centers
(Massachusetts Institute of Technology, 2002)
This thesis investigates the evolution of lithospheric deformation and crustal structure from continental margins to mid-ocean ridges. The first part (Ch. 2) examines the style of segmentation along the U.S. East Coast ...