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Evaluating mantle and crustal processes using isotope geochemistry
(Massachusetts Institute of Technology, 2000)
Geochemical studies are fundamental for understanding how the dynamic Earth works and evolves. These studies place constraints on the composition, formation, age, distribution, evolution and scales of geochemically distinct ...
Chemical characterization of dissolved organic matter (DOM) in seawater : structure, cycling, and the role of biology
(Massachusetts Institute of Technology, 2005)
The goal of this thesis is to investigate three different areas relating to the characterization of dissolved organic matter (DOM): further determination of the chemical compounds present in high molecular weight DOM ...
Experimental and seismological constraints on the rheology, evolution, and alteration of the lithosphere at oceanic spreading centers
(Massachusetts Institute of Technology, 2007)
Oceanic spreading centers are sites of magmatic, tectonic, and hydrothermal processes. In this thesis I present experimental and seismological constraints on the evolution of these complex regions of focused crustal accretion ...
Radium isotopes as tracers of coastal circulation pathways in the Mid-Atlantic Blight
(Massachusetts Institute of Technology, 2003)
Pathways of exchange between the shelf and slope in the Mid-Atlantic Bight were investigated using a combination of radiochemical tracer and hydrographic measurements. The motivation was to provide evidence of transport ...
Geochemical characerization of endmember mantle components
(Massachusetts Institute of Technology, 2005)
This thesis uses trace elements and radiogenic isotope tracers to define elemental abundances in reservoirs of the Earth's mantle, including EM2 (the Enriched Mantle 2), as seen in the Samoan hotspot track, and DMM (the ...
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 ...
Absarokites from the Western Mexican Volcanic Belt : constraints on mantle wedge conditions
(Massachusetts Institute of Technology, 2002)
We have investigated the near liquidus phase relations of a primitive absarokite from the Mascota region in Western Mexico. Sample M. 102 was chosen because it has high MgO contents, a high Mg# and Fo90 olivine phenocrysts, ...
Phosphate-mineral interactions and potential consequences for nutrient cycling
(Massachusetts Institute of Technology, 2008)
Biogeochemical cycling of phosphate is a key component in the overall production rate of coastal ecosystems. Mineral phases in the near-shore sediments play a significant role in the return of phosphate remineralized in ...
Slip on ridge transform faults : insights from earthquakes and laboratory experiments
(Massachusetts Institute of Technology, 2005)
The relatively simple tectonic environment of mid-ocean ridge transform fault (RTF) seismicity provides a unique opportunity for investigation of earthquake and faulting processes. We develop a scaling model that is complete ...
Organic phosphorus in marine sediments : chemical structure, diagenetic alteration, and mechanisms of preservation
(Massachusetts Institute of Technology, 2000)
Phosphorus, an essential nutrient, is removed from the oceans only through burial with marine sediments. Organic phosphorus (Prog) constitutes an important fraction (ca. 25%) of total-P in marine sediments. However, given ...