Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1984. / Microfiche copy available in Archives and Science. / Includes bibliographies. / by Paul Edward Speer. / Ph.D.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1984. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN. / Bibliography: leaves 232-235. / by Kenneth M. Tubman. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1984. / Microfiche copy available in Archives and Science. / One folded illustration in pocket attached to back cover. / Bibliography: leaves 40-41. / by Janine Commerford. / M.S.

Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2014. / Cataloged from PDF version of thesis. / Includes bibliographical references (page 33). / Hydraulic fracturing has fundamentally changed the oil and gas industry in the past 10 years. Bakersfield, California provides a unique case study because steam injection, a type of hydraulic fracturing, has been used there for more than 60 years. Seven companies, varying in size and strategy, use steam injection in California. Some of these companies use microseismic monitoring technologies to maximize production from hydrocarbon reservoirs. In this study, the effectiveness of microseismic monitoring to maximize production in California is explored. This is accomplished by comparing trends in oil and gas production volumes with each company's use of microseismic monitoring. This project found that operators that use microseismic most extensively have not achieved a competitive advantage over other operators. This means that substantial investments in monitoring research, installation and data interpretation have not paid off and may not be worthwhile. This result should help companies improve their current projects and shape future investment decisions. / by Ann M. Alampi. / S.B.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2009. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 93-101). / The roll of melt in deformation of the mantle is important for understanding mantle processes and evolution. The Beni Bousera Ultramafic Massif, northern Morocco, shows petrologic evidence that melt was an important part of its history. The massif, dominantly composed of spinel lherzolite with harzburgitic sections, has 10 to 100 meter scale zones which contain abundant pyroxenite dykes, dunite, harzburgite, and secondary lherzolite. These zones are interpreted as areas of focused melt percolation. Lattice preferred orientation (LPO) of olivine crystals from a sample transect across one of these zones was analyzed in comparison with LPO from the surrounding host lherzolite and harzburgite. The LPO from peridotites within the zone was slightly different from those outside the zone, and the LPO from the dunite analyzed was significantly different from the peridotites. Within the melt percolation zone, orientation of the olivine a-axis with respect to the mineral foliation indicates that strain increases towards the center of the zone and that shear sense changes across the zone. This suggests that focused melt flow can induce deformation in its host peridotite. / by Jessica R. Stanley. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1988. / Includes bibliographical references. / by Joseph R. Matarese. / M.S.

Thesis: Ph. D. in Climate Physics and Chemistry, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 155-163). / Observations and climate models show a pronounced land-ocean contrast in the responses of surface temperature and the hydrological cycle to global warming: Land temperatures increase more than ocean temperatures, low-level relative humidity increases over ocean but decreases over land, and the water cycle has a muted response over land in comparison to ocean regions at similar latitudes. A comprehensive physical understanding of these land-ocean contrasts has not been established, despite the robustness of the features and their importance for the regional and societal impacts of climate change. Here we investigate land-ocean contrasts in temperature, relative humidity, and precipitation minus evaporation (P - E) under climate change using both idealized and full-complexity models. As in previous studies, we find enhanced surface warming over land relative to the ocean at almost all latitudes. In the tropics and subtropics, the warming contrast is explained using a convective quasi-equilibrium (CQE) theory which assumes equal changes in equivalent potential temperature over land and ocean. As the CQE theory highlights, the warming contrast depends strongly on changes in relative humidity, particularly over land. The decreases in land relative humidity under warming can be understood using a conceptual model of moisture transport between the land and ocean boundary layers and the free troposphere. Changes in P - E over ocean are closely tied to the local surface-air temperature changes via a simple thermodynamic scaling; the so-called "rich-get-richer" mechanism. Over land, however, we show that the response has a smaller magnitude and deviates substantially from the thermodynamic scaling. We examine the reasons for this land-ocean contrast in the response of P - E by analyzing the atmospheric moisture budget. Horizontal gradients of surface temperature and relative humidity changes are found to be important over land, with changes in atmospheric circulation playing a secondary role outside the tropics. An extended thermodynamic scaling is introduced and is shown to capture the multimodel-mean response of P - E over land, and the physical mechanisms behind the extended scaling are discussed. / by Michael P. Byrne. / Ph. D. in Climate Physics and Chemistry

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2009. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Includes bibliographical references. / The sequence of events over the Neoproterozoic - Cambrian transition that led to the radiation of multicellular organisms has been an issue of debate for over a century. It is a critical interval in the history of life on Earth because it marks the first appearance of all extant animal phyla in the fossil record. We set out to improve understanding of environmental transitions during this key interval of Earth's history by studying chemical fossils (biomarkers) in Neoproterozoic to Cambrian aged sedimentary rocks and oils from Australia, Eastern Siberia and Oman. This thesis presents the distributions of steranes and other hydrocarbons through these various strata and the characterization of novel age and paleostratification biomarkers. Compound specific carbon isotopic data of n-alkanes and isoprenoids were also acquired and evaluated in the context of existing datasets with a focus on elucidating the processes responsible for anomalous trends. Consistent with current theory, our results indicate that there was a significant shift in the redox state the oceans and that this took place on a global scale. The biomarker and isotopic proxies we have measured help us further constrain the timing of this redox shift, and suggest a concomitant switch in the composition of marine photosynthetic communities, at termination of the Neoproterozoic Era. / by Amy Elizabeth Kelly. / Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2000. / Includes bibliographical references (p. 61-62). / For subduction to occur, plates must bend and slide past overriding plates along fault zones. This deformation is associated with significant energy dissipation, which changes the energy balance of mantle convection and influences the thermal history of the Earth. To parameterize these effects, a subduction zone was included in a small region of a finite element model for the mantle, which also features an asthenosphere and a mid-oceanic ridge. Velocity boundary conditions were imposed in the vicinity of the subduction. We present theoretical arguments for, and numerical illustrations of the fact that for most modes of deformation, the simple powerlaw relationship of parameterized convection Nu ~ Ra[beta] is not valid anymore, although it is still a good first order approximation. In the case of viscous bending dissipation and non-depth dependent brittle simple shear however, Nu ~ Ra[beta] does hold. [Beta] is less than the value of 1/3 predicted by standard boundary layer theory. For viscous energy dissipation, two different regimes of mantle convection can be considered, depending on the effective viscosity of the lithosphere: the "mobile lid" regime, and the "stagnant lid" regime. For brittle dissipation, the lithosphere strength is a function of yield stress which, when nearing a certain critical value, introduces a third regime, that of the "episodic overturning". Within the "mobile lid" regime, the plate velocities for models with a subduction zone governed by brittle behavior are far less dependent on the plate stress than those models with viscous deformation. This suggests that the plate motion is resisted by viscous stresses in the mantle. The "mobile lid" would be representative for mantle convection associated with plate tectonics, as we observe on Earth. A "stagnant lid" would be the case for the Moon or Mars, while Venus could experience the "episodic overturn" regime featuring cyclic and catastrophic brittle mobilization of a lithosphere with high friction coefficient. / by Pieter Vermeesch. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1990. / Archives copy lacks leaf 247. / 15 folded maps in pocket. / Includes bibliographical references (leaves 120-140). / by José Wilson Corrêa Rosa. / Ph.D.