Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"Convergent margins"”.
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Thin-skinned deformation and plate driving forces associated with convergent margins
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1983.
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Crustal structure of rifted and convergent margins : the U.S. East Coast and Aleutian margins
… modify continental crust occur at continental margins, but recently has the scientific community acquired the necessary intrumentation to image crustal structure across margins in detail. In this thesis we investigate the crustal structure across the U.S. East Coast rifted margin and the …
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Crustal structure of rifted and convergent margins : the U.S. east coast and Aleutian margins
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1997.
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Why are there no low-δ18O magmas In convergent margins? A case of the Central Andes, Northern Chile
It has long been thought that low-δ 18O magmas (<5.7‰) are only found in extensional tectonic settings. Low-δ 18O magmas are rare, worldwide, especially in subduction zone settings. The main objective of this study was to conduct a search for low-δ 18O magmas in the Central Volcanic Zone (CVZ) of …
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From the Appalachians to the Alps: Constraints on the Timing, Duration, and Conditions of Metamorphism at Convergent Margins
The timing, duration, and pressure-temperature (P-T) conditions of metamorphism provide a direct record of the physical and chemical evolution of the crust and inform our knowledge and understanding of plate tectonics. The characteristic timescales and length-scales of metamorphism vary by orders …
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Geochemical Constraints of Porphyry Cu Deposits-Forming Magmas in Sonora, Mexico
… linked to the magmatic and tectonic evolution of convergent margins (Sillitoe, 2010). While the metallogenic characteristics of PCDs have been well-studied, the petrological and geochemical processes that govern magma fertility, essential prerequisites for PCD formation, remain less well …
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Effects Of Subduction History On Mantle Convection: Implications For True Polar Wander And Dynamic Topography
… of oceanic crust into the mantle along convergent margins; this process of recycling Earth materials destroys the geological data used to reconstruct plate history. To reconcile the long-debated subduction history of the circum-Pacific, this study implements two contrasted plate …
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Stratigraphic response to Cordilleran processes along the south central Andean margin
Subduction zones along convergent plate margins are fundamental components of Earth systems that link mountain building, magmatism, lithospheric dynamics, surface processes, and climate-carbon cycles. Resolving the feedbacks and relationships among these components has been a longstanding challenge …
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Fluid-mobile element cycling (halogens, boron, lithium) and sourcing through the Costa Rican convergent margin
The source of fluids in convergent margins can be traced using fluid-mobile elements such as Cl, Br, I, B, and Li. However, previous studies have often overlooked the forearc. Describing fluid loss from subducting oceanic crust to the forearc is difficult for several reasons including differences …
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New Constraints For Convergent Margin Plate Tectonic Reconstructions From Imaged And Predicted Mantle Structure
… plate model uncertainties can be traced to convergent margins, where tectonic plates are lost due to subduction. Our aim is to develop new, non-traditional constraints for convergent margin plate reconstructions from imaged and predicted mantle structure using seismic tomography and forward …
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An Investigation of the Geochemistry and Hydrogeology of the Queen Charlotte Fault
… fluids and plate boundary fault systems at convergent margins, yet comparatively little is known about the hydrogeology of submerged transform boundaries. Following the 2012 M7.8 earthquake off western Haida Gwaii, an international scientific partnership was established between US and …
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Modelling Viscous Flow and Elastic Deformation in Fold-Thrust Belts and Magmatic Intrusions
… of one another. Fold-thrust belts are formed at convergent margins, where accretion of weak sediments to the front of the overriding plate results in continued flexural subsidence of the underthrusting plate. In this dissertation I build a new dynamic model to investigate both the role of the …
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Magmatic and volcanic processing of volatile and chalcophile elements
… hydrous oxidised calc-alkaline arc magmas at convergent margins. It is not uncommon for these deposits to generate other critical element byproducts like selenium, tellurium, and bismuth, which in the current economic climate also face surging demands. Despite widespread recognition of the …
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Geochemical fractionation during melting of sulfide and sulfate bearing mantle lithologies
… cycle is connected to the deep sulfur cycle at convergent margins, where, crust and oceanic lithospheric mantle subducts beneath an overriding plate and transporting sulfur and other materials from the surface to the deep Earth. A part of the subducted sulfur gets released from the subducting …
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Numerische Simulation der Kohlenwasserstoffgenese an der Subduktionszone vor Costa Rica
… Therefore oil discoveries cannot be expected at convergent margins with high subduction velocities, at least not in the subducting plate. Gas discoveries are possible, especially if the hanging wall rocks are of higher porosity and permeability. The patchy distribution of BSRs within the 3D box …
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Magmatic volatiles at rifts and arcs: Sources and fractionation effects
… from surface reservoirs through subduction at convergent margins. Melts generated in the mantle carry dissolved volatiles from depth and upon decompression exsolve a fluid or vapour phase. These volatiles drive explosive eruptions, change climate, and form economic metal deposits. Thus, the …