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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 20 of 27 for “"Continental Rifting"”.
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Incipient continental rifting: insights from the Okavango Rift Zone, northwestern Botswana
… provide useful insights into the early stages of continental rifting. The objectives of this study are (1) assessing the role of pre-existing structures on rift basin development, (2) characterizing the geometry of the nascent rift basins, (3) documenting fault growth and propagation patterns, and …
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Effects of Initial Thermal Structure on the Evolution of Continental Rifting
Continental rifting is a fundamental earth process that displays a wide variety of styles ranging from narrow to wide, symmetric and asymmetric, magmatic and amagmatic. The key conditions and processes that control the evolution of rifts remain enigmatic. Previous research suggests that the initial …
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Seismic imaging and thermal modeling of active continental rifting processes in the Salton Trough, Southern California
Continental rifting ultimately creates a deep accommodation space for sediment. When a major river flows into a late-stage rift, thick deltaic sediment can change the thermal regime and alter the mechanisms of extension and continental breakup. The Salton Trough, the northernmost rift segment of …
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A Geodynamic Investigation of Continental Rifting and Mantle Rheology: Madagascar and East African Rift case studies
Continental rifting is an important geodynamic process during which the Earth's outer-most rigid shell undergoes continuous stretching resulting in continental break-up and theformation of new oceanic basins. The East African Rift System, which has two continentalsegments comprising largely of the …
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A geological and geophysical study of the Tendaho Graben in the Afar Depression, Ethiopia: insights into transitional continental rifting
… features that can best be interpreted as a continental rift undergoing oceanization. This NW-trending extensional structure is ~50 km wide and it is confined within well-developed NW-trending boarder faults that deform the 2 km thick and ~ 2 Ma basaltic flows of the Afar Stratoids. The age …
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Geochemistry of dolerites from the Parana flood basalt province, southern Brazil
… dolerites was derived from a source in the subcontinental mantle. The-dolerites of Sao Paulo State are divisible into three magma types, which cannot be related either to one another, or to the flood basalts to the west by any simple petrogenetic process. The geochemical variation within …
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Petrology and geochemistry of pyroxenites in the Lanzo ultramafic massif, Northwestern Italy
… and more generally on the role of magmatic rifting and the rift-to-drift transition in ultraslow-spreading ridge environments. Two separate generations of pyroxenites have been distinguished. A young set of primitive Cr-diopside websterites of MORB affinity are related to melt infiltrations …
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Formation and evolution of the eastern Black Sea basin: constraints from wide-angle seismic data
Rifted continental margins and extensional basins, provide lasting records of the processes that occur during continental break-up and initial spreading. The eastern Black Sea (EBS) basin provides a good setting to study the development of continental margins, because of ongoing sedimentation …
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Tectonic and magmatic processes during extension in planetary lithospheres : rifting, spreading, delamination, and recycling on Earth and Venus
… systems. On Earth, the processes underpinning continental break-up are poorly understood despite decades of study. In this dissertation, I present a synthesis of numerical modeling, high resolution seismic experiments, and ophiolite geology to reveal how the mantle lithosphere controls the …
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Modelling the controls on melt generation during continental extension and breakup
Rifting is the process that leads to the formation of oceans. Rifting is the break up of<br/>continents, leading to the formation of new oceanic floor between the two continental<br/>plates. Although the concept of continental rifting is accepted within the scientific<br/>community, it is still …
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Petrogenesis and thermal history of the Kunlun Batholith, Northern Tibet
… along the Zangbo and Jinsha suture lines. Continental rifting was followed by a prolonged period of northward subduction of the Qiangtang Terrane beneath the Kunlun Terrane. This resulted in formation of the Permian batholith, and the massive Songban-Ganzi accretionary prism. Subduction …
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Tectonics of the West Iberia continental margin from seismic reflection data
Continental rifting is a fundamental component of the plate tectonic cycle. The West Iberia passive margin is a classic example of a nonvolcanic rifted margin. The West Iberia margin contains an enigmatic north-south ridge of serpentinized peridotite located within the ocean-continent transition. …
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DETRITAL-ZIRCON GEOCHRONOLOGIC PROVENANCE ANALYSES THAT TEST AND EXPAND THE EAST SIBERIA - WEST LAURENTIA RODINIA RECONSTRUCTION
… off in the latest Proterozoic due to successful continental rifting. Grenville sediments were cut off from SW Laurentia in the latest Proterozoic-Middle Cambrian either due to the development of an impediment between the orogen and the basin, or due to the transgression of the Cambrian Sea from …
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DETRITAL-ZIRCON GEOCHRONOLOGIC PROVENANCE ANALYSES THAT TEST AND EXPAND THE EAST SIBERIA - WEST LAURENTIA RODINIA RECONSTRUCTION
… off in the latest Proterozoic due to successful continental rifting. Grenville sediments were cut off from SW Laurentia in the latest Proterozoic-Middle Cambrian either due to the development of an impediment between the orogen and the basin, or due to the transgression of the Cambrian Sea from …
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Gravity Modeling, Seismic Stratigraphy, and Thermal Maturity Modeling of Hydrocarbons of the Permian Foreland Basin, USA, and the Sergipe-Alagoas Rifted-Passive Margin, Brazil
… Chapter 4, I define three domains of the rifted, continental crust in the Sergipe-Alagoas basin based on 2D seismic interpretations and 2D and 3D gravity models: 1) necked zone of continental crust; 2) hyper-extended zone of continental crust, and 3) the outer domain. The conjugate margin in …
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Mesozoic Rift Evolution and Crustal Structure of the Gulf of Mexico Basin from Integration of Multiple Geological and Geophysical Datasets
… Triassic-early Jurassic, northwest-to-southeast rifting to late Jurassic north-south rifting. In Chapter 3, I test two GOM opening models by integrating reflection data, refraction data, gravity data, and well data from the greater GOM area. Inversion of gravity data for crustal thickness used …
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Heterogeneous Strain Distribution & the Effects of High Frequency Climate Change on the Evolution of Early-Stage Rift Systems: Case Studies from Lakes Tanganyika and Malawi (Nyasa), East Africa
… of the earth’s crust through the formation of continental rift basins is a fundamental aspect of plate-tectonics and the first step that ultimately leads to plate-spreading, new continent formation, and the creation of ocean basins. Within continental rifts, processes associated with …
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Biological diversity in Icelandic groundwater fissures
… ridge where bedrock cracks as a result of continental rifting. In some areas fissures penetrate the aquifer and expose the groundwater within the bedrock. The main objective of the study was to measure the biological diversity in groundwater fissures in Iceland. A large part of the …
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Examining the past to prepare for the future: Quaternary magma storage in the Main Ethiopian Rift and implications for volcanic hazard and resource potential
… settings, we still know relatively little about continental rift volcanism. The Main Ethiopian Rift (MER) is part of the larger East African Rift system, the archetypal example of continental rifting on our planet. Comprehensive geochemical datasets, including new whole-rock, glass (matrix glass …
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EVOLUTION OF THE EASTERN ALPS FROM THE PALEOZOIC ONWARD: CONSTRAINTS AND INSIGHTS FROM THE (ULTRA)BASIC ECLOGITIC COMPLEX OF MILCHENKAR ÖTZTAL-STUBAI COMPLEX (EASTERN ALPS, TYROL, AUSTRIA)
… of garnet stability, and the intrusion in continental crust in an extensional context, with some similiarities to the Oligocenic Red Sea rift. Additionally, the relatively alkalic nature of the melt suggested by mineral chemistry and whole rock compositions is consistent with the inferred …
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