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Showing 1 to 20 of 20 for “"Rift zone"”.
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Incipient continental rifting: insights from the Okavango Rift Zone, northwestern Botswana
… Model (SRTM DEM) data from the Okavango Rift Zone in northwest Botswana are used to map the distribution of rift and basement structures. The distribution of these structures provide useful insights into the early stages of continental rifting. The objectives of this study are (1) …
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Layered crustal and mantle structure and anisotropy beneath the Afar Depression and Malawi Rift Zone
… been acquired within the vicinity of continental rift zones, the mechanisms responsible for the breakup of stable continental lithosphere are ambiguous. Eastern Africa is host to the largest contemporary rift zone on Earth, and is thus the most prominent site with which to investigate the …
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Isotopic, geochemical, and geochronological constraints on the origin and evolution of Cenozoic volcanism, Baikal Rift Zone, Siberia
The Cenozoic Baikal Rift Zone, one of the world's major continental rifts, is expressed as an approximately 1800 km-long southwest-northeast oriented system situated along a suture between the Archean Siberian craton and younger Paleozoic fold belts. Oligocene to Recent age volcanic rocks and …
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Thermal structure, compensation mechanisms, and tectonics of actively-deforming continents : Baikal Rift Zone and large-scale overthrust and extensional terrains
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1992.
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Identification, Characterization and Analysis of Wrench Related Faulting in Southwestern Warren County, Kentucky
… that extends into Kentucky from the Reelfoot rift zone. The Rough Creek fault system bounds the northern arm of the Rough Creek Graben and trends northwest-southeast also extending from the Reelfoot rift zone. The Rough Creek fault system is related to the Shawneetown fault system in …
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Tectonic evolution of the Corinth Rift
… of extensional processes at continental rift zones provides important constraints on the underlying lithospheric deformation mechanisms, level of seismic hazard and location of likely hydrocarbon traps. The Corinth rift in central Greece is one of the few examples that has experienced a …
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Diverse Primitive Basalts from an Extensional Back-arc Setting: Fort Rock Volcanic Field, Oregon
… and extension from the Basin & Range continental rift zone. Hydrovolcanic eruptions created tuff rings/cones and maars, while conventional eruptions created cinder cones, and lava fields in the FRVF area. These landforms contain a diverse array of primitive basalts, with an Mg# (xMgO / (xMgO + …
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Magmatic processes at basaltic volcanoes: insights from the crystal cargo
… the plumbing system between the summit and East Rift Zone, with a focus on timescales of storage and transport. The first part investigates the melt geochemistry in terms of heterogeneity and volatile composition, and the second investigates the crystal cargo in terms of features of the …
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Receiver function investigations of mantle transition zone and crustal structure in East Africa and Northeast Asia
… crust, upper mantle, and the mantle transition zone (MTZ) are still controversial. The MTZ discontinuities beneath the study area are imaged by stacking an unprecedented volume of receiver functions (RFs). The normal MTZ thickness beneath the Western Branch of the EARS and Tanzania Craton …
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Surface Wave Inversion of the Upper Mantle Velocity Structure in the Ross Sea Region, Western Antarctica
… basins formed during Cretaceous to Paleogene rifting. Several seismic studies along the Transantarctic Mountains and Victoria Land Basin’s Terror Rift have shown a general pattern of fast seismic velocities in East Antarctica and slow seismic velocities in West Antarctica. This study focuses …
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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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Petrology and alteration in the core of the Bear Lodge Tertiary intrusive complex, Bear Lodge Mountains, Crook County, Wyoming
… carbonatite complexes along the East African rift zone. The Bear Lodge complex is similar to some of the East African complexes and is also feldspathized. The rocks are hypabyssal and represent an intermediate volcanic level.</p> <p>Rare earth elements are present, primarily in Th-RE veins and …
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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
… Basin. I inferred the AGM as a Precambrian rift zone composed of lower density granitic and metasedimentary rocks. Basement structure defines the limits of deep basinal areas that may host productive, thermally mature source rock kitchens controlled in part by strike-slip faults aligned with …
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The structure and seismicity of Icelandic rifts
… plate boundaries I have studied the oceanic rift in Iceland. Here the Mid Atlantic Ridge is anomalously elevated above sea level and thus easier to instrument. I have deployed and operated a dense network of seismometers in the remote volcanic highlands in central Iceland, and used the …
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Structural, stratigraphic and geochemical studies of the Horwood Peninsula - Gander Bay Area, Northeast Newfoundland /
… is located at NE Newfoundland in the Botwood Zone (Williams et a1., 1974) or in the Dunnage Zone (Williams, 1979) of the Central Mobile Belt of the Newfoundland Appalachians. The area is underlain by Middle Ordovician to possible Lower Silurian rocks of the Davidsville and Indian Islands …
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Evolution of tectonic and stratigraphic geometries in the Southern Outeniqua Basin
… break-up of Gondwana. Early Jurassic (170-150Ma) rifting between West and East Gondwana is proposed to have created weaknesses in the crust along the Southern African margin in a NNE-SSW orientation leading to the development of small rift basins and the deposition of syn-rift sediments. A series …
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Tephrostratigraphy, petrography, geochemistry, age and fossil record of the Ganigobis Shale Member and associated glaciomarine deposits of the Dwyka Group, Late Carboniferous, southern Africa
… could have been located in an intracontinental rift zone along the western margin of southern Africa which is indicated by north-south directed ice-flow directions in the Late Carboniferous. SHRIMP-based age determinations of juvenile magmatic zircons separated from the tuff beds allow a new …
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La Sicilia come regione pilota per la micro-zonazione del potenziale geotermico di bassa entalpia
… con importanti anomalie geotermiche, come le zone vulcaniche dell'Arco delle Isole Eolie, l'area etnea e la Rift Zone del Canale di Sicilia, aree che risultano quindi idonee allo sfruttamento risorse geotermiche di medio-alta entalpia. La modellazione termica sia su scala locale suggerisce …
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The petrogenesis and geochemistry of the Namaqualand olivine melilitite pipe cluster, western South Africa
… that caused the NBW lineament by triggering a zone of magmatism along a deep-seated zone of weakness in the lithospheric mantle between Southern Africa into the east African rift zone, however, more evidence would be needed to fully support this possibility.
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Rheological response to tectonic and volcanic deformation in Iceland
… (WVZ), Eastern (EVZ), and Northern Volcanic Zones (NVZ). These zones include 35 active volcanic systems and most of them are located on the plate boundaries. Often a volcanic system consists of a central volcano and an associated fissure swarm. Geothermal activities and Glacial Isostatic …