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Showing 1 to 20 of 32 for “"Continental rift"”.
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Characterization of a volcanically impacted, overfilled continental rift basin within the southeastern Jemez Mountains, New Mexico
Volcanically impacted continental rift basins that experience coeval subsidence and volcanism challenge the conventional sedimentation models for continental rift basins. A field study was undertaken at the eastern margin of Bearhead basin within the southeastern Jemez volcanic field of north …
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Exhumation, rift-flank uplift, and the thermal evolution of the Rwenzori Mountains determined by combined (U-Th)/He and U-Pb thermochronometry
… represent an extreme example of basement rift-flank uplift in the western branch of the East African Rift, a phenomenon common throughout the East African Rift System and characteristic of continental rift systems in general. A thermochronologic study combining (U-Th)/He and U-Pb analysis …
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Understanding uplift of the Ethiopian Plateau from longitudinal profile analysis of the Blue Nile drainage system
… regions on Earth that is situated in continental rift zones. About 1.6 km deep gorge of the Nile was carved by the Blue Nile River on the Ethiopian Plateau, as the plateau has been experiencing continuous uplift and exhumation in the Cenozoic. Here, we used quantitative analysis of …
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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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The age, stratigraphy, and tectonic provenance of clastic deposits in the western Bikou terrane, southwestern Qinling Mountains, China
… theories ranging from subduction arc to continental rift; The southeastern portion of the Bikou terrane is composed of a metamorphosed volcanic arc with minor marine volcaniclastic sediments, known as the Bikou Group, previously dated by SHRIMP U-Pb zircon and conventional U-Pb as Late …
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Towards a model of the Cenozoic tectonic development of New Zealand
… during the early Miocene, about 23 My B.P. (2) A continental rift system developed through western New Zealand during the Paleogene. (3) Northeast of the Alpine Fault the relative plate motion was expressed as a combination of brittle and ductile shearing that formed a recurved arc. (4) There has …
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Diverse Primitive Basalts from an Extensional Back-arc Setting: Fort Rock Volcanic Field, Oregon
… Newberry, 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 / …
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The crustal structure and subsidence history of aseismic ridges and mid-plate island chains
… convection studies as well as the origin of continental rift systems.
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Depositional conditions, stratigraphic evolution, and allo- and autogenic controls of lower Permian non-marine carbonate rocks, Lucaogou low-order cycle, Bogda Mountains, NW china
… low-order cycle in the greater Turpan-Junggar continental rift basin, NW China. The depositional environments of ten carbonate lithofacies in the Tarlong-Taodonggou half graben and the Zhaobishan section were interpreted. Allo- and autogenic factors were identified. They controlled …
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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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Layered crustal and mantle structure and anisotropy beneath the Afar Depression and Malawi Rift Zone
… sets have 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 …
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Origin and Emplacement Mechanisms of the Slieve Gullion Ring Dyke Complex, Ireland
… of Ewart (1982). This suggests a cratonic or continental rift environment which supports that this igneous complex is related to the opening of the Atlantic Ocean. The geochemistry results and observations of the thin sections for the rafts of basalt found within the Forkill Quarry both …
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The geochemistry of fluid processes in the eastern branch of the East African Rift System
The East African Rift System is the world's major continental rift. While much geophysical and petrological attention has been paid to it, at least in the eastern branch ("Eastern Rift"), comparatively little research has been carried out into the geochemistry of rift fluids, despite the potential …
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Partitioning of fluid flow along faults and fractures in the Bristol Channel Basin: implications for low carbon geoscience projects in SW England
The Bristol Channel Basin (BCB) is a Mesozoic continental rift basin and an important<br/>analogue for offshore reservoirs. Previous studies have used relative cross-cutting<br/>relationships and correlations with adjacent sedimentary basins to constrain its<br/>development. For the first time, …
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Investigating the Kinematics and Dynamics of Strain Localization in the Northern Western Branch of the East African Rift System
Continental rifts are thought to be formed by repeated episodes of magmatism, reactivation of pre-existing structures, or a combination of both. Continental rifts are evidence of a divergent plate boundary, where tectonic plates are breaking apart. The northern Western Branch of the East African …
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Geology, Petrology, and Tectonic Setting of the Mafic Rocks of the 1480 MA Old Granite-Rhyolite Terrane of Missouri, USA
… Between 1400 to 1200 Ma ago, an incipient continental rift may have formed along the axis of the 1500 to 1400 Ma old magmatic belt. Mafic magma emplaced during the rifting event possibly included the Skrainka Mafic Group of Missouri, the Harp dikes and Seal Lake Group of Labrador, and some …
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Oxygen and radiogenic isotope constraints on the generation of coexisting silica-undersaturated and oversaturated felsic magmas of the Ditrau Alkaline Massif (Romania)
… igneous complex (~200-230 Ma) was generated in a continental rift environment. This study has investigated the relationship between the silica-undersaturated and oversaturated Ditrău rocks based on oxygen, Sr, Nd and Pb isotope data. Different models have been proposed previously to explain the …
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Thermo-tectonic record of hyperextension, structural inversion, and foreland basin evolution of the eastern and central Pyrenees
Direct constraints on processes associated with rifting and mantle exhumation are necessary to understand the thermal and structural evolution of continental rift systems, and the role of pre-existing crustal architecture on orogenesis and foreland basin development. This work constrains the Early …
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Nature and Potential Origins of the Low-Rate Tectonics of the Hauraki Rift and North-Western New Zealand: A Geophysical Investigation
… relative to Australia) and home to the Hauraki Rift, N-S trending, 250+ km long and 25 km wide on-shore/off-shore continental rift 40 km east of Auckland City and oblique to the Hikurangi subduction margin. A three-year 40+ station campaign GNSS geodetic survey was done incorporating previously …
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Tectono-hydrothermal evolution of the Neoarchean Abitibi greenstone belt, Canada
… they are most consistent with sedimentation in continental rift or strike slip basins. The alluvial-fluvial conglomerates and sandstones of the Timiskaming assemblage contain abundant quartz clasts and igneous clasts containing quartz veins. To better constrain the origin of these clasts, …
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