Global ETD Search
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Showing 1 to 8 of 8 for “"arc volcanism"”.
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Sedimentological constraints on Precambrian crustal evolution in northern New Mexico
… This juvenile crust developed as a magmatic arc complex and represents an early period of crustal instability. Between 1,755 and 1,700 m.y., the volcanogenic sequence was intruded by voluminous, coeval granodiorites and tonalites which stabilized the early crust. Unconformably overlying the …
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Geology of the central Moresby Island region, Queen Charlotte Islands, (Haida Gwaii) British Columbia
… Formation and Kunga Group, Middle Jurassic arc volcanic rocks of the Yakoun Group, marine sedimentary rocks of the Longarm Formation and Queen Charlotte Group, and Tertiary volcanic rocks. The Karmutsen Formation and Kunga Group rocks exposed in central Moresby Island formed during a …
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The genesis of ‘giant’ copper-zinc-gold-silver volcanogenic massive sulphide deposits at Tambogrande, Perú : age, tectonic setting, paleomorphology, lithogeochemistry, and radiogenic isotopes
… massive sulphide deposits known. Limited research has been done on these deposits, hence the ore forming setting in which they developed and the key criteria that permitted such anomalous accumulation of base-metal sulphides are not understood. Based on field relationships in the host volcanic …
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Igneous life cycles: geochemistry of magma from mantle to surface and back again
… processes in this life cycle. Continental arc volcanism generates a wide diversity of magma compositions, but the tempos of compositional variation are unclear. Here, we investigate a 7-million year record of volcanic ash layers in the Cretaceous Eagle Ford Group to investigate temporal …
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From the Foreland and Retroarc Thrust Belts to the Mantle Transition Zone: First Multi-Scale Retrodeformable Transect of the Active 90 mm/yr Taiwan Arc-Continent Collision
… retrodeformable transects of the Taiwan arc-continent collision. Chapter 1 presents reprocessed marine seismic reflection profiles of the retroarc thrust belt near Chimei Canyon offshore eastern Taiwan, which is one of the largest submarine canyons around Taiwan and results from the <1 Ma …
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Petrology and geochemistry of Sangeang Api and recent volcanism in the Sumbawa-Flores sector of the Sunda Arc: the response of along-arc geochemistry to subduction processes.
… Kuta) from adjacent sectors of the eastern Sunda Arc, Indonesia. Sangeang Api erupts co-magmatic suites of lavas and cumulate xenoliths. Lavas are ne-normative, silica-undersaturated, volatile-rich, shoshonitic basalts to basaltic-trachyandesites. They have trace-element compositions typical of …
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Boron as a tracer for material transfer in subduction zones
… Vulkanite der vulkanischen Front und der Back-arc Region der Zentralen Vulkanischen Zone in den Anden weisen eine weite Spannbreite von delta 11B Werten (+4 bis –7 ‰) and Borkonzentrationen (6 bis 60 ppm) auf. Die positiven delta 11B Werte der Vulkanite der vulkanischen Front …