نتایج جستجو برای: batholith
تعداد نتایج: 422 فیلتر نتایج به سال:
We present an original geological map of the north-eastern Serre Batholith (southern Italy), together with new field and petrographic data its main five granitoid units. Our study provides overall picture a c. 13-thick floor-to-roof batholith exposure, focusing on relationships between magmatic units, which were sequentially emplaced at depth from 23 to 6 km, in time interval 297 Ma 292 Ma. Ind...
We present evidence for a thick ( 100 km) sequence of cogenetic rocks which make up the root of the Sierra Nevada batholith of California. The Sierran magmatism produced tonalitic and granodioritic magmas which reside in the Sierra Nevada upperto midcrust, as well as deep eclogite facies crust/upper mantle ma®c±ultrama®c cumulates. Samples of the ma®c±ultrama®c sequence are preserved as xenolit...
The calc-silicate xenoliths, within the Shir-Kuh batholith are characterized by melilite, garnet, vesuvianite, and wollastonite mineral assemblage. On the basis of paragenetic relations, prograde and retrograde metamorphism are involved in the formation of these minerals. Melilite, wollastonite and diopside formed during progressive metamorphism which was accompanied by thermal peak shocking a...
Abstract Accurate reconstruction of the Late Cretaceous paleogeography and tectonic evolution western North American Cordilleran margin is required to resolve long-standing debate over proposed large-scale, orogen-parallel terrane translation. The Nanaimo Basin (British Columbia, Canada) contains a high-fidelity record orogenic exhumation basin subsidence in southwestern Canadian Cordillera tha...
Ellipsoidal huge granitoidic batholiths of Zahedan, with NW-SE trending, located in south of this city which is intruded in low metamorphosed Eocene flysches (eastern Iran flysch zone). This batholith has two compositional terms: an extensive intermediate-acid term includes diorite - granodiorite with igneous source (I- type origin) and a low extent crustal and hybrid origin acidic term (H-type...
The Peninsular Ranges batholith of southern California and Baja California, México, is well recognized as a prime example of an I-type Cretaceous batholith. Often overlooked, however, is a volumetrically signiÞ cant amount of pre-Cretaceous gneissic granite in the axial zone of the batholith. New U-Pb zircon age data conÞ rm that the metaluminous and peraluminous plutonic bodies were emplaced d...
[1] Lateral variations of the crustal structure in southern California are determined from receiver function (RF) studies using data from the Southern California Seismic Network broadband stations and Los Angeles Regional Seismic Experiment surveys. The results include crustal thickness estimates at the stations themselves, and where possible, cross sections are drawn. The large-scale Moho dept...
Oxygen isotope ratios of zircon (Zc) from intrusives exposed in the Tehachapi Mountains, southern California, reveal large inputs of high-dO supracrustal contaminant into gabbroic and tonalitic magmas deep (N30 km) in the Cretaceous Sierra Nevada batholith. High dO(Zc) values (7.8F0.7x) predominate in the deep parts of the batholith, but lower values (6.1F0.9x) occur in shallower parts. This in...
The Jura-Cretaceous Peninsular Ranges batholith (PRb) of southern and Baja California is a remarkable example of a zoned batholith containing distinct oceanic (western) and continental (eastern) basements. The transition between these basements is marked by a crustal-scale boundary along which distinct volcanosedimentary, structural, and metamorphic histories evolved during Mesozoic orogenesis....
The Altiplano-Puna Magma Body (APMB) in the Central Andes is the largest imaged magma reservoir on Earth, and is located within the second highest orogenic plateau on Earth, the Altiplano-Puna. Although the APMB is a first-order geologic feature similar to the Sierra Nevada batholith, its role in the surface uplift history of the Central Andes remains uncertain. Here we show that a long-wavelen...
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