Results 121 to 130 of about 199 (173)

Crustal generation of the Himalayan leucogranites

Tectonophysics, 1987
Abstract Detailed studies of the Himalayan two-mica leucogranites, such as the Manaslu pluton, indicate that they have very uniform mineralogical, petrological and structural characteristics. One can relate their occurrence to the thickest zones of the underlying Tibetan Slab.
P. Le Fort, M. Cuney, C. Deniel, C. France-Lanord, S.M.F. Sheppard, B.N. Upreti, P. Vidal   +6 more
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Himalayan Leucogranites: A Geochemical Perspective

Elements
The geochemical characterization of Himalayan leucogranites offers important insights into both their petrogenesis and Himalayan orogenic processes. Himalayan leucogranites are characterized by strongly peraluminous compositions that are comparable to melts derived from anatexis of sedimentary rocks.
Ze-Zhou Wang, Fang-Zhen Teng, Lingsen Zeng, Zhi-Chao Liu   +3 more
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Petrogenesis of leucogranites in collisional orogens

Geological Society, London, Special Publications, 2019
Abstract Leucogranites are a characteristic feature of collisional orogens. Their generation is intimately related to crustal thickening and the active deformation and metamorphism of metapelites. Data from Proterozoic to present day orogenic belts show that collisional leucogranites (CLGs) are peraluminous, with muscovite ...
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Himalayan Leucogranites: Petrogenesis and Significance

Elements
Himalayan leucogranites crop out intermittently over 2000 km along the crest of the world’s youngest and largest mountain range. They are derived from partial melting of continental crust during a classic continental collisional orogeny. Studies of these leucogranites have significantly advanced knowledge of crustal anatexis, felsic magmatic ...
Fang-Zhen Teng, Fu-Yuan Wu
openaire   +1 more source

Lithogeochemical exploration for uranium in leucogranites

Journal of Geochemical Exploration, 1989
Abstract In certain leucogranitic massifs in France and Spain, anomalies of uranium that extend for kilometers have been observed in rocks close to uranium deposits. Some of these anomalies were used to direct a reconnaissance survey which led to the discovery of a small blind deposit.
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JURASSIC LEUCOGRANITE-GRANITE FORMATION IN ALTAI

Russian Geology and Geophysics, 1991
A Middle-Mesozoic (Jurassic) leucogranite-granite formation, 180–200 Ma of age, has been recognized in Rudny and Gorny Altai on the basis of U–Pb geochronological dating, analysis of petrochemical data and metallogenic characteristics. In adjacent geostructural environments, granitoid massifs differ in completeness of manifestation of granite and ...
M. S. Kozlov, V. A. Khalilov, N. V. Stasenko, V. I. Timkin   +3 more
openaire   +1 more source

Himalayan Leucogranites: Field Relationships and Tectonics

Elements
Himalayan peraluminous leucogranites were derived from in-situ melting of sillimanite + K-feldspar-bearing pelite-migmatite, and were transported via layer-parallel sill complexes and cross-cutting dykes to feed giant sills up to 5 km thick. Partially melted Himalayan middle crust was extruded southwards between two large-scale, north-dipping ...
Mike Searle, John Cottle
openaire   +1 more source

Leucogranites of the Himalaya/Karakoram: implications for magmatic evolution within collisional belts and the study of collision-related leucogranite petrogenesis

Journal of Volcanology and Geothermal Research, 1990
Abstract Two types of leucogranite have been identified in a collisional setting in the Himalaya. Type-a (e.g., Manaslu, High Himalaya) are syn-tectonic crustal melts related to “hot over cold” thrusting and subsequent fluid fluxing. Type-b (e.g., Baltoro, Karakoram) is related to lower crustal melting during/following crustal thickening and thermal ...
Mark B. Crawford, Brian F. Windley
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Himalayan Leucogranites: A Minimal Role in Deformation

Elements
A popular model of Himalayan metamorphic and structural evolution argues that partial melting of deeply buried rocks triggered crustal weakening, ductile flow, orogenic collapse, and genesis of leucogranites. Here, we review the origins and evolution of partial melts and leucogranites to demonstrate that they are largely incidental to deformation ...
Matthew J. Kohn, Sean P. Long, T. Mark Harrison   +2 more
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Leucogranites and the Time of Extension in the East Greenland Caledonides

The Journal of Geology, 2005
Abstract Leucogranites provide timing estimates for deformation, particularly extension, in many orogens. On this basis, the time of extension in the East Greenland Caledonides has been estimated at 420–430 Ma. U‐Pb SHRIMP (sensitive, high‐resolution ion‐microprobe) analysis of zircon and monazite from selected leucogranites was undertaken to establish
Jane A. Gilotti, William C. McClelland
openaire   +1 more source