Granite generation and rapid unroofing related to strike-slip faulting, Aysén, Chile

Francisco Hervé, Robert J. Pankhurst, Robert Drake, Myrl E. Beck, Constantino Mpodozis

Resultado de la investigación: Contribución a una revistaArtículo

31 Citas (Scopus)

Resumen

A stock of biotite-muscovite-garnet leucogranite crops out in the lower course of Río Cisnes as an unusual minor lithology within the predominantly dioritic to tonalitic North Patagonian Batholith. Foliated and unfoliated varieties are present-the former are nearer to the main lineament of the Liquiñe-Ofqui Fault Zone (LOFZ). Two-feldspar thermometry indicates equilibration temperatures above 600°C, for pressures probably not over 3 kbar, as suggested by the Mn-rich garnet composition. A Rb-Sr whole-rock isochron age of 9.6 ± 0.4 Ma (1σ error) probably indicates the time of magma crystallization. 40Ar-39Ar ages of 6.6 ± 0.3 Ma on muscovite and 5.5 ± 0.4 Ma on biotite are cooling ages from which a moderate average uplift/denudation rate (∼ 1 mm/yr) may be calculated. Paucity of occurrence, distribution close to the LOFZ and a near minimum-melt composition all suggest that the leucogranite magma was derived by partial melting of the lower crust, perhaps by decompression melting at a time when uplift/denudation rates were high (4 mm/yr or more are required). Regional evidence for rapid Holocene uplift in the immediate vicinity of the LOFZ substantiates the feasibility of the proposed petrogenetic model, which may be valid in other strike-slip orogenic environments.

Idioma originalInglés
Páginas (desde-hasta)375-386
Número de páginas12
PublicaciónEarth and Planetary Science Letters
Volumen120
N.º3-4
DOI
EstadoPublicada - 1 ene 1993

Áreas temáticas de ASJC Scopus

  • Ciencias planetarias y de la Tierra (miscelánea)
  • Geoquímica y petrología
  • Geofísica
  • Ciencias planetarias y de la Tierra (todo)
  • Ciencias ambientales (todo)

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