Cretaceous crustal structure and metamorphism in the hinterland of the Sevier thrust belt, western US Cordillera

Journal Article · Sun Jan 01 00:00:00 EST 1989 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1989)017<0059:CCSAMI>2.3.CO;2· OSTI ID:7000823

Miller, E L; Gans, P B ^[1]

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1. Stanford Univ., CA (USA)

Combined structural and geochronologic studies to the west of the Sevier belt at lat 39{degree}-40{degree}N indicate that peak metamorphism of the upper 15 km of crust occurred during the Late Cretaceous (70-90 Ma), overlapping in time with the intrusion of muscovite-bearing granites and pegmatites. Metamorphism was accompanied by penetrative deformation (top-to-the-east layer-parallel shear); both were localized at the currently exposed structural levels, resulting in impressive vertical and lateral strain gradients and T{sub max} gradients of > 50 C/km. Inception of thrust faulting in the Sevier belt may have predated peak metamorphism and intrusion of granites in the hinterland by 10-15 m.y., but it continued during and ended simultaneously with the end of metamorphism at about 70 Ma. The rise of muscovite-bearing granites and hot fluids, generated by metamorphism and crustal anatexis at greater depth, provides and explanation for the observed localized metamorphism and deformation at relatively high structural levels.

• OSTI ID: 7000823
• Journal Information: Geology; (USA), Vol. 17:1; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
WESTERN US OVERTHRUST BELT
METAMORPHISM
CRETACEOUS PERIOD
DEFORMATION
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC STRUCTURES
GEOLOGY
GRANITES
NEVADA
TEMPERATURE GRADIENTS
UTAH
FEDERAL REGION IX
FEDERAL REGION VIII
GEOLOGIC AGES
GEOLOGIC FRACTURES
IGNEOUS ROCKS
MESOZOIC ERA
NORTH AMERICA
PLUTONIC ROCKS
ROCKS
USA
580000* - Geosciences