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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 68 (1984)

Issue: 7. (July)

First Page: 937

Last Page: 937

Title: Effects of Overthrusting on Triassic Shelf Strata, East Range, Nevada: ABSTRACT

Author(s): M. W. Elison, R. C. Speed


Triassic shelf strata exposed in the East Range of north-central Nevada are overthrust from east to west by lower Paleozoic rocks, originally of the Roberts Mountain allochthon, and overthrust from west to east, along the Fencemaker thrust, by imbricated basinal turbidites and related deposits dated as Norian. Analysis of fabric elements of the shelf rocks indicates that early deformation was west verging, affirming an affinity to the predominantly west-verging Winnemucca fold and thrust belt.

Autochthonous or para-autochthonous shelf rocks consist of deltaic and carbonate platform deposits deformed in sequential fold sets: first in tight to isoclinal, reclined, west-verging folds of thin beds with axial-plane cleavage; then in major and minor, close, west-verging folds of beds and first cleavage, with formation of a second axial plane cleavage. First- and second-phase folds are transected by the Fencemaker thrust, which could be contemporaneous or later than shelf folding.

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