Metamorphosed volcanogenic rocks of the Permian and Triassic Seven Devils Group are exposed in the northern part of the Heavens Gate 7.5 minute quadrangle, western Idaho. These rocks originated in a volcanic arc at a destructive plate margin. In the north, rocks that probably belong to the Lower Permian Hunsaker...
The Greenhorn Mountains contain a tectonic ally disrupted
ophiolite and both arc-derived and pelagic sediments. Age of major
sedimentary units within and bordering the thesis area is Early
Permian, based upon dates of conodonts and fusulinids from contemporaneous
but allocthanous limestones. Sediments near the south
boundary of the thesis area...
The thesis area is located in the Blue Mountains of northeast Oregon. Pre-Tertiary and Cenozoic rocks, divided on the basis of age and tectonic history, are exposed along the eroded crest of the Blue Mountain anticline. Permian (?) metasedimentary rocks probably correlate with the Elkhorn Ridge Argillite, and consist mainly...
Nine small Mesozoic plutons in TJmatilla County, northeast Oregon, crop out within an area of 58 sq km in the Blue Mountains. The plutons are divided into an earlier series of probable Permian-Triassic age and a later intrusive series of probable Late Jurassic to Middle Cretaceous age. The earlier rocks...
Eleven small Mesozoic plutons crop out within a 76-squaremile
area of the southern Seven Devils Mountains in west-central
Idaho. The plutons are divided into a mafic suite, an older granitic
suite, and a younger granitic suite on the basis of age, lithology, and
degree of metamorphism.
The six plutons of...
The mapped area lies between the Wallowa Mountains
of northeastern Oregon and the Seven Devils Mountains of
western Idaho. Part of the Snake River canyon is included.
A composite stratigraphic section includes at least
30,000 feet of strata. Pre- Tertiary and Tertiary strata
are separated by a profound unconformity. Pre...
Within 40 square miles of the southeastern Wallowa Mountains, Oregon, eugeosynclinal Permian and Triassic formations comprising a section about 25,000 feet thick have been exposed by uplift and erosion of overlying Miocene Columbia River basalt. Deposition appears to have been continuous from Permian into Upper Triassic, but an apparent angular...