Early Mesozoic Tectonics of the Western Great Basi n, Nevada: Battle Mountain to Yerington District, Nevada, July 1–7, 1989, Field Trip Guidebook T122

Published by the American Geophysical Union as part of the Field Trip Guidebooks Series, Volume 122.

This excursion will present an overview of the stratigraphy, structure, and tectonic evolution of the margin of early Mesozoic North America in the Great Basin and of terranes tectonically accreted above and against this margin. Exposures to be visited will show the following features: 1) the Golconda allochthon, a tract of oceanic Paleozoic rocks that was thrust some 100 km across the edge of Triassic North America; 2) shelfal and platformal lower Mesozoic strata that unconformably cover the Golconda allochthon; 3) basinal lower Mesozoic strata that accumulated seaward of the inherited continental edge; 4) Mesozoic and Paleozoic arc volcanics; and 5) Jurassic and Cretaceous foreland structures developed in all the preceding rocks after accretion of terranes had left the early Mesozoic sialic margin well inboard of the active convergent margin.

This guide begins with introductions to the neotectonic and Phanerozoic paleotectonic evolutions of the Great Basin. Thereafter, its contents are organized in sequence with field trip stops which are as follows [route map in Figs. 5 and 6]:
Day 1. Battle Mt. Golconda allochthon.
Day 2. Tobin, Stillwater, and southern Humboldt Ranges. Stratigraphy of platform to basin transition of Triassic cover, Jurassic foreland thrusting; 1915 Pleasant Valley earthquake scarp.
Day 3. Sand Springs and Paradise Ranges. Terranes of volcanogenic Triassic and Paleozoic rocks structurally outboard of parautochthonous lower Mesozoic basinal and shelf edge rocks.
Days 4 and 5. Mina and Candelaria. North-south traverse across structurally condensed Early Triassic collision zone of exotic Paleozoic arc, Golconda allochthon plus serpentinite melange, Golconda foreland basin strata on Early Triassic North America; these units were covered by Middle and Upper Triassic strata and imbricated with the cover in late Mesozoic foreland thrusting.
Day 6. Yerington. Stratigraphy and structure of possibly oldest continental magmatic arc rocks in western Great Basin.