By: D. M. Miller and A. P. Lush
The Pilot Peak quadrangle straddles the Utah-Nevada border in northwestern Utah and northeastern Nevada, and includes much of the highest part of the central Pilot Range. Flanking the range are piedmonts; on the west side is part of a broad, west-sloping piedmont, whereas that on the east side is steeper and narrower. The north-trending fault block forming the Pilot Range contains structures and rock units typical of the northern Basin and Range Province. Bedrock in this fault block constitutes two lithotectonic domains that are separated by the Pilot Peak detachment fault at the south end of the quadrangle. Most rock units in the quadrangle lie below the fault. These rocks are mostly Late Proterozoic and Cambrian siliciclastic strata that typically have well-developed tectonite fabrics caused by Mesozoic ductile deformation and metamorphism. Generally unmetamorphosed Ordovician to Permian carbonate strata lie above the fault. Flanking the Pilot Range are young sedimentary basins formed during tectonic extension. The presumably middle Cenozoic deposits of these basins are concealed by Pliocene(?) to Quaternary alluvial deposits and Pleistocene lacustrine deposits of Lake Bonneville.
Pages: 25 p.
Plates: 2 pl.
Location: Box Elder County
Media Type: Paper Map