Boundary Peak
       7 ½’ quadrangle: Boundary Peak, NV-CA
       Esmeralda County
       Inyo National Forest
       White Mountains

Igneous Intrusive
13,143 ft (4006 m)

Boundary Mountain from the northwest. (1979)

Bedrock: Boundary Peak Adamellite

Cretaceous 72 Ma

White, equigranular, medium-grained, homogeneous biotite adamellite (leucocratic quartz monzonite), with minor garnet in Trail Canyon Saddle. Forms blocky outcrops except below 10,000 feet on the east side, where spheroidal weathering and grüs are common. Near the summit the biotite adamellite forms a flat dome plunging south and west under the Pellisier Flats Adamellite. The latter is a gray, Jurassic, hornblende-biotite adamellite, which also caps nearby Montgomery Peak in California, slightly higher at 13,447 feet.

These rocks lie within a horst east of the Benton Valley graben. Within the horst along the western side, dextral transpressional shear along the White Mountain Shear Zone marks the contact between the Jurassic adamellite and Cambrian marble. However, the Boundary Peak adamellite is not sheared and is thus apparently younger than the shear zone. On the east side of Boundary Peak, Trail Canyon cuts into Ordovician slate and Tertiary rhyolite tuff.

Surficial Geology: In Pleistocene time, small glaciers formed at the heads of valleys on the east side of the White Mountains south of Boundary Peak, creating shallow cirques and filling valleys with glacial deposits.

Soil Series: Published soil survey of Esmeralda County does not include the portion in Inyo National Forest.

Additional Photos:

Boundary Peak from the northeast.
Trail Canyon Saddle to the right. (1979)

The summit from the north, as seen from the cone-shaped peak
in the middle of the previous photo. (1979)

Selected References:

  • Bateman, P.C., 1992, Pre-Tertiary bedrock geologic map of the Mariposa 1 degree by 2 degree quadrangle, Sierra Nevada, California and Nevada: USGS Open File Report Map OF-87-670, 1:200,000.
  • Sullivan, Walter A. and Richard D. Law, 2003, Geometry, kinematics and age of the northern half of the White Mountains Shear Zone: extending the range and duration of the late Cretaceous dextral transpression along the western margin of North America: Geological Society of America Abstracts, v.35, no.6, p.114.

Other suggested sources of information:

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