Award Date

5-1981

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Geoscience

Number of Pages

66

Abstract

A landslide breccia of plutonic and metamorphic rocks located 20 km east of Las Vegas, Nevada is interstratified with the late Tertiary Thumb Formation. Rock types of similar mineral composition to the landslide masses in the Rainbow Gardens are found 60 km to the east in the Gold Butte (Nevada) area. The landslide masses were displaced into their present position by lateral strike-slip motion along either the left-lateral Lake Mead fault system or the right-lateral Las Vegas shear zone. In the Rainbow Gardens landslide masses, five plutonic rock types, including Rapakivi granite, match rocks from the Gold Butte area, both megasopically and petrographically. Rapakivi granite also crops out in the El Dorado and Newberry Mountains but other rock types in the range do not correlate with the Rainbow Gardens plutonic and metamorphic rocks. Distribution of the rock types in the landslide masses is non-random. This suggest that at the time of sliding the source terrain was nearby, and that the landslide masses moved as distinct toes, each characterized by a distinctive lithologic type. The Rainbow Gardens landslide masses were emplaced at the same as the red Thumb sandstone. This is evidenced by incorporated masses of gneissic clasts in a matrix of Thumb sandstone at the lower contact of the landslide blocks, and the presence of intrusive Thumb sandstone dikes.

Keywords

Landforms; Landslides; Nevada – Rainbow Gardens (Clark County); Sedimentary rocks; United States – Lake Mead Region

Disciplines

Geology | Geomorphology | Sedimentology

Language

English


Share

COinS