Accession Number:

AD0829033

Title:

ENGINEERING GEOLOGY OF ROCKS IN CORE HOLE, EEL POINT, SAN CLEMENTE ISLAND, CALIFORNIA,

Descriptive Note:

Corporate Author:

LAMAR-MERIFIELD SANTA MONICA CA

Personal Author(s):

• Lamar, D. L.
• Merifield, P. M.
• Stout, M. L.

Report Date:

1968-02-01

Pagination or Media Count:

17.0

Abstract:

A 1,200-foot core hole drilled near Eel Point on the west coast of San Clemente Island, California, penetrated a homogeneous series of andesite flows varying in thickness from 11 to 169 feet. Petrographic examination revealed that textural variations within flows as a result of different cooling rates are more distinct than differences in composition between individual flows. Potassium-argon dates indicate that these flows were extruded in less than one-half million years during Miocene time. The flows are inferred to dip seaward at between 10 and 30 degrees. The rock will provide sound material for excavation. Problems of water leakage can be expected at faults and zones of decomposed rock. Author

Descriptors:

• (*ENGINEERING GEOLOGY
• CALIFORNIA)
• DRILLING
• ROCK
• GEOLOGIC AGE DETERMINATION
• IGNEOUS ROCK
• FAULTS(GEOLOGY)
• POTASSIUM
• ARGON
• PETROGRAPHY
• THICKNESS
• COOLING
• VOLCANOES
• STRUCTURAL GEOLOGY

Subject Categories:

• Geology, Geochemistry and Mineralogy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE