Geology of the southwestern Pasco Basin

Technical Report · Fri Sep 01 04:00:00 EDT 1978

OSTI ID:5817982

The objective of this study was to define those aspects of the stratigraphic, structural, and tectonic setting which are important to the integrity of a deep-mined waste-isolation cavern in the Columbia River basalts. Three principal structural features received the focus of the field effort in the 1,485-square-kilometer area. These are the northern end of the Horse Heaven uplift, the linear ridges of the Badger Mountain-Red Mountain trend, and the Rattlesnake uplift. The thickest sequence of basalt exposed in the study area is on the steep, northeastern slope of Rattlesnake Mountain; about 485 meters of stratigraphic section can be examined in the field area. Subsidence and weak deformation of the southwestern Pasco Basin area during Yakima time can be recognized in the disposition of flows and interbeds. In the southwestern Pasco Basin, most of the topographically expressed basalt bedrock mountains, ridges, hills, and knolls have developed since spreading of the Saddle Mountains flows. Deformation since Ice Harbor time (about 8 million years ago) has been by folding, faulting, and in some structures, by a combination of both. The doubly plunging anticlinal folds of Badger Mountain, Red Mountain, and easternmost Rattlesnake Hills have vertical structural amplitudes in the 80 to 200-meter range. The high-angle, possibly reverse Badger Mountain fault has offset up to 60 meters; offset is downward on the northeast. Rattlesnake Mountain is, in part, a tilted fault-block structure. The western end of the Rattlesnake uplift, Rattlesnake Hills, is principally a broad anticline with numerous minor folds and faults. Geomorphic relations suggest that the post-Ice Harbor structural movement in the study area is of one episode. 65 figures, 8 tables.

• Research Organization: Geoscience Research Consultants, Moscow, ID (USA)
• DOE Contract Number: EY-77-C-06-1030
• OSTI ID: 5817982
• Report Number(s): RHO-BWI-C-25
• Country of Publication: United States
• Language: English

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BASALT
CHEMICAL COMPOSITION
COLUMBIA RIVER BASIN
DATA
DATA FORMS
EXPERIMENTAL DATA
GEOLOGIC STRUCTURES
GEOLOGY
GEOMAGNETIC FIELD
GRAPHS
IGNEOUS ROCKS
INFORMATION
LITHOLOGY
MAGNETIC FIELDS
MANAGEMENT
MAPS
NORTH AMERICA
NUMERICAL DATA
PACIFIC NORTHWEST REGION
RADIOACTIVE WASTE DISPOSAL
ROCKS
STRATIGRAPHY
TABLES
TECTONICS
USA
WASHINGTON
WASTE DISPOSAL
WASTE MANAGEMENT