thumbnail

Stratigraphy of the unsaturated zone at the radioactive waste management complex, Idaho National Engineering Laboratory, Idaho

Water-Resources Investigations Report 89-4065

By:
,

Links

Abstract

A complex sequence of layered basalt flows, cinders, and sediment underlies the Radioactive Waste Management Complex at the Idaho National Engineering Laboratory in southeastern Idaho. Wells drilled to 700 ft penetrate a sequence of 10 basalt-flow groups and 7 major sedimentary interbeds that range in age from about 100,000 to 600,000 years old. The 10 flow groups consist of 22 separate lava flows and flow-units. Each flow group is made up of from one to five petrographically similar flows that erupted from common source areas during periods of less than 200 years. Sedimentary interbeds consist of fluvial, lacustrine, and wind-blown deposits of clay, silt, sand, and gravel that accumulated during periods of volcanic inactivity ranging from thousands to hundreds of thousands of years. Flows and sediment are unsaturated to a depth of about 600 ft. Flows and sediment below a depth of 600 ft are saturated and make up the uppermost part of the Snake River Plain aquifer. The areal extent of flow groups and interbeds was determined from well cuttings, cores, geophysical logs, potassium-argon ages, and geomagnetic properties. Stratigraphical control was provided by four sequential basalt flows near the base of the unsaturated zone that have reversed geomagnetic polarity and high emission of natural gamma radiation compared to other flows. Natural gamma logs were used as a primary correlation tool. Natural-gamma emissions, which are generally uniform in related, petrographically similar flows, increase or decrease between petrographically dissimilar flows of different age and source. (USGS)

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Stratigraphy of the unsaturated zone at the radioactive waste management complex, Idaho National Engineering Laboratory, Idaho
Series title:
Water-Resources Investigations Report
Series number:
89-4065
Edition:
-
Year Published:
1989
Language:
ENGLISH
Publisher:
U.S. Geological Survey ; Copies of this report can be purchased from Books and Open-File Reports Section,
Description:
v, 54 p. :ill ;28 cm.