Location of rock exposure(s) on a topographic map, particularly with respect to

the site being investigated, including strike and dip measurements for

sedimentary rock strata, and orientation, bearing and plunge measurements for

predominant metamorphic/igneous linear features (large and small scale).

Photograph(s) of exposure(s).

Measured section, with name(s) of stratigraphic units present. A measured

section includes a bed by bed description of the exposure using appropriate

lithologic terminology. A scale drawing or photograph of the section,

including sample locations, should be part of the outcrop description.

Structural features such as folds, faults, joints, fractures, cleavage, schistosity,

and lineation. Other features that can control the hydraulic properties of the

units such as solution cavities also should be noted. It is important to

determine the orientation of these features, as they may exert significant

influence on the local or regional movement of ground water. When

sedimentary strata are nearly horizontal and structurally uncomplicated, the

orientation of any joints not parallel to bedding should be determined, as

movement of ground water along joints and bedding planes can be a significant

part of the ground water flow regime.

Where fractures, faults, or subsurface conduits exist, maps of fracture traces, fault

traces, and subsurface conduits should be included as part of, or in addition to, the geologic

map prepared for the site. Mapping of subsurface conduits is successfully accomplished by

performing tracer studies. Fracture trace mapping is performed by analyzing aerial

photographs, and is often supplemented with information from field reconnaissance, tracer

tests, and/or geophysical investigations.

Soil maps are typically available from the U.S. Department of Agriculture's Soil

Conservation Service. A soil map should be prepared for facilities that do not have one

available, or for facilities where existing soil maps are incomplete or out of date (e.g., soils

have been disturbed). A soil survey will involve mapping soils with respect to their unit and

type, based primarily on grain size distribution.

4.2.4

Cone Penetrometer Survey

Cone penetrometer testing (CPT) consists of advancing an electric, telescoping

penetrometer tip into a subsurface formation to determine the end bearing and side friction

components of penetration resistance (ASTM D3441 86). Application of the CPT method is

limited by the availability of equipment and by the relatively few contractors that offer

conventional or specialized CPT services. In all cases, lithologic data obtained from CPT

November 1992

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