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-Field classification of igneous rocks (modified after R.B. Travis [1955]).

-Field classification of igneous rocks (modified after R.B. Travis [1955]).

Source publication
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U S Bureau of Reclamation Filed Manual for engineering geologic logging.

Contexts in source publication

Context 1
... figures are condensed and modified slightly from Travis' classifications, but the more detailed original classifications of Travis are acceptable. Figure 4-5 or appropriate American Geological Institute (AGI) data sheets are suggested for use when estimating composition percentages in classification. ...
Context 2
... zones may have minor or major lateral variations in the percentages of components within short distances at an exposure. The shear zone illustrated in figure 5-4 consists of 60 percent clay gouge and 40 percent rock fragments. Because the various components are not arranged in layers, the shear is of the uniform type. ...
Context 3
... of Logs Based on Laboratory Classification.-When logs are prepared using laboratory classifications (based on laboratory tests), the information must be presented on the log as shown in figure 11-4. The difference between a laboratory and a visual classification is depicted in figure 11-6. ...
Context 4
... of Custody.-Once all samples for a specific sampling task have been collected, the sampler(s) will complete the chain of custody record ( figure 12-4). Specific procedures for completing this form should be included in the work plan documents specific to the project. ...