Page 201 - Laboratory Manual in Physical Geology

A CTIVIT Y 6.6 Hand Sample Analysis and Interpretation

Name: ______________________________________ Course/Section: ______________________ Date: ___________

How Did the Rock Form? (See Figure 6.10) Preexisting rock exposed on land (probably granite) was Grains were not rounded or sorted much, so not transported very far from their source. mixed with some green silt, deposited, and (compaction?) into rock.

weathered. they were Grains were hardened

SEDIMENTARY ROCKS WORKSHEET

Rock Name (Figure 6.9) Breccia (Arkose breccia)

Textural and Other Distinctive Properties (Figures 6.3 and 6.9) • Mostly (~95%) angular to subangular gravel-sized grains • Poorly sorted (The gravel is mixed with some sand and green silt)

Composition (Figures 6.2 and 6.9) Detrital (Siliciclastic): • Mostly orange feldspar grains (~85%) • Some quartz (~10%) • Green silty matrix (~5%)

Sample Number or Letter Fig. 6.11

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