How are primary foliations recognized in deformed and metamorphosed sedimentary rocks?
What will be an ideal response?
Answer: Primary sedimentary structures are not always easy to distinguish from secondary structures. One would, mentally or quantitatively (if possible), account for the strain in the rock to restore the structure to its predeformational state. Cross-stratification is a characteristic feature, and the angular relations of cross-stratification will change during deformation, depending on the type and quantity of strain. Be aware of pseudo cross-stratification created by sheared fold hinges (see Figure Q12.2). Look for remnants of fold hinges along the structure (see red circle in Figure Q12.2).
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a. true b. false
What is the role that depth can play on cooling and crystallization of igneous rocks?
What will be an ideal response?
What was the first rail hub of the United States?
A) Atlanta, Georgia B) Boston, Massachusetts C) Chicago, Illinois D) Denver, Colorado E) Erie, Pennsylvania
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A. denser B. less dense C. less electrically charged D. less energetic E. more electrically charged