Lab Exercise - Igneous Rock Texture

Although Samples A and C in (first questions) appear different, they have very similar mineral compositions. Briefly explain what accounts for their different appearances.

"A" formed at great depth, "C" formed on the surface

Which sample(s) in Figure 2.9 (first question) exhibit(s) coarse-grained texture?

A, B, & E

Which sample(s) (A-H) exhibit(s) porphyritic texture?

B & G

Which of the sample(s) in Figure 2.9 (first question) exhibit(s) fine-grained texture?

C & F

Which of the sample(s) in Figure 2.9 (first question) exhibit(s) vesicular texture?

D

Which sample(s) in Figure 2.9 exhibit(s) glassy texture?

H

Complete the description of the environment in which coarse-grained igneous rocks form by choosing the appropriate terms: (1. at great depth or on the surface) (2. slowly or rapidly) (3. extrusive or intrusive). When molten rock solidifies (1) _______________ , it cools (2) ________________ and produces an (3)_________________ igneous rock. Which sentence below reads correctly?

When molten rock solidifies at great depth, it cools slowly and produces an intrusive igneous rock.

Complete the description of the environment in which fine-grained igneous rocks form by choosing the appropriate terms: (1. at great depth or on the surface) (2. slowly or rapidly) (3. extrusive or intrusive). When molten rock solidifies (1) _______________ , it cools (2) ________________ and produces an (3)_________________ igneous rock. Which sentence below reads correctly?

When molten rock solidifies on the surface, it cools rapidly and produces an extrusive igneous rock.