Page 167 - Laboratory Manual in Physical Geology

A CTIVIT Y 5.6 Rock Analysis, Classification, and Origin

Name: ______________________________________ Course/Section: ______________________ Date: ___________

A. Analyze and classify each igneous rock below, then infer the origin of each rock based on its texture. Refer to FIGURE 5.4 and

5.5 as needed. The rocks are shown ×1 (actual size).

Mafic color index (MCI, Mafic color index (MCI, Mafic color index (MCI, Mafic color index (MCI,
percentage of mafic mineral percentage of mafic mineral percentage of mafic mineral percentage of mafic mineral
crystals): crystals): crystals): crystals):

Would you describe the Would you describe the Would you describe the Would you describe the
rock as mafic, intermediate, rock as mafic, intermediate, rock as mafic, intermediate, rock as mafic, intermediate,
or felsic? or felsic? or felsic? or felsic?

Texture(s) present: Texture(s) present: Texture(s) present: Name and percent
abundance of mineral
crystals:

Texture present:

The name of this rock is: The name of this rock is: The name of this rock is: The name of this rock is:

Based on its texture, how Based on its texture, how Based on its texture, how Based on its texture, how
did this rock form? did this rock form? did this rock form? did this rock form?

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