Geology 1 Questions for Chapter 4 1) Lava flows are typically finer ...
Geology 1 Questions for Chapter 4 1) Lava flows are typically finer ...
Geology 1 Questions for Chapter 4 1) Lava flows are typically finer ...
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13) Which of the following igneous rocks exhibit aphanitic texture?<br />
A) granite; gabbro<br />
B) andesite; rhyolite<br />
C) andesite; diorite<br />
D) rhyolite; gabbro<br />
14) In a porphyritic volcanic rock, which mineral grains <strong>are</strong> the last to crystallize?<br />
A) phenocrysts<br />
B) vesicles<br />
C) pegmatites<br />
D) matrix or groundmass<br />
The correct answer is 'D'.<br />
Phenocrysts <strong>are</strong> the first<br />
minerals to crystallize.<br />
15) Visible quartz and potassium feldspar grains <strong>are</strong> the main constituents in a ________.<br />
A) granite<br />
B) gabbro<br />
C) basalt<br />
D) rhyolite<br />
16) Which of the following igneous rocks has a pyroclastic texture?<br />
A) rhyolitic tuff<br />
B) porphyritic basalt<br />
C) intrusive granite<br />
D) andesitic lava<br />
17) ________ is a volcanic rock that is extremely vesicular and glassy.<br />
A) Obsidian<br />
B) Pegmatite<br />
C) Tuff<br />
D) Pumice<br />
18) ________ is composed mainly of ferromagnesian minerals.<br />
A) Peridotite<br />
B) Rhyolite<br />
C) Andesite<br />
D) Granite<br />
19) Which of the following minerals crystallize early in Bowen's reaction series?<br />
A) biotite<br />
B) quartz<br />
C) olivine<br />
D) muscovite<br />
20) ________ is the dominant feldspar in basalt.<br />
A) Plagioclase<br />
B) Microcline<br />
C) Orthoclase<br />
D) Pyroxene<br />
21) Which of the following <strong>are</strong> used <strong>for</strong> studying rocks with a polarizing microscope?<br />
A) polished cubes<br />
B) broken chips<br />
C) thin sections<br />
D) grain karats