Chapter 4 - Multiple-Choice Questions 1) Lava flows are...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Multiple-Choice Questions 1) Lava flows are typically finer grained than intrusive igneous rocks. Why? A) Intrusive magma is cooler because it is well insulated by the surrounding rock. B) Intrusive magma flows onto the Earth's surface and cools very slowly, allowing many small mineral grains to grow. C) The extrusive magma cools quickly so the mineral grains do not have time to grow. D) The extrusive magma, because it is deep below the surface, cools very slowly producing very small mineral grains. Answer: C Diff: 1 2) Which magma is most likely to quench (congeal) to a natural glass? A) highly viscous; cools quickly B) highly viscous; cools slowly C) highly fluid; cools slowly D) highly fluid; cools quickly Answer: A Diff: 1 3) The sizes, shapes, and arrangements of mineral grains in an igneous rock is known as __________. A) silica content B) texture C) mineral content D) Bowen's reaction series Answer: B Diff: 1 Match the description with the appropriate texture. A. aphanitic B. porphyritic C. phaneritic D. glassy 4) _____ magma cools and consolidates without growth of mineral grains Answer: D Diff: 1 6) _____ mineral grains are of roughly equal size and coarse enough to be seen without a microscope or magnifying glass Answer: C Diff: 1 7) _____ rock has two or more, distinctly different-sized populations of mineral grains Answer: B Diff: 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
8) _____ a magnifying glass or microscope is needed to see individual mineral grains Answer: A Diff: 1 8) A __________ is an open cavity in a volcanic rock that was filled by a gas bubble when the lava was still mainly liquid? A) porphyrocryst B) vesicle C) phenocryst D) xenocryst Answer: B Diff: 1 9) Consider the Bowen's reaction series. Which mineral would you expect to see as a phenocryst in a porphyritic basalt? A) olivine B) quartz C) orthoclase D) sodium-rich plagioclase Answer: A Diff: 1 Match the following rocks to their equivalent aphanitic or phaneritic igneous rocks. A. andesite B. gabbro C. rhyolite 10) _____ granite Answer: C Diff: 1 11) _____ basalt Answer: B Diff: 1 12) _____ diorite Answer: A Diff: 1 13) Which of the following igneous rocks exhibit aphanitic texture? A) granite; gabbro B) andesite; rhyolite C) andesite; diorite D) rhyolite; gabbro Answer: B Diff: 1
Background image of page 2
14) In a porphyritic volcanic rock, which mineral grains are the last to crystallize? A) phenocrysts B) vesicles C) pegmatites D) matrix or groundmass Answer: D Diff: 1 15) Visible quartz and potassium feldspar grains are the main constituents in a ____________. A) granite B) gabbro C) basalt D) rhyolite Answer: A Diff: 1 16) Which of the following igneous rocks has a pyroclastic texture? A) rhyolitic tuff B) porphyritic basalt C) intrusive granite D) andesitic lava Answer: A Diff: 1 17) __________ is a volcanic rock that is extremely vesicular and glassy. A) Obsidian
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 11

Chapter 4 - Multiple-Choice Questions 1) Lava flows are...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online