The Perfect Practice Test For Geology Exams

59 Questions | By Hanaxxx | Updated: Mar 20, 2022 | Attempts: 254

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The Perfect Practice Test For Geology Exams - Quiz

When people tell you that this quiz is the hardest one, they have come across when it comes to Geology you may doubt it and aim to try it. Do you think that you have what it takes to tackle it? Why don’t you take it up and share your results with us so that we can compare how good you are by show of your certificate. All the best, and you have been warned!

Questions and Answers

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
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
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
4.

________ magma cools and consolidates without growth of mineral grains
- A.
  
  Aphanitic
- B.
  
  Porphyritic
- C.
  
  Phaneritic
- D.
  
  Glassy
5.

________ mineral grains are of roughly equal size and coarse enough to be seen without a microscope or magnifying glass
- A.
  
  Aphanitic
- B.
  
  Porphyritic
- C.
  
  Phaneritic
- D.
  
  Glassy
6.

________ rock has two or more, distinctly different-sized populations of mineral grains
- A.
  
  Aphanitic
- B.
  
  Porphyritic
- C.
  
  Phaneritic
- D.
  
  Glassy
7.

________ a magnifying glass or microscope is needed to see individual mineral grains
- A.
  
  Aphanitic
- B.
  
  Porphyritic
- C.
  
  Phaneritic
- D.
  
  Glassy
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
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
10.

Which of the following igneous rocks exhibit aphanitic texture?
- A.
  
  granite; gabbro
- B.
  
  Andesite; rhyolite
- C.
  
  Andesite; diorite
- D.
  
  Rhyolite; gabbro
11.

In a porphyritic volcanic rock, which mineral grains are the last to crystallize?
- A.
  
  Phenocrysts
- B.
  
  Vesicles
- C.
  
  Pegmatites
- D.
  
  Matrix or groundmass
12.

Visible quartz and potassium feldspar grains are the main constituents in a ________.
- A.
  
  Granite
- B.
  
  Gabbro
- C.
  
  Basalt
- D.
  
  Rhyolite
13.

Which of the following igneous rocks has a pyroclastic texture?
- A.
  
  Rhyolitic tuff
- B.
  
  Porphyritic basalt
- C.
  
  Intrusive granite
- D.
  
  Andesitic lava
14.

________ is a volcanic rock that is extremely vesicular and glassy.
- A.
  
  Obsidian
- B.
  
  Pegmatite
- C.
  
  Tuff
- D.
  
  Pumice
15.

________ is composed mainly of ferromagnesian minerals.
- A.
  
  Peridotite
- B.
  
  Rhyolite
- C.
  
  Andesite
- D.
  
  Granite
16.

Which of the following minerals crystallize early in Bowen's reaction series?
- A.
  
  Biotite
- B.
  
  Quartz
- C.
  
  Olivine
- D.
  
  Muscovite
17.

________ is the dominant feldspar in basalt.
- A.
  
  Plagioclase
- B.
  
  Microcline
- C.
  
  Orthoclase
- D.
  
  Pyroxene
18.

Which of the following are used for studying rocks with a polarizing microscope?
- A.
  
  Polished cubes
- B.
  
  Broken chips
- C.
  
  Thin sections
- D.
  
  Grain karats
19.

________ is characterized by very coarse mineral grains?
- A.
  
  Obsidian
- B.
  
  Pumice
- C.
  
  Pegmatite
- D.
  
  Granite
20.

In which of the following igneous rocks and environments would you expect to find unusually high concentrations of rare elements such as lithium, beryllium, and boron?
- A.
  
  Basalt dike; fills a vertical fracture at shallow depth
- B.
  
  Pumice lump; crystallized at depth in a mass of intrusive granite
- C.
  
  Peridotite; crystallized at depth in the upper mantle
- D.
  
  Pegmatite; crystallized from a water-rich, highly differentiated, residual magma
21.

A (an) ________ texture represents a single, long period of cooling and crystallization.
- A.
  
  Glassy
- B.
  
  Pyroclastic
- C.
  
  Aphanitic
- D.
  
  Phaneritic
22.

________ has the same mineral composition as andesite?
- A.
  
  Basalt
- B.
  
  Granite
- C.
  
  Gabbro
- D.
  
  Diorite
23.

What do pumice and obsidian have in common?
- A.
  
  Basaltic composition
- B.
  
  Glassy texture
- C.
  
  Ultramafic composition
- D.
  
  Phaneritic texture
24.

Which of the following best describes an aphanitic texture?
- A.
  
  The rock is crystalline; mineral grains are too small to be visible without a magnifying lens or microscope
- B.
  
  The mineral grains have glassy textures.
- C.
  
  The rock consists of broken, volcanic-rock and mineral fragments.
- D.
  
  The rock is crystalline; mineral grains are of distinctly different sizes.
25.

A ________ texture would be most unlikely to occur in an extrusive igneous rock.
- A.
  
  Pyroclastic
- B.
  
  Glassy
- C.
  
  Aphanitic
- D.
  
  Phaneritic