CSS - PMS - CCE - PCS - Geography
Rocks and Minerals
Clastic sedimentary rocks are classified mainly by:
A. Fossil age
B. Grain size
C. Magnetic polarity
D. Latitude
Correct Answer: B
Clastic rocks such as conglomerate, sandstone and shale are distinguished largely by particle size.
CSS - PMS - CCE - PCS - Geography
Rocks and Minerals
Sedimentary rocks commonly form through:
A. Melting only
B. Deposition, compaction and cementation
C. Sublimation only
D. Core crystallization
Correct Answer: B
Lithification converts deposited sediment into sedimentary rock.
CSS - PMS - CCE - PCS - Geography
Rocks and Minerals
Pumice commonly forms from:
A. Gas-rich felsic lava
B. Deep burial of shale
C. Cemented sand
D. Pure calcite precipitation
Correct Answer: A
Escaping gas creates abundant vesicles in rapidly cooled lava.
CSS - PMS - CCE - PCS - Geography
Rocks and Minerals
Obsidian is characterized by:
A. Glassy texture
B. Large fossils
C. Strong foliation
D. Rounded pebbles
Correct Answer: A
Very rapid cooling can produce volcanic glass.
CSS - PMS - CCE - PCS - Geography
Rocks and Minerals
Basalt is typically:
A. Felsic intrusive
B. Mafic extrusive
C. Chemical sedimentary
D. Metamorphic
Correct Answer: B
Basalt is a dark, mafic volcanic rock common in oceanic crust.
CSS - PMS - CCE - PCS - Geography
Rocks and Minerals
Granite is typically:
A. Intrusive felsic igneous rock
B. Extrusive mafic rock
C. Clastic sedimentary rock
D. Foliated metamorphic rock
Correct Answer: A
Granite is coarse-grained, silica-rich and intrusive.
CSS - PMS - CCE - PCS - Geography
Rocks and Minerals
Extrusive igneous rocks typically have:
A. Coarse crystals
B. Fine-grained texture
C. Foliation
D. Abundant fossils
Correct Answer: B
Rapid surface cooling limits crystal growth.
CSS - PMS - CCE - PCS - Geography
Rocks and Minerals
Intrusive igneous rocks cool:
A. Rapidly at the surface
B. Slowly below the surface
C. Only under oceans
D. Without crystallizing
Correct Answer: B
Slow subsurface cooling generally produces coarse crystals.
CSS - PMS - CCE - PCS - Geography
Rocks and Minerals
Igneous rocks form by:
A. Compaction of fossils
B. Cooling and solidification of magma or lava
C. Weathering only
D. Evaporation of rivers
Correct Answer: B
Igneous rocks crystallize from molten material.
CSS - PMS - CCE - PCS - Geography
Rocks and Minerals
The three major rock groups are:
A. Igneous, sedimentary and metamorphic
B. Granite, basalt and marble
C. Metallic, non-metallic and organic
D. Crustal, mantle and core
Correct Answer: A
Rocks are genetically classified as igneous, sedimentary or metamorphic.