GEOL 201: GEOLOGY BASICS EXAM
QUESTIONS WITH VERIFIED ANSWERS
What are rocks composed of?
Minerals, rock fragments, and fossils
Name three characteristics of minerals.
1. Inorganic (not living matter)
2. Naturally occurring
3. Crystalline solids
What influences the physical properties of minerals?
Their unique chemical composition.
What are the two most common elements in rocks and minerals?
Oxygen and Silicon
Silicate minerals
Composed of oxygen and silicon.
The Silica Tetrahedron
The basic building block of most minerals, such as feldspar, muscovite mica, olivine, quartz,
pyroxene
What is the largest reservoir of carbon on the planet?
Carbonate minerals
What can carbonate minerals do when reacting with other substances, like acid?
They can either trap carbon as a solid rock or release it back out (in reaction to acid).
Igneous rocks
Crystallizes from cooling molten material.
How do intrusive igneous rocks form?
Magma cools slowly while trapped beneath the surface.
How do extrusive igneous rocks form?
Magma/lava cools quickly above the surface, usually through volcanoes.
Physical qualities of intrusive igneous rocks
, Coarse-grained (because it cools slowly, allowing bigger crystals to form), interlocking texture.
Resistant to erosion.
Geometry of igneous intrusive rocks
Magma rises from below and "intrudes" on older surrounding rock. The flat exposed face is
called a dyke.
Physical qualities of extrusive igneous rocks
Fine-grained, interlocking texture.
Sedimentary rocks
Rocks formed from other rocks that have been deposited elsewhere through weather, erosion, or
tides.
What are the particles that form sedimentary rocks?
Sediment and detritus. EX: dirt and sand
Clastic/detrital sedimentary rocks
Various rock components (minerals, rock fragments, or fossils) are cemented together by quartz
or calcite.
Chemical sedimentary rocks
Formed by the chemical precipitation of minerals from water, usually evaporite minerals like
gypsum and halite (table salt).
Carbonate minerals/rocks
Forms in ocean environments with the calcite shells of sea animals. It becomes limestone when
calcite precipitates.
Geometry and features of chemical sedimentary rocks
forms in layers or beds
Metamorphic rocks
Rocks that have recrystallized through extreme heat or pressure.
Foliated texture
Metamorphic rocks have a foliated texture, as minerals are compressed under directed pressure.
Chemical Composition of the Crust
46% Oxygen, 28% Silicon (mostly silicates)
Chemical Composition of the whole Earth
QUESTIONS WITH VERIFIED ANSWERS
What are rocks composed of?
Minerals, rock fragments, and fossils
Name three characteristics of minerals.
1. Inorganic (not living matter)
2. Naturally occurring
3. Crystalline solids
What influences the physical properties of minerals?
Their unique chemical composition.
What are the two most common elements in rocks and minerals?
Oxygen and Silicon
Silicate minerals
Composed of oxygen and silicon.
The Silica Tetrahedron
The basic building block of most minerals, such as feldspar, muscovite mica, olivine, quartz,
pyroxene
What is the largest reservoir of carbon on the planet?
Carbonate minerals
What can carbonate minerals do when reacting with other substances, like acid?
They can either trap carbon as a solid rock or release it back out (in reaction to acid).
Igneous rocks
Crystallizes from cooling molten material.
How do intrusive igneous rocks form?
Magma cools slowly while trapped beneath the surface.
How do extrusive igneous rocks form?
Magma/lava cools quickly above the surface, usually through volcanoes.
Physical qualities of intrusive igneous rocks
, Coarse-grained (because it cools slowly, allowing bigger crystals to form), interlocking texture.
Resistant to erosion.
Geometry of igneous intrusive rocks
Magma rises from below and "intrudes" on older surrounding rock. The flat exposed face is
called a dyke.
Physical qualities of extrusive igneous rocks
Fine-grained, interlocking texture.
Sedimentary rocks
Rocks formed from other rocks that have been deposited elsewhere through weather, erosion, or
tides.
What are the particles that form sedimentary rocks?
Sediment and detritus. EX: dirt and sand
Clastic/detrital sedimentary rocks
Various rock components (minerals, rock fragments, or fossils) are cemented together by quartz
or calcite.
Chemical sedimentary rocks
Formed by the chemical precipitation of minerals from water, usually evaporite minerals like
gypsum and halite (table salt).
Carbonate minerals/rocks
Forms in ocean environments with the calcite shells of sea animals. It becomes limestone when
calcite precipitates.
Geometry and features of chemical sedimentary rocks
forms in layers or beds
Metamorphic rocks
Rocks that have recrystallized through extreme heat or pressure.
Foliated texture
Metamorphic rocks have a foliated texture, as minerals are compressed under directed pressure.
Chemical Composition of the Crust
46% Oxygen, 28% Silicon (mostly silicates)
Chemical Composition of the whole Earth
