PHYSICAL GEOLOGY FINALS EXAMS ANSWERS AND
QUESTIONS SET A+
✔✔Volcanic/extrusive igneous rocks have _____ grain size, examples include -
✔✔Small grain size; basalt
✔✔Plutonic/intrusive igneous rock example: - ✔✔gabbro
✔✔Example of a Ultra-mafic, mafic, intermediate, and felsic rock - ✔✔UM: Peridotite
Mafic: basalt, gabbro
Intermediate: Diorite and andesite
Felsic (Granite and rhyolite)
✔✔Bowen's Reaction series - ✔✔Olivine, Pyroxene, Amphiboles, biotite from
discontinuously at declining temps. Calcium feldspar crystallizes on a gradient to
Sodium-rich feldspar. At the end sequence K-feldspar, muscovite/mica, and quartz
crystallize.
✔✔Causes of melting - ✔✔1. Decompression melting (melt temp increases with higher
pressure- while some cooling occurs with rising motion, because pressure also drops,
melting can occur)
2. The addition of volatiles (h2o, co2, oh- etc) lowers the melting point - common for
amphibole, mafic clays like biotite in ocean subduction zones
3. The addition of heat from hot rock plutons forming, bringing heat to the cooler, felsic
rocks above.
✔✔Dike, sill, lacolith - ✔✔Dike is a fissure the reaches the surface; sills are horizontal
igneous formation; lacoliths are intrusions injected between two layers of rock
✔✔Types of lava flow - ✔✔pyroclastic flow, ash flow, pahoehoe effusive flows
✔✔batholith - ✔✔network of plutons connecting through complex netowrk of dikes, sills
and lacoliths
, ✔✔Types of sedimentary rocks - ✔✔-Clastic sedimentary rocks
-chemical sedimentary rocks
✔✔Clastic sedimentary rocks - ✔✔A sedimentary rock composed of fragments of
preexisting rock.
✔✔TYPES of clastic rocks: gravels, sand, and mud - ✔✔Gravel --> conglomerate and
breccia; sand --> sandstone; mud --> shale, siltstone
✔✔Cementation - ✔✔The process in which minerals precipitate into pore spaces
between sediment grains and bind sediments together to form rock.
✔✔steps in the creation of sedimentary rocks - ✔✔1. Creation of rock fragments
through physical and chemical weathering and erosion (air, water, ice).
2. transport of particles
3. deposition of particles
4. lithification
✔✔lithification - ✔✔The process that converts sediments into solid rock by compaction
or cementation.
✔✔Types of chemical sedimentary rocks - ✔✔1. Evaporite rocks
2. Biochemical limestones
3. Organic sedimentary rocks
✔✔Evaporite rocks - ✔✔as water evaporates, the concentration of dissolved ions
increases, forcing some to precipitate out. Generally formed in layers from Calcite to
gypsum, to halite. An example of calcite is travertine.
✔✔Biochemical limestone - ✔✔CaCO3 skeletal (shell) remain dissolved and re-
precipitated.
✔✔organic sedimentary rocks - ✔✔Sedimentary rock that forms from the remains of
plants or animals (coal, organic shale)
✔✔Sedimentary rocks often form ___________ layers which are individually called
_____________, and as a unit are called a ______ - ✔✔horizontal; beds; strata
✔✔Glacial till environments form what type of sed. rocks/ sediments? - ✔✔diamictite,
poorly sorted sediments (glaciers pick up all sorts of things and drop them at random)
✔✔mountain streams form: - ✔✔conglomerates
✔✔sand dunes - ✔✔sand stones
QUESTIONS SET A+
✔✔Volcanic/extrusive igneous rocks have _____ grain size, examples include -
✔✔Small grain size; basalt
✔✔Plutonic/intrusive igneous rock example: - ✔✔gabbro
✔✔Example of a Ultra-mafic, mafic, intermediate, and felsic rock - ✔✔UM: Peridotite
Mafic: basalt, gabbro
Intermediate: Diorite and andesite
Felsic (Granite and rhyolite)
✔✔Bowen's Reaction series - ✔✔Olivine, Pyroxene, Amphiboles, biotite from
discontinuously at declining temps. Calcium feldspar crystallizes on a gradient to
Sodium-rich feldspar. At the end sequence K-feldspar, muscovite/mica, and quartz
crystallize.
✔✔Causes of melting - ✔✔1. Decompression melting (melt temp increases with higher
pressure- while some cooling occurs with rising motion, because pressure also drops,
melting can occur)
2. The addition of volatiles (h2o, co2, oh- etc) lowers the melting point - common for
amphibole, mafic clays like biotite in ocean subduction zones
3. The addition of heat from hot rock plutons forming, bringing heat to the cooler, felsic
rocks above.
✔✔Dike, sill, lacolith - ✔✔Dike is a fissure the reaches the surface; sills are horizontal
igneous formation; lacoliths are intrusions injected between two layers of rock
✔✔Types of lava flow - ✔✔pyroclastic flow, ash flow, pahoehoe effusive flows
✔✔batholith - ✔✔network of plutons connecting through complex netowrk of dikes, sills
and lacoliths
, ✔✔Types of sedimentary rocks - ✔✔-Clastic sedimentary rocks
-chemical sedimentary rocks
✔✔Clastic sedimentary rocks - ✔✔A sedimentary rock composed of fragments of
preexisting rock.
✔✔TYPES of clastic rocks: gravels, sand, and mud - ✔✔Gravel --> conglomerate and
breccia; sand --> sandstone; mud --> shale, siltstone
✔✔Cementation - ✔✔The process in which minerals precipitate into pore spaces
between sediment grains and bind sediments together to form rock.
✔✔steps in the creation of sedimentary rocks - ✔✔1. Creation of rock fragments
through physical and chemical weathering and erosion (air, water, ice).
2. transport of particles
3. deposition of particles
4. lithification
✔✔lithification - ✔✔The process that converts sediments into solid rock by compaction
or cementation.
✔✔Types of chemical sedimentary rocks - ✔✔1. Evaporite rocks
2. Biochemical limestones
3. Organic sedimentary rocks
✔✔Evaporite rocks - ✔✔as water evaporates, the concentration of dissolved ions
increases, forcing some to precipitate out. Generally formed in layers from Calcite to
gypsum, to halite. An example of calcite is travertine.
✔✔Biochemical limestone - ✔✔CaCO3 skeletal (shell) remain dissolved and re-
precipitated.
✔✔organic sedimentary rocks - ✔✔Sedimentary rock that forms from the remains of
plants or animals (coal, organic shale)
✔✔Sedimentary rocks often form ___________ layers which are individually called
_____________, and as a unit are called a ______ - ✔✔horizontal; beds; strata
✔✔Glacial till environments form what type of sed. rocks/ sediments? - ✔✔diamictite,
poorly sorted sediments (glaciers pick up all sorts of things and drop them at random)
✔✔mountain streams form: - ✔✔conglomerates
✔✔sand dunes - ✔✔sand stones
