MIDTERM HIGHLIGHTS Flashcards
ENDOGENIC
Geological processes that
originate inside of the earth’s crust.
(volcanism, plate tectonics, earthquakes, etc.)
EXOGENIC
Geomorphic processes that
originate at or near the earth’s surface.
(Mass wasting, weathering, erosion and deposition of
materials by fluvial, glacial, coastal, aeolian
processes)
THE TAGEDY OF THE COMMONS
Overconsumption of a shared resource (the Commons) results from individuals acting in
their own best interest.
Benefits go to the individual, but costs go the community
THE FIVE MINERALS THAT MAKE UP GRANITE
- QUARTZ
- ORTHOCLASE
- PLAGIOCLASE
- AMPHIBOLE
- MICA (BIOTITE, MUSCOVITE
FELSIC:
Feldspar + Silica
Light Colored
MAFIC:
Magnesium + Ferric (Iron)
Dark Colored.
PYROCLASTICS
a dense, fast-moving flow of solidified lava pieces, volcanic ash, and hot gases.
Intrusive (Plutonic) Igneous Rocks
Intruded by depth, exposed by erosion.
Magma cools slowly = large crystals.
Extrusive/Volcanic Igneous Rock
Extruded lava at surface and pyroclastic.
Lava cools rapidly = fine-grained crystals
SILLS & DYKES
Sills and dykes are formed when magma intrudes into rock.
Sills form where magma intrudes between layers, they run parallel to the layer.
Dykes form when magma intrudes into a rock along lines of weakness such as fractures and fissures.
PAHOEHOE
Is lava that in solidified form is characterized by a smooth, billowy, or ropy surface
AA
Is lava that has a rough, jagged, & spiny surface.
SILICA CONTENT
Controls how explosive a volcanic eruption will be.
The more silica, the greater the viscosity
SHIELD VOLCANO
Largest volcanoes. Formed from basalt. Gentle slope (5o - 12o).
Lava flows quickly and over great distances. Lava rivers and lava tubes common.
Some damage to infrastructure, not usually associated with loss of life.
CINDER CONE VOLCANO
A small volcano cone built of dry pyroclastic material of various size.
Smaller in size and shorter life span.
CALDERA VOLCANO
Volcanic eruption causes collapse of the cone into the magma chamber below and
collapse of a stratovolcano.
Calderas are some of the largest features (20 to 40 kms wide) and form from the most
violent and infrequent eruptions (10,000 yr frequency).
FLOOD BASALT
Very high volume eruptions of fluid (low viscosity) lava that floods large areas.
Repeated effusions from fissures produce layers of basaltic lavas to form lava plateaus.
Fed from mantle plumes.
STRATOVOLCANO OR COMPOSTITE VOLCANO
Intermediate in size. Variable slope angles.
Volcanoes of the “Ring of Fire” (i.e. subduction zones ) are composites. Most commonly
made of andesitic lava.
These volcanoes reflect alternating compositions of magma and the highly variable deposits that result.
Deposits can alternate between lava flows and tephra deposits.
LAHAR
volcanic debris flows or mudflows (slurry of water and mud) resulting from rapid
melting of snow or glaciers near the summit.
LITHIFICATION
COMPACTION & CEMENTATION
STRATIFICATION
the layering that occurs in most sedimentary rocks and in those igneous rocks formed at the Earth’s surface, as from lava flows and volcanic deposits
RIPPLE MARKS
– Structures formed by wind or water
– Sediments accumulate downslope (lee side)
– Symmetrical ripples
* Bidirectional current
– Asymmetrical ripples
* Unidirectional current
TILTED DEPOSITS
May have once been horizontal but then deformed or uplifted.
CROSS-BEDDING
Sediments deposited on an angle.
Tends to happen in places with flowing water or blowing wind in one direction.