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Geography Unit 3

STUDY
PLAY
marble
Which rock results from the metamorphosis of limestone?
Mt. St. Helens
What Volcano is an example of a stratovolcano?
Lahar
what is not a landform created by glacial activity
Biomes
Areas of similar vegetation, climate, soil, topography
Low Latitude rainforest
Equatorial Region: Wet Equatorial Climate. Consistent rainfall, high temperatures. Broadleaf Evergreen Trees. High productivity and High species diversity
Sub-Tropical Evergreen Forest
Southeastern US and Southern Asia. Broadleaf and/or needleleaf. Relatively few species of trees. Two Layers.
Monsoon Forest (Tropical deciduous forest)
Boarders tropical rainforest, transitional to less wet climates. Mix of evergreen and deciduous trees. Less diversity, lower biomass, 2 layers of vegetation, dense understory compared to Tropical Rainforest.
Midlatitude Deciduous Forest
Extensive on N. Hemisphere continents. Tall broadleaf trees, dense canopy.
Needleleaf Forest
Pacific Northwest and Boreal Forest (aka Taiga)-NA and Eurasia. Severe mid latitude climates. Evergreen Needle leaf and evergreen deciduous.
Schlerophyll Forest
Small areas in mid-latitudes. Dry Summer, Wet Winter. Sclerophyll-thick, leathery leaves. Chaparral-Dense, fire adapted shrubs.
Savanna
Tall grasses. Big game. Serengeti plains. Wet, dry, and wildfire season.
Grassland
Steppe (Asia), Pampa (Argentina), veldt (South Africa), prairie (N. America). Perrenials. Migratory ungulates.
Desert
Drought resistant plants vs drought evading plants. Nocturnal, Burrowing mammals.
Tundra
Cold desert of grassland. Moisture scarce. Dwarf grasses. Migratory birds, animals.
geomorphology
the study of landform (characteristics, origins, development). It focuses on the surface of earth.
Landform
Individual topographic feature on the surface of the earth that can range in size. (Mountains, peninsula, sand dune)
Earth's Crust
<1% of Earth's Volume. 0.4% Weight. 8-40 miles thick. 47% Oxygen, 28% Silicon, 25% metals and bases.
Igneous Rock
Molten Rock source. Cools slowly=big crystals. Cools fast=small crystals. Intrusive and Extrusive. (transform from melting. Magma melts and forms rock when it cools)
Sedimentary Rock
Deposited on surface. Layering=strata. (transform from weathering and erosion. Compacted and cemented)
Metamorphic Rock
Altered igneous or sedimentary rock. Form deep in the earth. (transform from Heat and Pressure.)
Extrusive Rocks (igneous rock)
Spewed out. Cooled on earth's surface. Rapid cooling. Crystals too small to see with naked eye.
Intrusive Rocks (igneous rock)
Cooled below Earth's surface. Slow rate of cooling. Large crystals, seen with naked eye.
Mechanical Formation "Clastic" (sedimentary rock)
Weathering. Clastic-Formed from Fragments of other rocks.
Chemical Formation (sedimentary rock)
Precipitation of soluble materials (saltwater). Shell Accumulation.
Organic Formation (sedimentary rock)
Tissues of plants and animals. Solids-Peat and Coal. Liquids-petroleum. Gasses-natural gas.
Diastrophism (internal)
Deformation of the Earth's crust. Solid not molten material. Folding and Faulting.
Volcanism (internal)
Volcanoes
Weathering (external)
Processes that cause rock to disintegrate
Mass Wasting (external)
Gravity induced downhill movement of soil, rocks, and regolith (fractured rock). Soil Creep, earth flow, debris flows
Erosion/deposition (external)
Wearing away of soil
Faults
Extreme folds. Broken rock. Displacement. Horizontal and/or vertical movement.
Age of Crust
Ocean <60 million years. Continent >1 billion years. Age increases with distance from oceanic ridges. Oldest ocean crust is near the trenches.
Lahar
Volcanic mudflow. Ash and Pyroclastic materials. Mobilized by rain or melting snow. Rapidly moving.
Lateral Blast of a Volcano
Uncorking of pressure. Rock, ash, hot gases. Magmatic material-cryptodome exposed. 670 mph!
Pyroclastic Flows
Hot, incandescent mixtures of volcanic fragments and gases. Sweep along close to the ground. 450 mph! Lethal and destructive (pompeii).
Ash (tephra) Deposition
540 Million tons. 22,000 square miles. Football field piled 150 miles high
stratovolcano
Mt St Helens. Tall, steep sided cones. Felsic (rhyolite and andesite) lava, viscous.
shield volcano
Hawaiin Islands. Occur at mid-ocean ridges. Highly fluid. Slow eruptions are slow, broad expanse of lava flow. Forms low "shield." Little pyroclastic material.
Nuees Ardentes
french for glowing clouds
Landforms created by frost action
Talus Cones and "Felsenmeer"-Boulder fields
Landforms created by Frozen Ground
Patterned ground, pingo
Niche Formation
Salt Crystal Growth. Dry climates. Groud water moves through rock via capillary action. Salts deposited. Crystals grow.
Physical Weathering
Produces Regolith (fractured rock), frost/ice action (Talus cones and Felsenmeer-boulder fields), Salt Crystal Growth, Unloading, wind, wedging by roots
Unloading
In pressure release, overlying materials (not necessarily rocks) are removed which causes underlying rocks to expand and fracture parallel to the surface
Chemical Weathering
Hydrolysis and Oxidation. Acid Action. Changes strong rocks into weak ones, rich in clay minerals and oxides, warm, humid climates.
Acid action
Carbonic acid (CO2 +H20) Esp carbonate rocks
Soil Creep (Mass Wasting)
Slow movement of soil and regolith.
Earthflow (Mass Wasting)
Humid climates, water saturated soil, faster movement: hours. Too much water on the golf course!
Mudflow/Debris Flow (Mass Wasting)
Liquid mud flow caused by rapid precipitation or snow melt. Follows stream courses and moves rapidly. Ex: Alluvial fans
Natural Hazard
Unexpected or uncontrollable natural event of unusual magnitude that threatens the activities of people or people themselves
Natural Disaster
natural hazard that ACTUALLY resulted in widespread destruction of property or caused by injury and/or death
Tsunami
Japanese for harbor wave. Waves with very long wavelengths
Causes of Tsunamis
Sudden rise or fall of earth's crust under or near ocean. Displaces water column. Creates rise or fall in level of ocean above. Size and energy dissipates with time and distance from source. Volcanic activity and mudslides can also cause tsunamis.
Physical factors that affect tsunami severity
speed affected by water depth (500 mph in 20,000 ft water). Shallow water, speed slows but energy remains same. Energy dissipates slowly from source. When it reaches shore its modified by reefs, beaches, and land.
Human factors that affect tsunami severity
TWS. Tsunami Warning System. 26 member countries in the pacific. Seismic and tidal monitoring.
Glaciers
Large, natural accumulations of ice that FLOW/SLIDE downhill or from center of accumulation. They leave distinct geomorphic features.
Alluvium
loose, unconsolidated (not cemented together into a solid rock) soil or sediments, which has been eroded, reshaped by water in some form, and redeposited in a non-marine setting
Colluvium
loose bodies of sediment that have been deposited or built up at the bottom of a low-grade slope or against a barrier on that slope, transported by gravity.
Pleistocene Glaciations
Pleistocene (last 1.5 million years). Alternating glacial and interglacial times (100,000 year cycle).
Holocene Glaciations
Last ~10,000 years. Relatively ice free and constant conditions.
Laurentide Ice sheet
Canada sliding downward through the united states
Continental ice sheets
non-mountainous areas, blankets of ice
Mountain Glaciers
smaller, high elevation glaciers
Accumulation
addition of ice by new snow
equilibrium
additions and losses equal
alblation
loss of ice through melting, evaporation, and sublimation
Moraine
any glacially formed accumulation of unconsolidated glacial debris (soil and rock) which can occur in currently glaciated and formerly glaciated regions, such as those areas acted upon by a past glacial maximum.
subduction
one tectonic plate moves under another sinking into the earth's mantle