Geology Unit 2
Terms
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- Porphyritic
- Rock has 2 different sizes of minerals. Cools slow then fast
- Types of Mechanical Weathering
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Frost Wedging
Pressure Release (unloading)
Biological Activity - Falls
- Sediment that falls from a mountain. Example: Rock fall. Frost Wedging is the most common cause.
- Escarpment
- Cliff- Caprock, Balcones
- Igneous (fire)
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Rocks formed after lava or magma has cooled.
Example: Granite; Basalt - Soil consists of:
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45% Mineral Particles
5% Organic Matter
50% Pore Space (air) - Weathering Rates Increase with:
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1. Water- brings chemicals into contact
2. Surface area- allows more chemicals to react - Varieties of Basalt
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1. Basalt- no holes
2. Vesicular Basalt- some holes
3. Scoria(ceous)- all holes - Pressure Release (unloading)
- expansion of rock due to removal of overburden, causing exfoliation domes. - Enchanted Rock, Stone Mt., GA. Independance Way, Wy, and Mt. Dun, Nz
- Laterite "brick"
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Very Rich in Al.
Develops in very wet climate
very poor soil due to leaching
*rainforests* - Biological Activity
- Mechanical Weathering caused by Plants/Animals
- Typical Soil Profile
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O Horizon- Top Soil/Grass
A Horizon- Sandy due to Leaching (zone of leaching)
B Horizon- Clay due to deposition (zone of deposition
C Horizon- weathered bedrock (spherodial weathering)
D Horizon- Solid/unaltered berock - Balcones
- separates the Edwards Plateau and the Blacklands prarie region- caused by faulting
- Pedocal
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Rich in Calcium
Develops in Dry Climate
Very rich soil due to lack of leaching
Western U.S. - Caprock
- Separates high plains from low plains- caused by erosion
- 3 Kinds of Mass Wasting
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1. Falls
2. Slumps
3. Flows - Humas
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Decayed Organic Matter
Compost-- - Frost Wedging
- When water seeps into cracks and freezes by 9%
- Talus
- Pile of rocks at the base of a cliff
- Types of Rocks
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Igneous
Sedimentary
Metamorphic - Factors Affecting Soil Formation
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Climate
Parent Rock
Time
Organic Activity
Slope (Topography) - Bowens Weathering Series
- Same as Reaction series; simply remember that those at the top weather faster than those at the bottom.
- Processes which lower the land
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1. Weathering (decomposition of Rock)
2. Erosion (removal of weathered rock)
3. mass wasting (mass transport of material downhill) - Weathering
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1. Chemical - rock chemically changes
2. Mechancial- rock physically changes - Sedminentary (to settle)
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forms when sediment is litihfied
ex: Shale, limestone, sandstone - Metamorphic (change)
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form where heat and pressure alters any rock
ex: Marble; slate - Distribution of Igneous Rocks
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Granite and Rhyolite- Continents
Andesite and Diorite- where continent meets sea floor (if plate boundry)
Gabbro and Basalt- sea floor (sometimes on continent) - How are igneous rocks classified?
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1. Composition (what minerals are found in the rock)
2. Texture:
a) Coarse (slow)
b) Fine (fast)
c) Glassy (very fast) - Acid Rain Destorys
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Buildings
Lakes
Trees - Pedalfer
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Rich in Al and Fe
Develops in wet climates
poor soil due to leaching
ex: Eastern U.S. - Humans make acid rain by
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1. Burning Anything (Co2 and rain)
2. Burning Coal- Sulfuric Acid
3. Burning Gas- Nitric Acid - Slumps
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sediment that slides- movement of soil in blocks along curved path
rock slide- sliding of rock along flat surfaces - Flows
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sediment that flows.
ex: creep- slowest flow
earth flow- thick mixture of sediment and water
Mudflow- fluid mixture of sediment and water (fastest) - The chemical weathering of orthoclase
- Orthoclase --- Kaolinite