APES Geology Flash Cards

Geosphere

Core: Interior of the earth composed of hot metal (iron), solid center, semi fluid outer 2,900-5,000 km in diameter
Mantel: Surronds core, much less dense, high concentration of light elements ( O2, Fe, Si, and Mg), 2,900 km in depth

Crust:  cool, lightweight brittle rock that floats on mantle ( oceanic crust is more like the mantle but has more Si while continents are thicker, lighter regions of crust rich in Ca, Na, K and Al. 

Plate Tectonics #1

Originally called continental drift

Tectonic Plates – large pieces of land brokena nd moved by huge convection currents on the soft upper layer of mantle.

Magma: molten rock underground Lava: molten rock on Earths surface

Divergent plate boundaries – seperation of plates, magma that gets pushed up from mantle through cracks in the oceanic crust pile underwater create ocean ridges. Huge underwater volcanoes are formed, such as the mid ocean ridge

Plate Tectonics #2

Divergent boundaries can occur on land too causing a rift valley ex. Kenya, Africa

Convergent Plate boundaries – when plates collide

land-land collisions – non volcanic mountain ranges are pushed up ex Himalyia Mountains

Ocean-Land collisions – ocean plate is subducted and volcanic mountain chains are formed on the side of the land adjacent to the ocean ex. Andes Mountains 

Plate Tectonics #3

Ocean-Ocean collisions – one of the ocean plates are subducted causing a chain of volcanic islands are formed claled an island arc ex. Japan, Indonesia. Hawaii however is caused by a hot spot: a single plume of pulsing magma creates an island chain as the plates move over it. 

Earthquakes are caused by grinding and jerking as plates slide paste each other

Ring of fire is the area surronding the pacific ocean rich in earthquakes and volcanoes

Rocks and Minerals #1

Mineral – naturally occuring inorganic solid element or compound with unique chemical composition and regular internal crystal structure

Rock – a solid, cohesive, aggregate of one or more minerals
Rock Cycle – any rock can turn into any other rock type

Igneous Rocks – made by melting and subsequent cooling of molten rock. Magma that reaches earth surface cools quicker and creates basalt or rhyolite. Rock are fine grain. Magma that cools in subsurface has coarser, intergrown crystals and forms granite and gabbro.  

Rocks and Minerals #2

Sedimentary Rock: Made three different ways
Clastic Rock – formed when weathered sediments are fcemented togetehr ex. conglomerate

chemical sedimentary rocks – form when solid rock is precipitated from solution ex. rock salt

Organic sedimentary rocks – made of organic matter ex. coal

Weathering – exposure to air, changing temps and chemical reactions cause breakdown of durable rocks. (Mechanical weathering – physical breaup of rocks into smaller particles w/o a change in chemical composition.) 

Rocks and Minerals #3

Chemical weathering – selective removal or alteration of specific components that leads to the weakeneing and disintegration of rocks ex. oxidation and hydrolysis. 

Metamorphic Rocks: preexisting rocks that have been modified by heat, pressure. They can form from contact metamorphism ( proximity to magma) or regional metamorphism ( burial deep in the crust). These rocks often hold the most economically important minerals such as talc, graphite and gemstones. 

Geologic History
Eras – Paleozoic ( age of fish), Mesozoic ( age of reptiles), Cenozoic ( age of mammals).Mass extinctions are the end of an era.
Economic Geology and Mineralogy #1
Economic Mineralogy: the study of minerals that are valuable for manufacturing and are important parts of domestic and international commerce. Metal bearing ores are most economic minerals. 
Most valuable crystal resources are everywhere, just hard to reach
Economic geology and mineralogy #2

Greatest consumed metals – iron, aluminum, magnanese, copper, chromium and nickel 

Non Mineral Resources – gemstones, mica, talc, asbestos, sand, gravel, salts, limestone and soils

Sand and gravel have highest economic value of nonmetals and metals for roads and cement

Evaporites – materials deposited by evaporation of chemical solutions. Are mined for halite, gypsum and potash. Found at 97% purity.. Halite is for water softeners and as road salt and refined as table salt. Gypsum is used for wallboard and potash for fertilizers

Economic Geology and Mineralogy #3

Strategic metals and minerals: resources a contry uses but cannot produce itself. 

Less developed countries sacrifice the environment to mine and become producers of resources other countries need. 

Ore – a rock in which valuable or useful metals occurs at a concentration high enough to making mining it economically attractive

Copper – econimcally vaiable concentration is close to 1 percent

Gold and others are close to .00001 percent.

Economic Geology and Minerals #4

Placer Mining – process in which native metals deposited in gravel of steam beds are washed out hydraulically. Aquatic life and stream beds destroyed. 

Strip Mining and open pit mining – materials removed from large, deep surface mines by big equipment. Land is left barren and water is polluted, 50% of US coal is strip mined

Heap Leach extraction – gold separated from ores using alkaline-cyanide solution which is extremely toixc to environment in the invvitable leaks into the ground water

Economic Geology and Minerals #5

Underground tunnels – used to reach the deepest deposits 

Mountaintop removal mining – mountain removed from coal which devastates ecosystems 
Hazards – can cause explosions from natural gas,  rain and ground water absorb toxic chemicals, tailings of uranium can spread through the wind

Controlling Mining

1977 Federal surface mining control and reclamation act – requires better restoration of strip-mined lands, especially farmlands, $1000 per acre

Smelting – roasting ore to release metals, major source of air pollution

Ducktown Tennesse – mid 1800’s mining companies extracted copper with huge open- air wood fires which acidified soil and poisoned vegetation 

Recycling
Recycling aluminum consumes one-tweentieth fo the energy of extracting new aluminum (bauxite). Aluminum used for construction and transportation. Substituting metal pipes for plastic pipes. Steel replaced by polymers.   More fuel efficiency in newer vehicle models.
Earthquakes

Earthquakes – sudden movements int he earths crust that occur along faults where one rock mass slides under another 

Tsunami – giant seismic sea swells that can move at 1,000 km/hr or faster from center of an earthquake 

Pyroclastic flows are denser than air mixtures of hot gases that move faster than 100 km/hour and destroys towns such as St.Pierre on the caribbean island of martinique