Geography Test 4 Cheat Sheet
Mineral- inorganic naturally occurring substance with a distinct chemical formula and a distinct crystalline form
Rock-Aggregate of multiple grains of the same minerals
Earth’s crust is made up of 8 elements oxygen 47% silicon 28% Al 8% Fe 5% Calcium 3.6% Sodium 2.8% Potassium 2.7% Magnesium 2%
Every mineral has physical characteristics that aid in identification
Hardness scale 1-10 chalk (1) and diamond (10)
Luster-How shiny
Cleavage-how it breaks
Rocks are held together by a chemical bond
Most common is oxygen and silica SiO2 which has 92% of the Earth’s crust. Granite is silicate. CaCO3 limestone forms in warm waters
3 types of rocks:
Igneous- molten rock that has cooled and solidified
Felsic- rock that is light color and light weight
Mafic- heavy rocks are dark given it has a lot of metal
Sedimentary-derive from accumulated sediment fragment of rocks ex: limestone, clay, silt, sand, gravel, and boulder
Metamorphic- rock that has been changed and does not go into an igneous state
Limestone=marble
Sandstone-quartzite Fluvial process- River process Igneous(cools fast)- small crystal Igneous(cools slow)- large crystals Sedimentary- erodes, is transported, and later becomes rocks, sandstone and metamorphic (crystalline structure changed due to heat and pressure) Erosion- Process by which particles are separated from original site and deposit at a new site Arid and semiarid- wind and water are the main sources of erosion Geological Erosion- Sow uniform rate since the Earth was formed; wars down high places and builds up in low places A Slow uniform example is the Grand Canyon An example of deposition is the Mississippi Delta Region 3 Causes of Erosion Rain intensity- faster the velocity of the runoff the greater the erosion Erodibility- soil structure influences this Surface structure- roots also absorb the bad elements of items and provide a way for water to penetrate and leaves provide a good source for soil, the grass slows down the water Topography- Slope of the terrain greatly influences erosion Stream System- Excess water is carried to the ocean by streams and rivers Riparian- banks, floodplains, and wetlands are all associated with rivers Water falling as precipitation flows as runoffs or infiltration Ephemeral- Flows only after precipitation Perennial- water flows year around and sustained by groundwater Tributary- stream channel that flows into a larger channel Watershed- Entire area drained by a single river system or stream system (also known as a drainage basin) Divide- division between two drainage basins the largest river by drainage area is the Amazon River about 2300 sq miles Stream order- classification of a stream within a network of tributaries; a stream also refers to all moving water; a bayou is slow moving water Discharge Sediment load Bed and bank material If the material is silt and clay it is a narrow and deeper channel and if it is sand and gravel it is loose Stream load- Dissolved, suspended, bedload Dissolved- calcium and salts Suspended- Silts and Clay supported in the water Bedload- gravels too heavy for the water to bring up Stream transport- Suspension (moves along in the water) saltation (bounces off the bottom) traction (too heavy to pick up) Dendritic- tributaries don’t come across from each other, Rectangular- Straight line and 90 degrees by a fault or joint Radiated Star- flowing outward from the center point and tributaries less than 90 degrees Straight lines means that it was man made Meandering pattern is the most common how the stream order is in the lowlands it is like a slow conveyor belt Distributary-flows out Straight- beginning segments of a stream; the headwaters are where they start always eroding this is called headward (lengthening of a stream and its waters) Braided- happening with coarse materials like sand and gravel; very wide channel in arid environment; multiple channels are braided together Pools and Riffles- Regular shape and in shallow areas; storm flows dig out deep areas which become pools; manual stream flows and sediment deposited within the stream form riffles Floodplains- flat areas of sediment deposition which extend outward from the stream banks; forms as a flooding river overflows its banks and deposits sediments Terrances- high areas of previously abandoned floodplains; they occur overtime as the river downcuts and forms overview floodplains Stream Piracy (stream capture)- the headwater erosion of one stream can capture or pirate another stream Fossil water recharges very slowly Antecedent- River was there first Superposition- mountain was there first original ancient item was buried Glaciers- mass of ice that can flow as a solid Ice flows as a plastic solid either downhill from greater pressure to lower pressure (outwardly) more snow falls per year than melts. Snow under pressure becomes ice. When ice is about 100 ft the lower layer becomes a plastic solid Two factors for glaciers High latitude- 70-80 degrees North or South High elevation in the mountains Pleistocene epoch- ice ages Valley glaciers- high elevation going in a downward motion also known as an alpine glacier Continental glaciers (ice sheets)- Greenland and Iceland are examples of this and they flow in a radial direction 12000 ft We are between ice ages we should go back to ice in 6000 years conditions for this have been around for about 9 million years Fern- Snow that lasts over the summer and into the next year; helps form glaciers because of the cool summers Fernline- equilibrium line that separates the zone from where more snow falls and the zone where it melts, it represents the mass balances Positive mass balances- more receiving snow than melting snow Negative mass balances- more melting snow than receiving snow Zone of Accumulation- above the Fernline where it is received Zone of Sublimation- Below the Fernline where it melts Crevasses- Cracks in a glacier Erode- Transport- Deposit Till- Glacial Deposits Moraine- landform ridge of glacial deposit middle end and side River Valley- V Shape Glacial Valley- U Shape Cirque- French for Circus and it is the bowl shaped area on top of a glacier Tarn- lake inside of a cirque after the glacier is gone Arete- thin ridge between glacial valley Horn peak- Mountain peak which has cirques on several sides Aspect- Compass direction where a slope faces Esker- glacial deposits in a river in a tunnel underneath a glacier Kettles-As the glacier is retreating a big chunk of ice falls off and is partially buried; lakes are formed from a giant chunk of ice