| Term | Definition |
|---|
| glacier definition | thick mass of compacted and re-crystalized snow. forms on land and shows from form of movement. |
| continental | largest glacier, 1000 miles wide and deep. only two on earth today covering antarctica and greenland. |
| alpine | smaller glacier. less than 100 mi wide/deep. over 1000 found around the world. |
| icecaps | medium size. about 10 around the world. found in high plateaus like tibet. |
| formations | glaciers can take at least 100 years to form. no ice ages now. |
| firn | compacted snow' very icy and formed when snow doesn't melt in summer time. |
| glacial ice | compacted/re-crystalized firn. light blue color. heavier than ice and an icebergs made of glacial ice. |
| glacial movement | most of the time, glaciers move slowly . few inches a day. |
| basil sliding | glacial slips/slides on a think layer of mud at the bottom of a glacier. |
| surges | any quick/sudden movement of glaciers, happens with alpine glaciers. expecially during the summer (melting season). |
| zone of fracture | upper 1/3 of a glacier where the ice is very brittle & will crack as the glacier moves. |
| crevasses | deep cracks found in the zone of fracture about 200-300 ft. deep. -especially dangerous to mountain climbers. |
| zone of flow | the lower 2/3s of a glacier, where the ice will bend as the glacier moves, like thick caramel/molasses. |
| zone of accumulation | upper half of a glacier, usually at a higher elevation where snowfall is greater than melting. |
| zone of wastage | lower 1/2 of a glacier where melting is greater than snowfall. |
| advancing glacier | any glacier that's growing in size in 2009, there are few advancing glaciers. |
| retreating glacier | any glacier that's shrinking in size. 2009: most are retreating, meaning the climate is warming up. |
| calving | process of forming icebergs. spectacular and loud process & occurs when glaciers flow into the ocean. |
| fjord | u-shaped valley that's underwater. they're formed when a glacier retreats from a coastline. famous in norway, sweden &alaska. |
| striations | very small scratches found in the bedrock produced by the erosion of a glacier. |
| grooves | same as striations; formed by the erosion of a glacier but are much much bigger. kelley's island: lake erie ; famous for glacier grooves. |
| quarrying | when a glacier breaks off and crushes large boulders as it goes over a cliff or a ledge. |
| roche montonnee | rock formation formed by quarrying action in the glacier: famous in yosemite national park. |
| drift | term referring to any gravel or boulders thats left behind after a glacier melts. sr. rock: glacial drift called a glacial eratic. |
| outwash | type of drift that's found in layers & produces a very flat landscape like what's found in w. ohio. |
| till | also drift but it's unlayered; produces a hilly landscape. KHS is built on glacial till. |
| moraines | a ridge of rill. they form long hills and are found anywhere there used to be a glacier. |
| alpine features | horn : sharp mountain peak. tourn : mountain lake. pater : two or more mountain lakes. U shaped valleys. hanging valley. "waterfall" arete : long & sharp mt. peak. |
| continental features | kame: made of glacier till. kettle: depressents that have water (geauga/punderson). marines: hills of ridges of till. drumlin: teardropped shape hill. esker: made of sand and is like a marine. |
| ice ages. | periods of time where all the glaciers are advancing. many ice ages in history of earth only takes a 10 degree drop in temperature to go into the ice age. |
| interglacial features | warmer periods of time btwn ice ages currently are living in an interglacial period and the earth should naturally warm for the next 80,000 years. |
| ice cores | tubes of glacial ice that are drilled and removed from a glacier in order to study past climates. |
| milankovitch cycle | theory that says every 100,000 years the earth naturally cools down and goes into an ice age caused by the wobble of the earth's axis and change of shape of earth orbit. |
| glacial advances | four glaciers that have come down from canada during the past half million years. each advance is named after a state with most evidence. (nebraska, kansas, illinois, wisconsin) |
| glacial map: ohio. | 2/3 covered by glacier during each one. |
| structural geologist | looks at surface map. draws in rock layers underground highest paid find oil and gas. |
| compressant (type of stress) | rock layers are pushed tgthr occurs when large crustal plates collide. |
| tensional (type of stress) | pulled apart causes rock layers to break and move along fault lines, produces rift valleys. |
| shear (type of stress) | multidirectional stress produces most distractive earthquakes on the earth. |
| fold | bend in a rock later caused by compressional stress, high temperature and pressure. |
| anticline | a fold that bends upward |
| syncline | a fold that bends downward |
| recumbent fold | anticlines and synclines combined tgthr. |
| dip | angle a rock layers tilted from horizontal, the rock beneath KHS is dipping at about seven degrees. |
| strike | always measured at ninety degrees to the dip & is measured in a north/south or east/west direction. |
| rules for mapping folds | 1. oldest rock layers will always be found at the center of an anticline. 2. youngest rock layers found at center of a syncline. 3. never change the thickness of an underground rock layers. |
| fault | a break in the rock layers along which there must be movement on each side. there are no surface faults in ohio. |
| hanging wall | also an old gold-mining term that refers to the side of the fault that's above your head and you'd hang your lantern on that side of the fault. |
| footwall | also an old gold-mining term and it's the side of the fault your feet would be on if you tunneled/dug into the fault. |
| fault planes | middle of the fault and it's the imaginary line that divides hanging wall and foot wall. |
| normal fault | when the hanging wall side moves down compared to the footwall side. always caused by tensional stress. |
| reverse fault | when the hanging wall side moves up compared to the footwall caused by compressional stress. |
| transcurrent fault | a horizontal movement fault so there's no hanging wall or footwall. san andreas fault in california is a famous one. |
| rift valley | special type of valley that's produced by tensional stress & to normal faults. |
| isostasy | balance of the earth's crust which means if one area, the cause is sinking, another area, the crust is rising. isostatic rebound - man cause for earthquakes in ohio. |
| formation of oil | oil is a gross smelly very thick liquid, almost pitch black in color. formed by the decay of microscopic marine life. millions of years of heat and pressure to produce a chemical. |
| anticline or dome oil trap | richest and most productive of traps. produce millions of gallons of raw oil. |
| faults | second most productive of traps. when we find oil nxt to normal/reverse faults. |
| stratagraphic | most common oil map in NE Ohio also produces the least amount of oil. |
| density scan | when a structural geologist calculates the density of the surface rocks looking for a value of above 26g/cm. ohio passes this test. |
| core sampling | when they look for certain fossils at the surface and underground that are usually found with oil deposits. example: pelecypod. ohio passes this test. |
| seismic blasting | when structural geologists set off a series of dynamite charges and record bound back time of the sound waves made by the explosions. ohio fails this test. |
| oil wells. | 1. the first well was drilled in PA and oil was struck @ 100 ft down. 2. 2009: average cost for drilling an oil well: $7 mil. av. depth; 7000 ft. 3. a gusher is when oil pours out of an oil well under high pressure. it's a bad thing because you lose and pollute the landscape. |
| fractional distillation | process of boiling the raw oil that comes out of the ground in order to make something useful w/it. like gasoline, kerosene, diesel fuel, motor oil, asphault & cosmetics. -takes place @ an oil refinery which employs 1000s of people but is done away from civilization. |
| coal | black sedimentary rock full of a chemical compound called hydrocarbons and since the US is the saudi arabia of coal, we burn it by the tons everyday to produce electricity. |
| four grades of coal | anthrocite: burns clean - very hot. bituminous and sub-bituminous : US burn these two. lignite : worst grade - smokes - burns cooler. |
| underground mining | when we dig mine-shafts or tunnels in order to reach the coal considered very dangerous because of cave-ins, explosions & the black lung disease. |
| strip mining | preferred way to mining coal and it's when we dig a huge pit to reach the coal. it's big drawback is that is leaves a large erosional scar on the earth. |
| scrubbers | a method used to remove sulfur from coal so it burns clearer and you don't produce acid rain. the method is expensive and you pay for it in your electric bill. |
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