GEG 111 Exam 4 Harper College

Tsunami - A seismic sea wave, travelling at high speeds across the ocean, formed by sudden motion in the seafloor. Causes: Sea-floor earthquakes, submarine landslides, and eruption of an undersea volcano Physical Structure of the Ocean - Basic structure consists of 3 horizontal layers: 1-Mixing zone 2-Thermocline transition zone 3-Deep cold zone Mixing Zone - warmed by the sun and driven by the winds Thermocline transition zone - Temperature decreases with depth Deep cold zone - Temperatures are generally near 0 degrees Celcius but waters do not freeze because of the lower freezing point of seawater. Spring tide - The highest tidal range, which occurs when the Moon and the Sun are in conjunction(at new moon) or in opposition(at full moon) stages. Neap tide - Unusually low tide range produced during the first and third quarters of the Moon, with an offsetting pull from the Sun Fringing reef - grow near the coastline around islands and continents. They are separated from the shore by narrow, shallow lagoons. Barrier reef - Form parallel the coastline but are separated by deeper, wider lagoons. At their shallowest point they can reach the water's surface forming a "barrier" to navigation. Atoll - Are rings of coral that create protected lagoons and are usually located in the middle of the sea. Coral bleaching - Process through which corals expel their nutrient supplying algae, turning white, leading to increased mortality. Possible causes include very warm water, pollution, disease, sedimentation, changes in ocean salinity, and increasing oceanic acidity. Eolian Processes - Geomorphic (Earth shaping) processes caused by the wind. -Air acts as an agent of erosion and deposition. -Consistent local wind can prune and shape vegetation. Alpine glacier - Refers to glaciers that form on mountains Ice sheets - Refers to extensive masses of ice that may occur on a continental scale. -These cover 81% of Greenland and 90% of Antarctica Ice caps - A roughly circular glacier that covers an area less than 500,000 Km^2 Ice fields - An elongated glacier that forms over a mountain region. Glaciel Drift - All material carried and deposited by a glacier. Features associated with Alpine glaciation - -Cirque -Horns -Aretes Cirque - A glacier formed when snow fills a bowl-shaped depression at the top of a valley. Horns - A pyramidal peak that results from several cirque glaciers erode towards each other. Aretes - A narrow ridge that is formed when adjascent glaciers erode towards one another. Features associated with continental glaciation - -Drumlins -Kettles -Kame -Esker Drumlins - Hills of deposited till that are streamlined in the direction of ice sheet movement, with the blunt end upstream and the tapered end downstream. Kettles - A depression that forms when an isolated block of ice persists in a ground moraine or outwash plain; as the block melts the hollow may be filled with water. Example: Lake Geneva, Wisconsin Kame - A small hill of poorly sorted glaciofluvial sand and gravel Esker - Elongated snake-like deposits of glaciofluvial gravel, thought to have been formed from meltwater streams that flowed underneath glaciers while they are stagnant. Pedology - the study of soils in their natural environment O-Horizon - Organ matter A-Horizon - Top soil/dark color E-Horizon - eluviation layer B-Horizon - illuviation layer C-Horizon - Beyond reach of roots R-Horizon - bedrock