EARTH SCIENCE at SPRING VALLEY HIGH SCHOOL
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UNIT III/B: SURFACE PROCESSES EROSIONAL-DEPOSITIONAL SYSTEMS
«1. Define and calculate gradient
a. - The steepness of a slope.
b. - Information measured at a specific location (elevation, temperature, wind speed, pressure, etc.)
c. Gradient can be calculated by the change in field value (ex/ difference in elevation) by the between the two points where the values were measured.
d. such as m/km must be used.
«2. Explain the factors that affect stream velocity and particle transport
a. Every steam and its branches make up a single system that collects all the runoff within a definite area called the drainage of the system.
b. A stream system consists of running , the land surface it drains, the it transports, and the energy used to drive it.
c. As the (slope) of the stream bed increases, the average velocity of the stream .
d. An increase in the (the volume of water flowing past a given point in a stream in a given amount of time) of a stream increases its average velocity.
e. Streams transport sediments in (dissolved salt), in (silt and clay), by bouncing ( ), and rolling or sliding (pebbles, cobbles and ).
f. The of the sediments that a stream can transport increases as the velocity increases (see ESRT p.6).
g. The total amount of sediment that a stream can transport increases as its discharge .
h. Sediments transported by streams tend to become as a result of abrasion.
«3. Describe the stages of stream development
a. Youthful streams carrying sediments down gradients can cut through solid bedrock.
b. When youthful, streams have V-shaped .
c. In the stage of maturity the valley of a stream . The stream ceases to cut through .
d. In old age, the stream develops a wide plain, across which it wanders in a series of curves, or .
e. Erosion occurs on the curve of a meander, where the water is .
f. Deposition occurs on the curve of a meander, where the water is .
g. A occurs when a meander has almost formed a complete loop, and the narrow neck of land is eroded in flood conditions, allowing the river to by-pass the bend.
h. - a crescent-shaped lake formed when a river meander gets completely cut off from the river.
«4. Compare & contrast factors which affect rates of deposition such as density, shape, size and energy loss
a. The processes by which transported materials are left in new locations are called (sedimentation).
b. Rock particles that are transported by erosional processes are called .
c. As the of a stream decreases, sediments will be deposited.
d. If all factors other than size are equal, smaller particles settle more in water than larger particles.
e. Very small particles, such as clay, may remain in water indefinitely.
f. If all factors other than shape are equal, flatter particles settle more in water than rounded particles.
g. If all factors other than density are equal, particles of higher density settle in water than particles of lower density.
«5. Describe horizontal and vertical sorting
a. Patterns of deposition result from a loss of within the transporting system and are influenced by the size, shape, and density of the transported particles.
b. When several events of deposition occur in quiet water, each involving a mixture of sediments, sorting will take place and graded beds of sediment will be formed.
c. As a stream gradually down, it deposits the larger, rounder, denser particles first, upstream. Smaller sediments are carried farther . The smallest particles are carried the farthest, eventually to the . This separation of sediment sizes from upstream to downstream is called sorting.
«6. Differentiate between deltas & alluvial fans
a. A is a fan-shaped deposit of sediment formed where a stream or river enters a quiet body of water, due a sudden in the velocity of the water.
b. An fan is a fan-like accumulation of sediment created where a steep stream slows down rapidly as it reaches a relatively flat valley floor.
«7. Explain glacier formation
a. A is a large mass of snow and ice that is moving because of .
b. Glaciers occur where the amount of is greater than the amount that melts over many years.
c. Glaciers are found only in regions and at altitudes.
«8. Recognize types and parts of glaciers
a. Valley or alpine glaciers are found in mountain areas where they usually follow valleys that were originally occupied by .
b. Ice sheets or continental glaciers exist on a much larger scale, covering most of and .
c. Front- The leading edge of a .
d. Crevasse- a in the glacial ice.
e. Tongue- At or near the coast, some glaciers flow directly into the and develop floating extensions, called "glacier tongues."
«9. Describe glacial motion
a. Glaciers flow slowly downhill and outward under the force of .
b. Research suggests that ice on the bottom of a glacier lubricates movement.
c. Glaciers move near the center, away from the of the valley walls.
«10. Understand the erosional & depositional effect of glaciation on landscapes
a. Glaciers leave behind valleys.
b. Most glaciers push, carry, and drag great quantities of known as till. The glaciers that shaped New York State must have moved huge amounts of unsorted sediment.
c. Glacial deposits contain mixed ( ) sizes of sediments from clay to huge (erratics). The great sizes of some erratics (like Indian Rock in Suffern) show the tremendous power of moving ice.
d. Glacial ice erodes solid rock by abrasion as the ice drags rocks over exposed .
e. erosion of New York's highest mountains shows that the ice was at least a mile thick.
f. Erratics traceable to bedrock exposures in the north show the general of ice flow. Some rock types are so distinct that their origins can be identified very confidently. Many boulders in our area come from the Adirondacks and .
g. erosion has produced characteristic features throughout New York State such as north-south valleys, and thin, rocky soils.
«11. Recognize glacial erosional/depositional features
a. Esker- a long, winding ridge formed when sand and gravel were deposited in meltwater beneath a glacier.
b. Moraines- deposited beneath, along the sides, and/or at the end of a glacier.
c. Kettle- a depression created by the melting of a large chunk of left buried in the ground by a retreating glacier. The ice prevents sediment from collecting; when the ice melts a lake or swamp may fill the depression.
d. - a long, canoe-shaped hill made of unsorted sediments and shaped by an advancing glacier. Drumlins point in the direction of glacier movement. The steep side of a drumlin faces in the from which the glacier came.
e. Glacial polish- a smooth polish on bedrock created when fine particles transported at the base of a abrade the bedrock.
f. Glacial striation- parallel grooves and scratches in bedrock that form as are dragged along at the base of a glacier.
g. Outwash plain- a smooth plain covered by deposits from water flowing from melting .
h. Glacial Valley (Glacial trough)- a U-shaped valley formed by erosion.
i. Hanging valleys- a smaller valley that enters a main valley at an well above the main valley's floor. Hanging valleys are often the sites of spectacular waterfalls.
j. Cirque- a deep, steep-walled hollow on a mountainside in which an alpine glacier forms. The walls and floor of the cirque are carved by glacial ice to form a shape.
k. Arête- a sharp narrow ridge between neighboring valleys.
l. Horn- a sharp, pyramid-shaped mountain peak where three or more cirques intersect near the summit. The Matterhorn of the Swiss was formed in this manner.
m. Fiord (fjord)- a long, deep, narrow inlet of the sea bounded by steep walls, generally formed by submergence of a glacially eroded valley. (In the book "Roadside Geology of New York" by Bradford B. Van Diver, the author documents: "The Hudson River has cut a narrow, 15-mile long gorge through the range between Peekskill and Newburgh that served as a channelway for ice erosion during Pleistocene glaciation. The gorge is a true , like those of the Norwegian coast, a glacially-gouged valley now invaded by the sea, and through which daily tides reach 160 miles inland to Troy!")
«12. Explain the effect of the Ice Ages on NYS
a. Layer upon layer of weathered till show that there have been several major periods of in recent geologic past. New York has been covered by thick ice repeatedly in the Pleistocene Epoch (1.6 mya). We live within a period of glacial/interglacial alternations.
b. The Ice Ages resulted in major ecological changes and very different plant and animal communities. The natural environment of New State might have looked like the tundra of northern Canada, Alaska, and Siberia.
c. Nearly all of New York State displays evidence of glaciation. Soils covering most of New York State are composed of weathered till. Only the Allegheny region and southern Island may have escaped covering ice.
d. Fossil and geologic evidence indicates periodic changes in level coinciding with the advancing and retreating ice sheets. Terrestrial fossils of the Pleistocene Epoch have been found on the continental shelf off Long Island.
e. Modern glaciers preserve samples of the atmosphere and dust from the distant . Modern studies of current glaciers are used to investigate prehistoric conditions on our planet. Air samples, pollen, dust and meteorites are regularly collected from the surface and deep within ( samples) major glaciers.
f. The Ice Ages left an abundance of sand and gravel as a natural resource. Sand and gravel are our most economically important geological resource in York State.
g. The Finger were formed by glaciation. So were the Great Lakes!!