Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Topic 8
Weathering and Erosion
| Term | Definition |
|---|---|
| Abrasion | A process of wearing away of earth materials by an agent of erosion. |
| Agent of erosion | Erosional-depositional systems that remove earth materials, transport them to new locations, and deposit sediments. Agents of erosion include: running water, glaciers, wind, waves and currents, groundwater, turbidity currents, gravity, and humans |
| Alpine glacier | Also called mountain glacier or valley glacier; a large body of ice that forms near the summit of a mountain and erodes existing river valleys. |
| Annular pattern | A river drainage pattern that forms a series of circles. An annular pattern generally indicates underlying rock structure that has a series of rings consisting of rocks with different resistances to weathering. |
| Bedrock | The solid rock that is found beneath sediments or soil. |
| Cave | An irregular underground void or tunnel formed by groundwater. Many caves and caverns are formed when carbonic acid in groundwater dissolves limestone bedrock. |
| Chemical weathering | The decomposition of rocks or minerals as a result of chemical reactions that occur at or near the Earth’s surface. Chemical weathering produces materials that are stable at the Earth's surface. |
| Cobble | A rock fragment, soil particle, or sediment having a diameter in the range of 64 mm to 250 mm. A fragment that is larger than a pebble and smaller than a boulder. |
| Continental ice sheet | Continental glacier. Large masses of ice that cover major portions of a continent. During the Pleistocene Ice Age, large glaciers covered much of North America. Today, continental ice sheets are found on Antarctica and Greenland. |
| Cut bank | Also called undercut bank; the eroded bank on the outside of a river meander. As the river flows around the meander, the water's velocity increases and erosion occurs. |
| Delta | A feature that forms where a river enters into a large body of water and deposits sediments. Some deltas, such as the Nile Delta, look like the Greek letter (Δ). Other deltas, such as the Mississippi Delta, look like a bird’s foot. |
| Dendritic drainage pattern | An arrangement of surface drainage (streams) that form a branching or tree-like pattern. A pattern of rivers that forms in regions having basically horizontal rock structure and uniform resistance to erosion. |
| Density | The property of matter that indicates the mass per unit volume. Density provides an indication of the packing of the particles of matter. Density is calculated by the equation: |
| Deposition | The process by which sediments settle out of any natural agent. Agents of erosion produce deposits of transported soil. The precipitation of minerals from sea water can form layers of non-clastic sedimentary rocks. |
| Downcutting | Erosion of the bed of a river. Erosion that deepens a V-shaped valley. |
| Drumlin | Reworked glacial till that often forms low oval-shaped hills that have their steepest side in the direction from which the glacier advanced. |
| Erosion | The breakdown and removal of earth material by specific agents, such as gravity, ground water, running water, ice, wind, wave action, turbidity currents, and human activities. |
| Erosion rate | The rate at which rocks or sediments are removed by an agent of erosion. |
| Escarpment | A long steep slope or cliff that faces one general direction. Steep slopes formed by erosion or faulting. |
| Eskers | Ridges of sorted sediments deposited within streams flowing beneath the melting glacier. Streams flowing within or below glaciers or the ridges of sediments they deposit. |
| Finger Lakes | Long narrow lakes that form when glacial valleys become blocked and fill with water. |
| Floodplain | The relatively flat area along both sides of streams that fill with water when streams overflow their banks (floods). |
| Freeze-thaw/Ice action | A form of physical (mechanical) weathering that occurs in areas where temperatures rise and fall above freezing. When liquid water in cracks in rocks freezes the water expands applying pressure to the rock. |
| Glacial deposits | Drift. Any rock material or fragments left by moving ice. Glacial deposits are often unsorted and angular. |
| Glacial erosion | The wearing away and/or removal of soil, rock, or earth materials by large masses of moving ice. |
| Glacial till | Unsorted and unstratified material deposited by a glacier. |
| Glacier | An agent of erosion; a large mass of moving ice that flows as a result of its own weight. Glaciers are classified as: valley, piedmont, and continental. |
| Gradient | The slope or rate of change on a graph or field diagram. The closer the isolines on a map, the steeper the gradient. |
| Gravity | The force of attraction between the centers of mass of the Earth and any object in, on, or above the Earth. The force that drives many erosional systems. |
| Ground water | Fresh water that is found between particles of soil or cracks in rocks. Water that moves towards and/or becomes part of the zone of saturation. |
| Kames | Small hills of unsorted sediment deposited at the base of waterfalls formed by streams flowing over the edge of a melting glacier. |
| Kettle lake | Kettle-hole lake. A lake that formed as the result of a block of ice that detached from a glacier and was partially covered with glacial deposits. When the ice melted, a depression formed and filled with ground water. |
| Kinetic energy | Energy of motion. The kinetic energy of a particle or system is proportional to the product of the mass and square of the velocity. An increase in the kinetic energy of an erosional system results in an increase in erosion. |
| Landslide | The movement of a mass of soil, rock, or both, down a slope. During a landslide, the material tends to move as one piece. |
| Limestone | Any sedimentary rock that is composed primarily of calcium carbonate (lime). Limestones can form by deposition of lime muds, precipitation of crystals, or by the secretions of living organisms. |
| Mass movement/mass wasting | The down slope movement of rock or soil caused by gravity. |
| Meander | A bend or curve of a mature river flowing on its flood plain. |
| Meandering pattern | A pattern of stream flow in which the river forms a series of bends (meanders) or loops (oxbows). |
| Moraine | Sediment that has been or is being transported by ice; unsorted and generally angular sediments that have been transported and deposited directly by glaciers. |
| Outwash plain | A feature with relatively flat or rolling topography formed from sediments deposited by streams flowing from a melting glacier or ice sheet. |
| Pebble | A rock fragment, soil particle, or sediment having a diameter in the range of 0.2 cm to 6.4 cm. A rounded fragment that is larger than a sand grain and smaller than a cobble. |
| Physical weathering | The disintegration of rocks and minerals into fragments without any chemical changes. Processes of physical weathering include: frost action, pressure unloading, and possibly thermal expansion and contraction. |
| Point bar | A deposit of sediment that forms on the inside of a meander. As the water flows around a meander, the velocity decreases on the inside of the bend and deposition occurs. |
| Precipitation | Weather phenomena of rain, snow, sleet, and hail. |
| Pressure belts | Bands of pressure that form parallel to the equator as a result of rising or descending air. Low pressure belts at the equator and higher latitudes are associated with humid climates. |
| Radial drainage pattern | A pattern of rivers and streams that seem to spread out (radiate) from a central elevated region. |
| Rate of change | Slope. The amount of change that occurs divided by the time required for the change to occur. Any rate of change can be found by using the equation: R=quan/time |
| Rock abrasion | The wearing away of rock material as it is transported in an erosional system. The rough, jagged edges generally break off first, as the material becomes rounder and smoother. |
| Running water | Stream flow or rivers. The movement of water in a channel or valley. |
| Sand | A rock fragment, soil particle, or sediment having a diameter in the range of 1/16mm to 2mm. Sediment or soil particle that is larger than silt and smaller than a pebble. |
| Sand dune | A mound, ridge, or hill, formed by wind-blown sand. Types of sand dunes are classified on the basis of their shape and orientation to the prevailing wind direction. |
| Sandblasting | A process in which wind-blown sand grains abrade materials; sand blasting by the wind can form sediments with triangular tops and rounded bottoms called ventrifacts. Sandblasting and often leaves surfaces pitted and frosted. |
| Sandstone | A clastic sedimentary rock composed primarily of sand grains that are held together by a natural cement. |
| Sediments | Any solid material that is transported and deposited by an agent of erosion, chemically precipitated from water, or secreted by an organism. |
| Side cutting | A form of erosion in which rivers cut their banks. Side cutting results in the formation and development of flood plains. |
| Silt | A soil particle or sediment having a diameter in the range of 1/256mm to 1/16mm. An accumulation of particles that are larger than clay and smaller than sand. |
| Sorted sediments | Deposits that are generally separated by size, shape, or density. Streams sort sediments horizontally while turbidity currents sort sediments in a vertical direction. |
| Stream channel | The portion of a stream with the greatest depth. The path along which a stream is currently flowing on a flood plain. |
| Stream discharge | The rate of stream flow expressed in units of volume per unit of time, for example, cubic meters per second. |
| Stream drainage pattern | The general arrangement of surface flow in a watershed. The pattern may indicate underlying rock structure. |
| Stream erosion | The wearing away and/or removal of soil, rocks, or earth materials by running water. |
| Stream velocity | The rate of flow for a stream or river. The stream velocity is one factor that determines the kinetic energy and erosional ability of a stream |
| Striations | Parallel scratches, grooves, or markings. |
| Trellis pattern | A form of rectangular river drainage pattern in which the streams join each other at nearly right angles. This pattern generally indicates an underlying rock structure consisting of jointing, folding, or faulting. |
| Turbidity current | Density current composed of a mixture of sediment and water. An agent of erosion that removes material from the continental margins and deposits sediments in graded beds on the deep ocean floor (abyssal plain). An agent of erosion that acts under water |
| Turbigenic sediments | Material that is deposited as the result of a turbidity current. When the mixture of sediment slows, vertical sorting occurs as the largest, most dense particles are deposited first. Turbigenic sediments often contain graded beds. |
| Unsorted sediments | A collection or deposit of fragments or particles with a wide range of sizes. |
| U-shaped valleys | Valleys that have very steep slopes and generally a flat valley floor. Valleys often formed by alpine or mountain glaciers. |
| Vertical sorting | A depositional processes that operates when a turbidity current slows down. The largest sediments are deposited first. Finer and finer sediments are deposited on top of the coarser sediments. |
| Volume | The amount of space occupied by an abject. |
| V-shaped valley | A valley formed by a river downcutting its bed. |
| Water shed | The total area drained by a river or river system. |
| Wave action | A form of erosion that results from the breaking of waves on a beach, or shoreline feature. |
| Weathering | The mechanical or chemical breakdown of rock material as a result of interactions with atmospheric conditions. |
| Wind erosion | The wearing away and/or removal of soil and/or earth materials by moving air. Wind erosion can be the cominant form of erosion in arid regions, farms, and coastal areas |
Created by:
bhowell65
Popular Earth Science sets