GEO 121 10th EditionFinal Exam Study Guide Lectures: 34 - 39Lecture 34 (April 29)A. Forms of Mass Wastingi. Creep- slow downslope movement of Earth material involving the lifting and falling action of sediment particlesii. Earthflow- iii. Landslide- Layperson's term for any fast mass wasting; used by some earth scientists fir massive slides that involve a variety of earth materialsiv. Slump- Thick unit of unconsolidated fine-grained material sliding downslope on a concave, curved slip planei. Streamsi. Perennial- Describes streams that conduct flow continuously all year ii. Intermittent- Describes streams that conduct flow seasonallyii. Stream Patternsi. Dendritic- A term used to describe a drainage patterns that is treelike with tributaries joining the main stream at acute angles ii. Trellis- Develops in folded topography like that found in the Appalachian Mountains of North America. Down-turned folds called synclines form valleys in which resides the main channel of the stream. Short tributary streams enter the main channel at sharp angles as they run down sides of parallel ridges called anticlines. Tributaries join the main stream at nearly right anglesiii. Radial- develops around a central elevated point. This pattern is common to such conically shaped features as volcanoes. The tributary streams extend the head-ward reaches upslope toward the top of the volcano ii. Cycle of Erosioni. Young - In this stage the river flows along an uneven surface and there is intensive bottom erosion, the gradients are steep and the erosion is rapid. The rapid deepening of the channel leads to the formation of V-shaped valleys.ii. Mature- In this stage rivers flow with a graded profile i.e. it attains a profile of equilibrium. The land mass is fully dissected and a well-integrated drainage system is developed. Ridges and valleys develop prominently. Flood plains develop and river meandering takes place. The topography consists of features such as: hogbacks, cuestas, mesa, butte, meanders, oxbow lakes, natural bridge, flood plains, alluvial fans etc.iii. Old Age- In this stage the gradients are gentle and the velocity is low. Accordingly the river lose most of its erosive power and flow in a sluggish manner. In old age a river has maximum meandering. The river at this age does little of erosion and transportation but is mostly engaged in deposition. This stage is characterized by the development of distributaries and the river flows almost at the base level of erosion. The topography consists of features like peneplains, natural levees, deltas etc.iv. Additional Notes- Most of the cycles of erosion do not reach the final stage, as sometime during their operation either climatic or tectonic disturbances take place, and thus results in an incomplete or partial cycle.Lecture 35 (May 1) A. Fluvial Processesa. Erosion- Removal of Earth materials from a site by gravity, water, wind, or glacial iceb. Transportation- Movement of Earth materials from one site to another by gravity, wind, water, or glacial icec. Deposition- Accumulation of Earth materials at a new site after being moved by gravity, water, wind, or glacial ice B. Fluvial Landformsa. Back Swamps- In geology backswamp is the section of a floodplain where deposits of fine silts and clays settle after a flood. Backswamps usually lie behind a stream's natural leveesb. Flood Plains- A low gradient area adjacent to many stream channels that is subject to flooding and primarily composed of alluvium c. Valley- An elongated lowland between ranges of mountains, hills, or other uplands, often having a river or stream running along the bottom.d. Bluff- A bluff is a steep cliff, or wall of rock or soil. Most bluffs border a river or its flood plain.Bluffs may form along a river where it meanders, or curves from side to side. Water on the outside of the curve flows faster. This erodes, or wears away, the lower part of a river bank. No longer supported, the upper part of the bank breaks off, leaving a high, steep walle. Meander- A broad, sweeping bend in a river or streamf. Meander Scars- A meander scar, occasionally meander scarp, is a geological feature formed by the remnants of a meandering water channel. They are characterized by "a crescentic cut in a bluff or valley wall, produced by...a meandering stream." They are often formed during the creation of oxbow lakesg. Ox-bows- Lakes or ponds that are found in the meander cut-off on a flood plainh. Cut Bank- The steep slope found on the outside of a bend in a meandering stream channeli. Point Bar Deposits- Deposit of alluvium found on the inside of a bend in a meandering stream channelj. Natural Levees- A bank of a stream channel (or margin of mass wasting flow channel) raised by deposition from flood (or flow) deposits; artificial levees are sometimes built along stream banks for flood controlLecture 36 (May 4)A. Ground Watera. Infiltration- The process of water seeping downward into the soil or other surface materialsb. Percolation- Subsurface water moving downward into the lower zones by the pull of gravityc. Zone of Saturation- Subsurface water zone n which all voids in rock and soil are always filled with water; the top of this zone is the water tabled. Water Table- Upper limit of the zone of saturation below which all pore spaces are filled withwatere. Aquifer- A rock layer that is a container and transmitter of groundwater; it is both porous and permeablef. Cone of Depression- A cone of depression occurs in an aquifer when groundwater is pumpedfrom a well. In an unconfined aquifer (water table), this is an actual depression of the waterlevels. In confined aquifers (artesian), the cone of depression is a reduction in the pressure head surrounding the pumped wellB. Ground Water Related Landforms (Karst)a. Caves- Also called a cavern, a natural void in rock created by solution that is large enough forpeople tom enterb. Sinking Streams- Any stream that disappears underground, typically into a swallow hole.c. Sinkholes- Also called a dot-line, a roughly circular service depression related to the solution of rock in Karst areasd. Karst- Unique landforms and landscapes derived by the solution of soluble rocks, particularlylimestoneB. Glacial Processesa. Snow- Precipitation in the form of ice crystalsb. Firn- Compact, granular snow formed by partial melting and refreezing due to overlying layers of snowc. Glacier- A large mass of ice that flows as a plastic solidLecture 37 (May 6)A. Agesa.