Study Guide for GEOL 454 Final Exam

Study guide for GEOL 454 Final Exam

KARST Requirements for karst topography: Carbonates (limestone, dolomite) Groundwater Groundwater terms you should understand zone of aeration (vadose zone) capillary fringe water table phreatic zone cone of depression aquifer (confined and unconfined)/aquitard artesian flow Dissolution controls Permeability Porosity Bedding Joints Relief Climate (increased availability of water promotes karstification) Vegetation Karst features Springs (exsurgent vs resurgent) Travertine Dolines (sinks, sinkholes) Uvalas (coalesced dolines) Polje (even bigger than uvala) Valleys (blind, pocket, and dry) Allogenic valley Cockpit/tower topography (tropical karst) Caves Controls on cave growth, i.e., flow rate, etc

Sample question: Typically, runoff in an individual portion of a karst terrain is accomplished through a relatively large passage, as opposed to many small pathways. Explain the process by which a single passage is formed and give an example where multiple passages (i.e., mazes) might be favored.

1 EOLIAN Conditions that promote relative effectiveness of eolian processes Sparse vegetation; unconsolidated sediment; wind Resistance (vegetation, clast size, cement) vs Energy (wind direction, velocity, turbulence) Desert pavement winnowing Entrainment threshold (function of wind velocity, grain size, roughness, packing, moisture/cohesion) Suspension vs saltation vs surface creep Abrasion controlled by wind velocity and particle abundance in air column landforms Erosional abrasional: ventifacts, yardang deflational: deflation hollows, blowouts, pans Depositional ripples, dunes, draa, loess Dune types transverse, parabolic, barchan, longitudinal, star, coppice

Sample question: What climatic/physical conditions are necessary to make wind an effective agent of erosion (e.g., climate, sediment characteristics, etc)?

GLACIAL Glaciology Snow to ice metamorphosis Firn, firn line Glacial mechanics Sliding/creep Flow Surging glaciers Regelation (pressure at upstream side of obstruction melts ice, re-freezes on downstream side where pressure is reduced) Stratification of ice; foliation Crevasses (e.g., at localized acceleration, base topography variation) Zone of accumulation vs zone of ablation main processes in each zone balance controls advance or recession rate

2 Types of glaciers Cirque glaciers, valley glaciers, piedmont glaciers, ice caps, ice sheets Active vs passive glaciers Temperate glaciers vs cold or polar glaciers Glacial geomorphology Erosion Abrasion striations, grooves, crescentic marks Plucking/quarrying roche moutonee Cirques formation process, beginning with nivation Tarns, paternoster lakes Troughs, fjords Cols, arêtes, horns Nunataks Depositional (drift) Non-stratified drift till (basal, lodgement, ablation, moraine) Moraines end, terminal, recessional, lateral, medial, ground Drumlins Stratified drift (fluvio-glacial, or marine/lacustrine influence) proglacial outwash plain, valley train, sandur kame and kame terrace esker kettle hole lake Jokulhlaups (glacial outburst flood) as opposed to a moraine dam failure flood Great Ocean Conveyor Belt (inter-relation of global climate/circulation patterns and glaciation) possible explanation of Younger Dryas period

Sample question: What is meant by temperate (warm-based) and polar (cold-base) glaciers? Under what conditions would you be likely to find each? What differences would you expect in the nature of erosion, transport, and deposition done by each type of glacier?

3 PERIGLACIAL Permafrost Active layer; permafrost table; level of zero annual amplitude Talik Mean annual surface temperature and geothermal heat control depth of permafrost Surface water inhibits permafrost growth Continuous vs discontinuous vs sporadic permafrost Difficulty of construction in permafrost regions Frost action (freeze/thaw) Frost wedging Frost heaving Creep Frost push and frost pull (sorting by size) Needle ice (piprake) Frost cracking Mass movement: soliflucation and frost creep Solifluction lobes Rock glaciers (ice cored vs ice cemented) steep face; flow lobes Ice wedges/ice wedge polygons Pingos (open- and closed-system) Patterned ground sorted by grain size (usually fine in middle, coarse at edges) polygons, circles, stripes poorly understood; may be caused by convection of less dense deep material, with density differences caused by freeze-thaw processes

Sample question: How could you recognize periglacial areas on a map or air photo?

4 COASTAL Waves Orbital motion Wave refraction Shoaling Surf zone (where waves break) Waves of translation Tsunamis Storm surge Tides spring and neap tidal bores Rip currents Longshore currents Beach (littoral zone) beach profile berm beach face longshore bars and troughs Beach cusps, rhythmic topography, and capes Landforms Erosional wavecut platform marine terrace (abandoned wavecut platform) stacks, arches, caves Depositional spits and baymouth bars tombolo barrier islands tidal inlets, lagoons Engineering features Seawall; breakwater; groin; jetty Reefs Climatic indicators Fringing; barrier; atoll Key/cay

Sample question: How are marine terraces formed? What mechanisms affect their elevation with respect to sea level?

5 VOLCANIC Basalt plateaus columnar jointing Volcanic neck Tephra deposits tephrachronology Lahar: volcanic debris flow containing pyroclastic material and water (often from melting glaciers on the volcano) Nuee ardente: rapid, turbulent cloud of gas and ash; sometimes burning Jokulhlaup: glacial outburst flood; can be caused by volcanic heating of glacier

Sample question: What is tephrachronology? Describe a possible application of it.

TECTONIC Fault scarp triangular facets; sag ponds Monoclinal scarp Lineament Shutter ridges Fault block mountain Rift valley Horst/graben

Sample question: What climatic conditions favor the preservation of tectonic geomorphic features?

6 ARID, SEMIARID & SAVANNA REGIONS Causes of aridity subtropical anticyclonic belts middle latitudes – distance from ocean, rain shadow, western side of continents Savanna Semiarid Arid landforms playa reg/desert pavement dunes internal drainage piedmont, alluvial fans and bajadas, pediment Semiardi landforms steppes/prairies/pampas/veld – grass cover rivers graded externally plains or low, dissected plateaus pediments/alluvial fans Savanna landforms inselbergs – double surface of leveling

Sample question: Explain the processes operating in the two surfaces of the double surface of leveling, and how these influence the height to which inselbergs protrude above the surrounding plain.