Shared Flashcard Set

Details

Geology exam 3
Mass Movement, Running Water, Oceans and Coasts, Glaciers and Deserts
164
Geology
Undergraduate 3
11/28/2012

Additional Geology Flashcards

 


 

Cards

Term

 

 

 

 

Mass Movement

Definition
  • Also known as mass wasting
  • gravitationally caused downslope transport of rock, regolith (soil, sediment, and debris), snow, and ice
  • initial step in sediment transportation
  • significant agent of landscape change

 

Term

 

 

 

 

Creep

Definition
  • refers to the slow, grdual downslope movement of regolith on a slope
  • commonly, creep affects soil
  • referred to as "soil creep"
  • due to expansion and contraction
  • grains are moved perpendicular to slope upon expansion and vertically by gravity upon contraction
Term

 

 

 

 

Solifluction

 

 

 

 

 

 

 

 

 

 

Definition
  • slow downhill movement of tundra
  • generates hillsides with solifluction lobes
  • type of creep in treeless tundra regions
Term

 

 

 

 

Slumping

Definition
  • sliding of regolith as coherent blocks
  • slippage occurs along spoon shaped "failure surface"-surface on which slimp slips
  • head scarp: distinct, curving step at the upslope edge of a slump, where the regoith detaches
  • bulging toe: end of slump where the ground elevation rises as the slump rides up and over preexisting land surface
Term

 

 

 

 

Mudflow

Definition
  • a slurry of water and fine sediment
  • speed of mudflow depends on the slope angle and the water content
Term

 

 

 

 

Debris Flow

Definition
  • a mudflow with many large rocks as well as water and fine sediment
  • speed of debris flow depends on the slope angle and the water content
Term

 

 

 

 

Lahars

Definition
  • a volcanic mud or debris flow
  • contains volcanic ash mixed with water
  • water is from heavy rains or melted glacial ice
Term

 

 

 

 

Rock slide (type of landslide)

Definition
  • movement down a non-vertical slope consisting of rock only
Term
Streams
Definition
Ribbons of water that flow down channels or troughs
Term
Runoff
Definition
Water in motion over the land surface, important geologic agent
Term
Headward Erosion
Definition
Rapid erosion lengthens the channel up slope
Term
Dendritic Drainage Pattern
Definition
Branching, "treelike" due to uniform material
Term
Radial Drainage Pattern
Definition
Form a point uplift (mesa, volcano, etc.)
Term
Rectangular Drainage Pattern
Definition
Controlled by jointed rocks, vertical joints that create right angles
Term
Trellis Drainage Pattern
Definition
Alternating resistant and weak rocks, occurs in parallel valleys and ridges
Term
Watersheds (Catchments)
Definition
Land areas that drain into a specific trunk stream, collects water from a broad region
Term
Divides
Definition
Uplands that separate drainage basins
Term
Permanent Stream
Definition
Water flows all year, at or below the water table, humid or temperate climates, sufficient rainfall, lower evaporation, seasonal discharge variation, discharge increases in a downstream direction
Term
Ephemeral Stream
Definition
Do not flow all year, above the water table, dry climates, low rainfall, high evaporation, flow mostly during rare flash floods, discharge decreases in a downstream direction
Term
Dry Bed
Definition
Dry wash or arroyo or wadi
Term
Discharge
Definition
The amount of water flowing in a channel, the volume of water passing a point per unit time
Term
Scouring
Definition
Running water picks up sediment and moves it
Term
Abrasion
Definition
Sediment grains in flow "sandblast" rocks
Term
Dissolution
Definition
Mineral matter dissolves in water
Term
Sediment Load
Definition
The material moved by streams, the total volume of sediment carried by a stream
Term
Dissolved Load
Definition
Ions from mineral weathering
Term
Suspended Load
Definition
Fine particles in the flow without settling to the floor of the channel
Term
Bed Load
Definition
Larger particles roll, slide and bounce along including sand, pebbles or cobbles
Term
Alluvium
Definition
Fluvial sediments transported by a stream
Term
Base Level
Definition
The lowest point to which a stream can erode, defined by position of sea level, streams cannot erode below sea level
Term
Canyon
Definition
Steep trough sidewalls form cliffs, form in hard rocks
Term
Valley
Definition
Gently sloping trough sidewalls define a V-shape
Term
Terrace
Definition
Mark former floodplains, a step like landform
Term
Braided Streams
Definition
Streams intertwine, form where channels are choked by sediment
Term
Alluvial Fan
Definition
A gently sloping apron of sediment which accumulates from water slowing and abruptly dropping the sedimentary load
Term
Thalweg Position
Definition
Deepest channel, marks the natural direction of a watercourse
Term
Point Bar
Definition
Wedge shaped deposit where sediment accumulates
Term
Incised Meanders
Definition
High velocity meander flow
Term
Oxbow Lake
Definition
Due to high velocity flow, the meander cut-off forms this
Term
Deltas
Definition
Forms when a stream enters standing water, stream divides into a fan of small distributaries, shape due to the interplay of flow, waves, and tides, New Orleans is an example
Term
Avulsion
Definition
River overflows a natural levee upstream and begins to flow in a new direction
Term
Stream rejuvenation
Definition
Process of renewed downcutting by a stream, initiated by base level drop
Term
Stream Piracy
Definition
A stream captures another flow, captured stream flows into the new stream
Term
Superposed Streams
Definition
A stream that forms over horizontal beds that overly folded and faulted rock with varying resistance, stream maintains the geometry developed at an earlier time
Term
Antecedent Streams
Definition
Streams which existed before the mountain range uplifted, range's growth can alter the stream's course, will maintain course before uplift of range and cut directly across the range
Term
Continental Shelf
Definition
Shallow (0 to 500m), gently sloping (.3 degrees), underlain by thinning sialic crust
Term
Continental Slope
Definition
Descends from 500 m to 4 km at approximately 2 degrees
Term
Continental Rise
Definition
Transition Zone from 4 to 4.5 km
Term
Abyssal Plain
Definition
Flat, low relief bottom below 4.5 km, underlain by mafic oceanic crust
Term
Passive Continental Margin
Definition
Located far from a tectonic plate boundary, develops a broad shelf of sediment overlying sialic crust
Term
Active Continental Margin
Definition
Immediately adjacent to a tectonic plate boundary, characterized by a thin, narrow continental shelf
Term
Submarine Canyons
Definition
Relatively narrow and deep valleys, crosscut continental shelves, associated with large rivers, results from flow of turbidity currents and avalanches of sediment mixed with water
Term
Bathymetry
Definition
The form and topography of the ocean floor
Term
Seamounts
Definition
Remnants of hot spot volcanoes that are inactive act as a surface for presently active hot spot volcanoes, the Galapagos or the Hawaiian Islands
Term
Normal Marine Salinity
Definition
3.5%, reflects dissolved ions which are derived from chemical weathering of rocks
Term
Higher Salinity
Definition
Occurs due to evaporation and formation of sea ice
Term
Lower Salinity
Definition
Occurs from rainfall, glacial melt, and river input
Term
Downwelling
Definition
Surface waters are drawn upward, onshore water piles up along coast
Term
Upwelling
Definition
Deep waters are pushed upward, occurs offshore
Term
Colder or Salty Water
Definition
Denser water
Term
Warmer or Less Salty
Definition
Less dense water
Term
Tidal Reach
Definition
The range between high and low tides
Term
Intertidal Zone
Definition
Lies between tides
Term
Tides
Definition
Caused by gravitational pull of the moon and the sun, centrifugal forces from the rotation of the earth, moon and sun, orbiting moon creates the strongest tidal effects
Term
Crest
Definition
Top of a wave
Term
Trough
Definition
Low between crests
Term
Wavelength
Definition
Distance between wave crests
Term
Breakers
Definition
Waves that crash onto the beach
Term
Wave Refraction
Definition
Waves bend as they approach the shore, wave energy focuses on headlands and is weaker in embayments
Term
Longshore Currents
Definition
Flows parallel to the shore, oblique waves push sediment sideways up the beach
Term
Rip Currents
Definition
Develop when wave attack is straight on, develops perpendicular to the beach, dissipate away from the surf zone
Term
Summer Beaches
Definition
Broad, sandy beach
Term
Winter Beaches
Definition
Narrow, gravel beach
Term
Beach Face
Definition
Steep, concave zone formed by wave smash
Term
Backshore
Definition
Upper part of the beach, beyond the reach of normal high tides, often exhibit berms
Term
Barrier Islands
Definition
Elongate, linear sandbars, create a lagoon
Term
Tidal Flats
Definition
Form in intertidal zones lacking strong waves, common behind barrier islands or in estuaries, contain laminated sand and mud, confined ancient fossils found
Term
Temperate Climate
Definition
Vegetated by trees, grasses or mosses
Term
Tropical Climate
Definition
Mangrove dominated
Term
Coral Reefs
Definition
Grow in tropical marine settings, create large structures of cemented skeletons, rapid response to sea level change, hypersaline, form lagoons, precipitate salts, modify sediment accumulation, alter wave and current energy
Term
Coral Atolls
Definition
Reefs formed on subsiding volcanoes
Term
Estuaries
Definition
River valleys filled by marine water, characterized by mixing fresh and salt water known as brackish water, Chesapeake Bay
Term
Fjords
Definition
Flooded U-shaped valleys carved by glaciers, Ex. Norway, British Columbia, and New Zealand
Term
Emergent Coasts
Definition
Experience relative sea-level fall, uplift due to tectonic processes, eustatic sea-level drop, river incision, cliffs, wave-cut notches, and platforms
Term
Submergent Coasts
Definition
Experience relative sea-level rise, subsidence of a passive margin, eustatic sea-level rise, flooded river or glacial valleys create estuaries and fjords
Term
Accretionary Coasts
Definition
Net sediment accumulation
Term
Erosional Coasts
Definition
Sediment removed faster than supplied
Term
Erratics
Definition
Large boulders that are displaced geologically
Term
The Theory of Glaciation
Definition
Louis Agassiz, glaciers could explain erratics, ice age froze Europe and North America
Term
Cirque Glaciers
Definition
Fill mountain-top bowls, snow falls off steep part of mountain and accumulates
Term
Valley Glaciers
Definition
Flow like rivers down valleys
Term
Mountain Ice Caps
Definition
Cover peaks and ridges
Term
Piedmont Glaciers
Definition
Spread out at the end of a valley
Term
Continental Glaciers
Definition
Vast ice sheets covering large land areas, ice flows outward from thickest part of sheet, two remain: Greenland and Antarctica
Term
Temperate Glaciers
Definition
Ice is at or near melting temperature, flows rapidly and moves well
Term
Polar Glaciers
Definition
Ice is well below melting temperature, doesn't flow
Term
Wet-Bottom Glaciers
Definition
Water flows along base of glacier
Term
Basal Sliding
Definition
Ice slips over a meltwater/sediment slurry
Term
Dry-Bottom Glaciers
Definition
Cold base is frozen to substrate, movement is by internal plastic deformation of ice
Term
Brittle Movement
Definition
Uppermost 60 meters, tensions initiates cracking of the ice, crevasses may open and close with movement
Term
Plastic Movement
Definition
Lower than 60 meters, ductile flow occurs in deeper ice, ice flow heals cracks
Term
Zone of Accumulation
Definition
Area of net snow addition, colder temperatures prevent melting, snow remains across the summer months
Term
Zone of Ablation
Definition
Area of net ice loss
Term
Toe
Definition
The leading edge of a glacier
Term
Toe Position

Accumulation=Ablation
Definition
Glacial toe always stays in the same place
Term
Toe Position

Accumulation>ablation
Definition
The glacial toe advances
Term
Toe Position Accumulation
Definition
The glacial toe retreats
Term
Tidewater Glaciers
Definition
Valley glaciers entering the sea
Term
Ice Shelves
Definition
Continental glaciers entering the sea
Term
Sea Ice
Definition
Non-glacial ice formed of frozen seawater
Term
Icebergs
Definition
Ice debris calves off the edge off of marine glaciers
Term
Glacial incorporation
Definition
Rock is surrounded and carried off by glacial erosion
Term
Plucking
Definition
Ice breaks off and removes bedrock fragments
Term
Glacial Abrasion
Definition
A "sandpaper" effect on substrate, polishes bedrock, large rocks dragged across bedrock gouge striations
Term
Cirques
Definition
Bowl shaped basin high on a mountain, form at the uppermost portion of a glacial valley, after ice melts often filled with a tarn lake
Term
Arete
Definition
A "knife edge" ridge, formed by two cirques that eroded toward one another
Term
Horn
Definition
A pointed mountain peak, formed by three or more cirques that coalesce
Term
U-shaped Valleys
Definition
Glacial erosion creates a distinctive trough, different than v-shaped fluvial valleys
Term
Hanging Valleys
Definition
The intersection of a tributary glacier with a trunk glacier, a waterfall results
Term
Fjords
Definition
U-shaped glacial troughs flooded by the sea
Term
"Boulder Clay"
Definition
Refers to every kind of unsorted grain sizes
Term
Glacial Till
Definition
Sediment dropped by glacial ice, consists of all grain sizes
Term
Calving Icebergs
Definition
Glaciers that reach the sea
Term
Glacial Outwash
Definition
Sediment transported in meltwater, mud removed, sizes are stratified, grains are rounded
Term
Loess
Definition
Wind transported silt, tend to accumulate in downwind movement
Term
Moraines
Definition
Unsorted debris dumped by a glacier
Term
Lateral Moraine
Definition
Forms along the flank of a valley glacier
Term
Medial Moraine
Definition
Mid-ice moraine from merging lateral moraines
Term
End Moraine
Definition
Form at the stable toe of a glacier
Term
Terminal Moraine
Definition
Form at the farthest edge of flow
Term
Recessional Moraine
Definition
Form as retreating ice stalls
Term
Drumlins
Definition
Long, aligned hills of molded lodgement till, asymmetric form, common as swarms aligned parallel to ice flow direction
Term
Eskers
Definition
Long, sinuous ridges of sand and gravel, form as meltwater channels within or below ice, channel sediment released when ice melts
Term
Periglacial Environments
Definition
Characterized by year round frozen ground (permafrost)
Term
Hot Deserts
Definition
Low latitudes, low elevations, far from oceans
Term
Cold Deserts
Definition
High Latitudes, high elevations, near cold ocean currents
Term
Subtropical Deserts
Definition
Largest amount found on earth, equator, subtropics 20-30 degrees N. to S., Sahara, Arabian, Kalahari
Term
Rainshadow Deserts
Definition
Moist ocean winds are driven over mounts, dry area on the backside of back side of a mountainous region
Term
Coastal Deserts
Definition
Cool air over cold ocean water holds little moisture, air absorbs moisture when interacting with land, Atacama (Peru) Desert, lots of fog with little rainfall
Term
Interior Deserts
Definition
Air loses moisture as it crosses continents, land far from ocean can be arid, Gobi Desert in Mongolia
Term
Polar Deserts
Definition
Above 66 degrees N. and S. there is little moisture, air circulation carries dry air to polar regions
Term
Desert Varnish
Definition
Dark surface coating of iron and manganese oxides, forms very slowly by bacterial activity, dust, and water
Term
Desert Soils
Definition
Thin, with poorly defined horizons, usually colored by bedrock nearby and trace elements
Term
Surface Load
Definition
Grains moved in contact with land surface, coarser sand sized particles
Term
Saltation
Definition
Sand skipped and bounced by grain impact
Term
Suspended Load
Definition
Sediment carried in the air, finger grained silt sized "dust"
Term
Desert Pavement
Definition
A surface layer of stones, resistant to erosion, often coated with desert varnish
Term
Ventifacts
Definition
Rocks that have been abraded, pitted, etched, grooved, or polished by wind-driven sand or ice crystals
Term
Yardangs
Definition
A streamlined hill carved from bedrock or any consolidated or semi consolidated material by the dual action of wind abrasion, dust and sand, and deflation
Term
Deflation
Definition
Lowering the land surface via erosion
Term
Playas
Definition
Desert lakes that have no outlet streams, internal drainage collects water from flash floods, dissolved solids crystallize out as water evaporates
Term
Cuesta
Definition
Steep joint controlled cliff, less steep dip slope
Term
Hogback
Definition
Steeply dipping beds create a symmetric ridge
Term
Inselberg
Definition
Eroded remnant of almost complete cliff retreat
Term
Stony Plains
Definition
Sloping, gravelly alluvial plains, large boulder accumulation on plains
Term
Pediments
Definition
Ramp-like surfaces that slope up toward a mountain front, bed rock sticking up
Term
Dunes
Definition
Windblown accumulations of sand, generate enormous cross beds
Term
Barchan Dune
Definition
Stead 1 direction, scare sand
Term
Star Dune
Definition
Steady changing direction, scare sand
Term
Transverse Dune
Definition
Steady, moderate 1 direction, plentiful sand
Term
Parabolic Dune
Definition
Steady, strong 1 direction, plentiful sand
Term
Longitudinal Dune
Definition
Steady, strong 1 direction, abundant sand
Term
Ergs
Definition
Gigantic oceans of sands which develop in some deserts, Arabian Peninsula and Namibia, existed in the past in Permian and Jurassic Periods
Term
Desertification
Definition
Aridification of non-desert areas, overpopulation, overgrazing, careless agriculture, diversion of water supplies, leads to famine
Supporting users have an ad free experience!