!GLG 101-Illustrated Vocabulary-Chapter 14
!Oceans, Waves, and Beaches
copyright 2003-Roger Weller
!abyssal plains
*the flat, deep part of the ocean floor, two to three miles below sea level.
!asymmetric ripple mark
*a ripple mark with a steep, short slope on the downstream side of its crest and a low
angle, long slope on the upstream side. Preserved ripple marks of this type are indicators
of current directions of ancient streams.
*[Ripple Marks-Asymmetric-1]
*[Ripple Marks-Asymmetric-2]
*[California-Ripple Marks-1]
!atoll
*a circular chain of coral islands surrounding a lagoon
!barrier island
*a long island built of sand that runs parallel to the shoreline
!beach
*a relatively flat, slightly dipping portion of the shoreline of a lake or ocean; may be
covered with sand, gravel, or rocks.
*[Oregon-Sandy Beach]
*[Oregon-Rocky Beach]
!continental shelf
*the low sloping submerged portion of the edge of a continent that ranges from the
shoreline to a depth of approximately 200 meters. Sediments deposited in this region are
usually laid down in a stable, quiet manner.
!continental slope
*the steeper slope of the submerged margin of a continent that extends from the
continental shelf to the continental rise; this region can be an active area of turbidity
flows.
!crossbedding
*a primary sedimentary structure in which one set of inclined sedimentary layers is
beveled off by an erosional process and a new set of sedimentary layers is deposited on
top of the truncated original layers; common in stream sediments and sand dunes.
*[Crossbedding-Roadcut-2]
*[Crossbedding-Roadcut-4]
!island arc
*a curved chain of volcanic islands ajacent to an oceanic trench and overlying a
subduction zone.
!longshore drift
*a current moving parallel to the shoreline that is responsible for moving sand grains
along the shoreline
!oceanic ridge
*an underwater ridge formed where two crustal plates are pulling apart. The MidAtlantic Ridge and the East Pacific Rise are two good examples.
!seafloor spreading
*occurs along the crest of oceanic ridges where the oceanic crust is being pulled apart
and lava is filling the fissures, thereby creating new seafloor.
!seismic sea wave
*this is the correct term to use in referring to large ocean waves created by earthquakes.
Earlier terms applied to these waves were tidal waves and tsunamis.
!spit
*a linear extension of land into an ocean or lake; may consist of a sandbank, shoal, or
reef.
!spreading center volcanism
*along an oceanic ridge where seafloor spreading is occurring, lava emerges where the
oceanic plates are pulling apart and opening up fissures.
!trench
*a depression on the ocean floor where oceanic crust is being subducted
!tsunami
*Japanese word for seismic sea wave
!turbidites
*sediments deposited by turbidity flows.
*[California-Anchor Bay-1]
*[California-Anchor Bay-2]
*[California-Anchor Bay-3]
*[California-Turbidites Cut by Fault]
*[California-Turbidites-1]
*[California-Turbidites-Normal Fault]
!turbidity Flow
*an underwater flow of dense turbid water; sometimes this density current is caused by
an underwater avalanche on the continental rise which was triggered by an earthquake.
!wave Action
*a mechanical weathering force capable of breaking and rounding rock fragments
through constant abrasion.
*[California-Coast-Wave Action]