Exogenic processes Flashcards
How is the temperature of water vapor distributed throughout the atmosphere?
Troposphere = fall in ° of water vapor
Stratosphere = rise in ° of water vapor
Mesosphere = fall in ° of water vapor
Thermosphere = rise in ° of water vapor
What is orographic precipitation?
Water evaporates from warm ocean –> rises over land –> falls on mountainside –> rain shadow (no rain, arid) on leeward side of the mountain
How are storms created?
By warm winds filled with water
More time for erosion than deposition (more energy at erosion-time)
What are tempestites?
= individual storm deposits deposited by single storm events
Idealised tempestite bed = sharp, possibly erosive base, overlain by structureless coarse sediment (coarse sand and/or gravel)
Storm wanes –> hummocky–swaley cross-stratification forms in finer sands –> overlain by fine sand and silt that shows horizontal and wave-ripple lamination –> at the top of the bed the sediment grades into mud
What is HCS and SCS?
Product of strong and complex wave activity, mainly in areas below fair-weather wave base.
Typically interpreted as produced by !storm activity!
Typically found in silt or fine sandstones
HCS = hummocky cross-stratification
SCS = swaley cross-stratification
What is the Barycenter?
The spot/axis that the Earth rotates around
How does the tides work?
Gravity: Acceleration (force) exerted by any body on another
Counterbalanced by centrifugal acceleration
What create the tidal force is the difference between the two!
What is important to know about the tides?
Ocean tides are measured in vertical direction (rise/fall) - but a cause of currents, a horizontal flow
Tides do NOT result from water being pulled towards the Sun or the Moon. Tides are a horizontal phenomenon!
What are the three tidal regimes?
Microtidal: tidal range < 2m
Mesotidal: 2m < tidal range < 4m
Macrotidal: tidal range > 4m
What is stronger on the Earth, the tidal force from the moon or the tidal force from the Sun?
Tidal force from the Moon
Despite the size of the Sun, the Moon is much closer = 2.2x greater tidal effect on the Earth
What is spring tide and neap tide?
Spring tide = when the Moon is aligned with the Sun
Neap tide = when the Moon is perpendicular to the Sun
What are the two types of tidal deposits?
1 up close that alternates between clay and sand
1 farther away that alternates between mostly clay and mostly sand (spring (sand dominated) and neap (clay dominated) cycles) –> ergo the up close-type but many of them
What is sigmoidal cross-bedding?
Cross-bedding with three darker ‘areas of lines’ (mud deposits only) during a lunar cycle (the rest are lighter areas of lines (mixed sand and mud))
Which laminations are associated with tidally-influenced environments?
Flaser, wavy and lenticular lamination
Rhythmic variation of mud-to- sand ratio.
