Final Chapter 4 Flashcards
What is the difference between weathering and erosion?
Weathering: the process by which rocks at the surface disintegrate or decompose
Erosion: transports rock fragments away
Which transport processes are most likely to produce sand grains that are both well-rounded and well-sorted?
(Choices: Glaciers, rivers/deltas, beach waves, wind)
beach waves and wind most effectively round sand
Are rivers more effective at rounding sand or rounding
pebbles?
rivers are more effective at rounding grains larger than 1mm, so pebbles
Are you more likely to find mica in river sediments or those deposited by wind or waves?
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Which indicates faster currents at the time of deposition: Shale, conglomerate, or sandstone?
conglomerate indicates faster currents at the time of deposition because only fast currents can effectively erode the landscape and transport large particles
How do you tell claystone from siltstone? Which formed in nearly still waters?
-siltstone feels gritty on teeth
-claystone feels smooth on teeth
-claystone was likely formed in nearly still waters
How do you tell dolostone from limestone?
the acid test, limestone will react to hydrochloric acid, dolostone is less reactive and must be in powder form to have a visible reaction
Coal indicates what type of sedimentary environment?
coal forms from the burial and compaction of vegetation that accumulated in swamps
Which sedimentary rocks form when seawater evaporates?
rock salt forms from the evaporation of seawater
Limestones form on dry land or in water? What is the name of limestone made of fossil debris? Of very tiny
grains? Of roughly spherical sand-sized grains?
-limestone can form on dry land and in water
-fossiliferous limestone is made of fossil debris
-micritic limestone forms from very tin grains
-oolitic limestone consists of sand-size spheres of calcite cemented together
What do mud-cracks suggest when you find them in ancient rocks?
mud cracks suggest the depositional environments had periodic wetting and drying
