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	GEOLOGY INDEX	STUDY QUESTIONS

Interactions between the asthenosphere and the lithosphere create most of the major features at the surface of the earth. Upwelling and convection cells in asthenosphere cause the lithosphere to break into pieces called plates, that move, and, in turn, interact mostly at their boundaries.  This creates distinctive sets of features with each boundary type.

I.  PLATE BOUNDARIES (3 major types of boundaries between plates)
Type of Boundary	Associated Features	Where can you see this?
A. DIVERGENT either on cont or ocean	Ridge systems Rift Vulcanism- ranges from isolated volcanos to basalt plateaus Shallow focus Earthquakes***	E. Africa Rift Valley Red Sea Mid Ocean Ridges in all oceans
B. CONVERGENT 1. Ocean/ Ocean Convergence	Oceanic lithoshere subducted Subduction Zone Accretionary wedge (=prism) Vulcanism on up plate-Vulcanic Island arc w/ associated trench Trench Shallow, Intermediate and Deep focus Earthquakes	Aleutians Islands Phillipines Islands Mariannas Islands Windward Islands of Carribean
2. Ocean/Continent Convergence	Oceanic litho subducted Subduction Zone Accretionary wedge (=prism) Vulcanism on up (=cont.) plate Marginal Mountains on up plate (=cont) Trench Shallow, Intermediate and Deep focus Earthquakes	Andes Alaska Peninsula SE Asia: Java, Sumatra , etc
3. Continent/Continent Convergence	Neither plate subducted  Internal Mountains Underplating Shallow and Intermediate focus Earthquakes (No vulcanism)	Himalayas Urals Appalachians
C. TRANSFORM	Transform Faults Shallow focus Earthquakes	California Central America
II. INTRA-PLATE  ACTIVITY  (activity within a plate)
	Hot Spots. Primary indicator is vulcanism.  Vulcanic Island arcs  w/o associated trenches or basaltic plateaus.	Yellowstone Iceland Hawaiian Islands and Emperor Sea Mounts
	Transform Faults	Asian Continent Across ridges in oceanic plates

***Shallow focus earthquakes originate between the surface and ~60 mi.down, intermediate focus earthquakes between ~60 and 175 mi. in depth, and deep focus earthquakes, deeper than 175 mi.