Hawaiian Island Geology

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Hawaiian Island Geology
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Over 100 volcanoes in a volcanic island arc
system
Meiji (3000 m deep)
Big Island
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Hawaiian Islands
Niihau
Kauai
Oahu
Molokai
Lanai
Maui
Hawaii
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Bathymetric Profile of Hawaiian Emperor Chain
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J. Tuzo Wilson (1963), a Canadian geophysicist
,came up the "hotspot" theory.
volcanoes of the Hawaiian chain should get
progressively older and become more eroded the
farther they travel beyond the hotspot.
Pacific Plate
Kauai (oldest)
Oahu
Maui
Hawaii (youngest)
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Movement of Hawaiian Islands
Moves in a northwesterly direction
Much of the Hawaiian island arc is underwater
and extends toward Midway
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Movement away from hotspot
Older islands erode and subside
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• Aging islands and coral
• Drilling and removing core sample
• C14 dating

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Darwins Theory of Coral Atoll Formation
Subsidence Theory
Fringing Reef- boarders coastline closely
Island subsides
Barrier Reef- separated from
land by a lagoon
Atoll- coral ring with central lagoon
lagoon is a shallow area with a sandy floor,
patch reefs, and patches of seagrass
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Fringing Reef- Tahiti
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Fringing Reef
Shoreline
Reef Flat
Reef Front
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Barrier Reef Profile
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Australia- Great Barrier Reef
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Kaneohe Bay
Barrier Reef
Patch Reef
Fringing Reef
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Reef Flat of a barrier reef
Lagoon
Reef Flat of a Barrier Reef
Coral Island (Cay or Motu)
Reef Flat
Reef Front
Open Ocean
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Cross Section of an Atoll
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Belize- Blue Hole
Atoll
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Midway Atoll
Kure Atoll (28 25' N - 178 20' W)
Pearl Hermes Atoll
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Inquiry

• The oldest seamount in the Hawaiian Emperor Chain
  is _____?
• What direction are our islands moving?
• What seamount will be the newest Hawaiian Island?
• Key features of a barrier reef are_____?
• When an atoll subsides it often forms a _____?