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Hawaiian Island Geology. Over 100 volcanoes in a volcanic island arc system. Meiji (3000 m deep). Big Island. Hawaiian Islands. Niihau. Kauai. Oahu. Molokai. Lanai. Maui. Hawaii. Bathymetric Profile of Hawaiian Emperor Chain.
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Over 100 volcanoes in a volcanic island arc system Meiji (3000 m deep) Big Island
Hawaiian Islands Niihau Kauai Oahu Molokai Lanai Maui Hawaii
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)
Movement of Hawaiian Islands Moves in a northwesterly direction Much of the Hawaiian island arc is underwater and extends toward Midway
WE’VE GOT HOT SPOTS ALL OVER THE PLACE Other examples of hot spots include: Cape Verde (off the coast of Senegal), Galapagos Islands (off the coast of Equator), Society Islands (French Polynesia), Tristan da Cunha (southern Atlantic), Yellowstone, Ethiopia Plateau, Lord How (near Sydney), Iceland, and many more.
Movement away from hotspot Older islands erode and subside
Aging islands and coral: • Drilling and removing core sample • C14 dating
Darwin’s 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
Fringing Reef Shoreline Reef Flat Reef Front
Kaneohe Bay Barrier Reef Patch Reef Fringing Reef
Reef Flat of a barrier reef Lagoon Reef Flat of a Barrier Reef Coral Island (Cay or Motu) Reef Flat Reef Front Open Ocean
Belize- Blue Hole Atoll
Midway Atoll Kure Atoll (28° 25' N - 178° 20' W) Pearl & Hermes Atoll