Describe the mechanism that controls the formation of the Hawai'ian Islands. Is this island chain still actively forming?
The Hawai'ian Islands were formed as a result of a hot spot, the surface expression of a stationary mantle plume. As the Pacific Plate moves in a westerly- northwesterly direction over the hot spot, the high temperatures and rising magma from the plume weaken the crust and form a volcano on the ocean floor. The volcano eventually grows large enough to break the surface of the ocean, becoming a volcanic island. Because the Pacific Plate is moving, the volcanic island eventually is carried away from the source of origin, and a new island forms over the stationary hot spot. Over millions of years, a volcanic island chain is formed. The Emperor Seamounts north of Hawai'i are the oldest remnants of this island chain, and the island of Hawai'i is the youngest. A new island, Loihi, is currently being formed on the ocean floor and will become the next Hawai'ian island in about 30,000 years.
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The breakup of Yugoslavia during the 1990s was caused mainly by
A) ethnic cleansing. B) the assassination in Sarajevo of the heir to the throne of Austria-Hungary. C) rivalries among ethnicities. D) NATO. E) espionage by Russian agents.
What is the cultural origin of the majority of Australia's population?
A) South Asia (India, Pakistan) B) United States C) East Asia (China, Japan, Korea) D) British Isles (England, Scotland, Ireland) E) Aboriginal
The diversity pattern of reef-building coral observed in today's oceans is related to which of the following?
A) Increased nutrients provided by upwelling B) The distance from Earth to the Sun C) The El Nino Southern Oscillation D) The mass extinction that killed the dinosaurs E) The past positions of the continents
During the early Paleozoic, sea levels were higher than they are today
a. True b. False