Hotspots in the Mantle
00 deg 19.6'N
Longitude: 91 deg 41.2W
Wind Direction: S
Wind Speed: 22 Knots
Sea State 4
Swell(s) Height: 2-5 Foot
Sea Temperature: 63°F (17.2°C)
Barometric Pressure: 1013.0 MB
Visibility: 12 Nautical Miles
Eggs and potatoes
Bacon, ham and sausage
(Dried cereal is always available in the pantry)
OJ in a bucket
Quiche - 2 kinds
Chicken noodle soup
Fried pork chops
Orange Roughy fish
September 4, 2001
by Christina Reed
If we could rewind time, like a movie, we would see the Galápagos
Islands erupt in reverse and follow them back to where they
first erupted from the sea floor.
Looking at a map of the Galápagos it is impossible to tell where these
islands originated. But if we date the rocks we can see their progression through
time, with the youngest, or most recent, islands created at the western edge
of the archipelago, such as Fernandina.
western volcanoes are on the leading edge of what is called
While Earths plates move across the surface
of the globe, magma from deep within Earth rises to the surface
in certain locations, called hot spots. Upwelling of
deep mantle material brings excess heat and magma to the surface, Mark
Kurz says. Because these upwellings are stationary, relative
to the movement of oceanic plates, plate motion pushes the
volcanoes over the hotspots like a conveyor belt over a candle.
When directly over a hotspot a lot of magma is delivered to
the surface and volcanoes form. Eventually, when the volcano
is pushed far enough from the hotspot it loses its source of
magma and becomes extinct.
The best known example of ocean islands forming
over a hotspot is the Hawaiian Island chain. On the largest and
southern-most island of Hawaii, Kilauea volcano has been erupting
continuously since 1983. Tourists can walk on Kilauea lava flows
that are only days or weeks old. The Big Island of Hawaii also
has the largest volcano on earth: Mauna Loa.
But on the northern islands, such as Oahu,
the volcanoes havent erupted
for millions of years. Lush vegetation covers their volcanic terrain. The Big
Island volcanoes are presently active because they are closer to the leading
edge of the Hawaiian hotspot. The northern islands of Oahu and Kaui do not have
active volcanoes because they have moved away from the hotspot.
In the Galápagos, the youngest island, Fernandina, erupted in 1995. It
has been the most active volcano in the archipelago in historic time. As we collect
rocks from the submarine slopes of Fernandina and Isabela, we hope to better
understand the hot spot that created these Enchanted Islands.
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