EESA06H3 Lecture Notes - Extrusive Rock, Viscosity, Silt
15 Apr 2013
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Document Summary
Islands are the tip of an iceburg of a submerged plateau. Right at the head of the island group. They then erode (dead volcanoes) and have flat tops below sea level. They become guyotx: a flat topped dead volcano as part of a hot spot trail. About 40 hotspots mostly in oceanic plates. In terms of the islands age two things were found: The youngest island down the trail you have extinct volcanoes eventually going below sea level, systematic ageing of the rocks as you move away from the hotspots. Orientation of the hotspot = gibes the direction of plate movement. Hotspots play a key role in plate tectonic theory. Bathymetric a map that shows water dense. Bumps as a result of magma hitting water (phreato(water) magmatic erruptions) You can tell it is a young landscape because there is no vegetation or plants. Image: eroded remnant of and old volcano (dark rock daggaring upward) actively collapsing.
