EESA06H3 Lecture Notes - Lecture 7: Oceanic Crust, Facies, Compressive Stress
Document Summary
Hotspot trails old dead volcanoes, flat tops (from erosion), below seas level, dead volcano. Hotspots majority occur on oceanic plates. Relative ages of islands: the youngest island above the hotspot, eventually go under sea level, systematic aging of the rocks as you go down the trail. Gives us a clue of plate movement. Bathymetric map that shows water depths. Geologists like this area because there is no vegetation = young landscape, still actively evolving. Barrel cactus are the pioneer/first plants grow in cracks of lava, Islands after 3 million years become completely submerged. Pyroclastic layers of ash that falls on the land that blows out underwater, think of a. Snow avalanche" that happens under water - laminated sediments. Scoria large pieces of burnt rock found around cinder cones. Trace fossil track of organism, like footprints, turtle tracks to lay eggs. Lithification to turn a sediment into rock. Compaction to squeeze water and air out of something.
