GEOL 104 Lecture Notes - Lecture 7: Seafloor Spreading, Lithosphere, Subsidence

• School: Queen's University
• Department: Geological Sciences and Geological Engineering
• Course: GEOL 104
• Professor: Daniel Layton- Matthews

Document Summary

Convergent boundary: oceanic-continental, oceanic-oceanic, continental-continental, used to be tropical on the edge of nepal before india collision. Highest points in the himalayas are reefs. Add water to the mantle and it nearly halves the melting point of the rocks! Oceanic-oceanic subduction form a volcanic arc and trench. No trenches at hawaii so not oo margin. Plate moves over rising mantle plume making a line of hot spot volcanoes. As it moves away volcano loses the mantle plume and its fuel. Sits there until it can melt the crust. Weakens it, rises to surface and erupts. Makes volcano: plate that created hawaii chain changed its position 48ma, seamounts sink under their weight on the crust and go below the water. Hot spots: hot spots perforate overriding plates, volcanoes build above sea level, plate motion pulls volcano off plume, volcano goes extinct and erodes, subsidence creates a guyot, hoy spots reinforce sea floor spreading, continental hot spot.