ERS120H5 Lecture 4: ERS120 - Lecture 04
23 Oct 2017
School
Department
Course
Professor
Document Summary
The plate withholder-aged oceanic lithosphere will subduct when oceanic crust meets older oceanic crust. The himalaya continent-continent collision: detached oceanic lithosphere, continues to sink. The east african rift - ocean-ocean divergence: oceanic crust, dikes = vertical structure, pillow basalt = place where magma is erupting onto ocean floor, oceanic transform faults. Initial rift forms, but it isn"t straight: as rifting progress, spreading ridges from perpendicular and transform faults form parallel to the plate motion. Stable while the plate moves on through the top. E. g. sewing machine (as needle punches through fabric and moves on) In the diagram, the lettered objects represent volcanoes formed on an oceanic tectonic plate above a hotspot. The arrow indicated the direction of plate motion. How fast do plates move: north atlantic ~1. 2 cm/yr, south atlantic ~1. 5-2. 5 cm/yr, east pacific ~3. 8 cm/yr. Convection: hot, less dense water rises, water cools becomes more dense, sinks. Plate forces ridge push and slap pull.
