EESA06H3 Lecture : Lecture 3
2 Feb 2011
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Document Summary
mantle movement creates - t r iple junctions 3 major fractures: middle of continent, dome forms above plume, outward flow from plume creates rifts, only one rift develops into an ocean. Failed rifts are preserved in modern continents from the breakup of pangea they just sit there and may fill up with sediments. example of failed rifts in canada: ottawa river valley and st. lawrence river valley: control river flow, generate earthquakes. continent undergoes extension, the crust is thinned and a rift valley forms. continent tears in two, continent edges are fractured and uplifted, basalt eruptions form oceanic crust. continental sediments blackout the subsiding pressure margins to keep continental shelves, the ocean widens and a mid-ocean ridge develops as in the. ocean has a mid-ocean ridge, and always widening. continental breakup and birth of a new ocean. somalian plate the horn of africa will break away and become an ocean.
