VUME Upper Mantle of the Earth

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Ophiolite Pulses.





Ophiolite Pulses Furthermore, the occurrence of ophiolites throughout Earth history is not constant but rather they were formed and emplaced at specific intervals. Reported formation ages of ophiolites show three distinct peaks at about 750, 450 and 150 Ma, respectively. These are called ophiolite pulses. Each pulse corresponds to the period of worldwide magmatic event as represented by voluminous granite intrusions.
These intervals correspond closely to times of super-continent break-up and dispersal—not because they form at the ridges that separate the drifting continents, but because the large ocean basin that must coexist with any super-continent must subduct along new subduction zones as rifting progresses.
Ophiolite pulses coincide with the timing of major collisional events during the assembly of supercontinents (i.e. Rodinia, Gondwana and Pangaea), dismantling of these supercontinents, and increased mantle plume activities that formed widespread large igneous provinces (LIPs).