Editing Supercontinent (section)

==Volcanism==
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<!-- Deleted image removed: [[File:FigureSupercontinentBreakup.jpg|thumb|The effects of mantle plumes possibly caused by slab avalanches elsewhere in the lower mantle on the breakup and assembly of supercontinents<ref name=rogers />]] -->

The causes of supercontinent assembly and dispersal are thought to be driven by [[convection]] processes in [[Earth's mantle]]. Approximately 660&nbsp;km into the mantle, a discontinuity occurs, affecting the [[Earth's crust|surface crust]] through processes involving [[mantle plume|plumes]] and ''superplumes'' (aka [[large low-shear-velocity provinces]]). When a slab of the [[Subduction|subducted]] crust is denser than the surrounding mantle, it sinks to discontinuity. Once the slabs build up, they will sink through to the [[lower mantle]] in what is known as a "slab avalanche". This displacement at the discontinuity will cause the lower mantle to compensate and rise elsewhere. The rising mantle can form a plume or superplume.<ref name=rogers />

Besides having compositional effects on the [[upper mantle]] by replenishing the [[incompatible element|large-ion lithophile elements]], volcanism affects plate movement.<ref name=rogers /> The plates will be moved towards a geoidal low perhaps where the slab avalanche occurred and pushed away from the geoidal high that can be caused by the plumes or superplumes. This causes the continents to push together to form supercontinents and was evidently the process that operated to cause the early continental crust to aggregate into Protopangea.<ref name='piper3'>Piper, J.D.A. "Protopangea: palaeomagnetic definition of Earth's oldest (Mid-Archaean-Paleoproterozoic) supercontinent." Journal of Geodynamics. 50 (2010): 154–165.</ref> 

Dispersal of supercontinents is caused by the accumulation of heat underneath the crust due to the rising of very large [[convection cell]]s or plumes, and a massive heat release resulted in the final break-up of Paleopangea.<ref name="piper4">Piper, J.D.A., "Paleopangea in Meso-Neoproterozoic times: the paleomagnetic evidence and implications to continental integrity, supercontinent from and Eocambrian break-up." Journal of Geodynamics. 50 (2010): 191–223.</ref> Accretion occurs over geoidal lows that can be caused by avalanche slabs or the downgoing limbs of convection cells. Evidence of the accretion and dispersion of supercontinents is seen in the geological rock record.

The influence of known volcanic eruptions does not compare to that of [[flood basalt]]s. The timing of flood basalts has corresponded with a large-scale continental break-up. However, due to a lack of data on the time required to produce flood basalts, the climatic impact is difficult to quantify. The timing of a single lava flow is also undetermined. These are important factors on how flood basalts influenced [[paleoclimatology|paleoclimate]].<ref name=flutaeu />