Ongoing 2005).An example in Sierra Nevada, Pliocene magmatism

Ongoing and ancient removal events may be traced through anomalous surface observations, including the generation of orogens, crustal contraction and extension, increased heat flow and magmatism. However, there may be no associated magmatism in some intracratonic basins that appear to be linked with lithosphere removal, (Elkins-Tanton, 2005).An example in Sierra Nevada, Pliocene magmatism was accompanied by significant vertical deflection at surface, with Pliocene uplift at the eastern side and Pliocene-Quaternary subsidence at the western side. The temporal variations in surface uplift and subsidence suggest that lithosphere detachment migrated westward across the Sierra Nevada. This indicates that magmatism migrates with the delamination hinge as shown in delamination model 2 above, (Saleeby et al. 2013)This is further proven by the Quaternary volcanism in this region which mainly occurs in the area with Pliocene surface uplift, while the region that has the most recent rock uplift also exhibits increasing surface heat flow. Seismic studies show an eastward dipping high velocity anomaly beneath this region. The high-velocity anomaly is interpreted to be the mantle lithosphere and its geometry is consistent with lithosphere delamination, (Saleeby et al. 2013).Below the Tulare Basin in Western Sierra Nevada, the mantle lithosphere appears to be coupled to the crust; under the Eastern Sierra Nevada, the mantle lithosphere is detached from the crust and is found at ~200 km depth. Above the eastern region, the Pliocene magmas appear to represent asthenosphere melts with the source depth decreasing from ~100 km to 40–75 km over time; in the Quaternary, the magmas have more a silicic composition, (Saleeby et al., 2012). The variation in melting source and depth is consistent with the prediction of the delamination models above, in which melt is first extracted from upwelling asthenosphere and later extends into the lower crust.In the Rift Valley subsidence and uplift events have been experienced in different regions. At the largest scale, the topography is characterized by two large lithospheric domes called the Afar and the East African domes. The average elevations are 1500m for the Afar and 1200m for the East African Dome.