The rise consists of three large volcanic massifs, Tamu, Ori, and Shirshov, but, in contrast, there are few traces of magmatism on the surrounding ocean floor.
[8] Scientific studies of the size, shape, and eruption rate of the Shatsky Rise have concluded that the rise originated from a mantle plume, whereas studies of magnetic lineations and plate tectonic reconstructions have shown that it must have originated near a triple junction and drifted up to 2,000 km (1,200 mi) during the Early Cretaceous (140–100 Ma).
[9] Shatsky Rise formed at a triple junction, but the thickness of the plateau coupled with the depth and intensity of melting is different from those of MORB (mid-ocean ridge basalt), making a recycled mantle slab a more likely source.
[3] The Shatsky Rise LIP erupted at the location of the Pacific–Farallon–Izanagi triple junction c. 147–143 Ma either because a mantle plume reached the surface or because of decompression melting at a mid-ocean ridge.
The eruption coincided with an 800 km (500 mi), nine-stage jump in the location of the triple junction and a configuration change from ridge-ridge-ridge to ridge-ridge-transform.
[3] The conjugates of the Shatsky and Hess rises on the Farallon Plate were most likely involved in the Laramide orogeny; the former subducted beneath North America and the latter below northern Mexico.