Figure 2.

(a) Hotspot island formation in the stagnant lid regime of mantle convection. An island considerably larger than a typical hotspot island today can be constructed by continuous magma input from a stationary mantle plume. (b) Two contrasting fates of hotspot islands in early plate tectonics. Those formed on young ocean floor would have subsided as quickly as present-day hotspot islands, whereas those on older ocean floor could have been subaerial on a longer time scale because of subdued seafloor subsidence. See text for further explanation.