Tectonics on a sphere: the geometry of plate tectonics - The Solid Earth - page 34

(b)

Figure 2.19. (b) Four volcanic island chains in the Pacific Ocean. The youngest active
volcano is at the southeast end of each chain. (From Dalrymple et al. (1973).)

(c)

Plume

M a n tl e

F l o w -li n e

H o t s p o t tr a c k

P l a t e

Past Present

Time

Figure 2.19. (c) A demonstration of the relative motions between the hotspot (fixed
in the mantle) and the seamount chain on the overriding plate. The pencil represents
the hotspot, which is fixed in the mantle (rectangular grid). The plate moves over the
mantle and the pencil marks the line of seamounts (the 'hotspot track'). The star is
the position of a seamount. After formation of the seamount, the plate moves north
for one unit and then west for one unit so leaving a solid (pencil) line of seamounts,
the hotspot track. The 'flow-line', the relative motion of the plate with respect to the
hotspot, is the dashed line. (Reprinted with permission from Nature (Stein Nature
387 , 345-6) Copyright 1997 Macmillan Magzines Ltd.)