The mantle reference frame defined by stationary hotspots has been used to determine the positions and motions of continental and oceanic plates surrounding the Caribbean region from late Jurassic time (140 m.y.) to the present. First, the position of the Pacific plate and the Pacific-Farallon spreading ridge has been reconstructed using the ages and geometry of island and seamount chains emanating from Pacific hotspots. Then, by assuming symmetric spreading across the Pacific-Farallon ridge, the motion of the Farallon plate relative to the mantle has been calculated. This shows that the postulated oceanic plateau which may form the core of the...