title: Crustal plates in the central atlantic.
abstract: Various people have proposed that North and South America are a part of a gigantic crustal plate within which little differential movement is taking place. Considerations of the size of this postulated plate and the pattern of seismicity around the Caribbean indicate that it is in fact two plates, separated in the region between the Lesser Antilles and the Mid-Atlantic Ridge. Many of the offsets of the Mid-Atlantic Ridge opposite the Caribbean are the result of differential spreading rates and the westward continuations of the fracture zones extending from these offsets are active left-lateral faults.
authors.forename: M M
authors.initials: MM
authors.lastname: Ball
authors.forename: C G
authors.initials: CG
authors.lastname: Harrison