The Fifteen-Twenty fracture zone (or FTFZ, Cabo Verde fracture zone, 15°20' fracture zone),[1][2][3] is a fracture zone located on the Mid-Atlantic Ridge (MAR) in the central Atlantic Ocean between 14 and 16°N. It is the current location of the migrating triple junction marking the boundaries between the North American, South American, and Nubian plates.[4][5] The FTFZ is roughly parallel to the North and South America—Africa spreading direction and has a broad axial valley produced over the last ten million years by the northward-migrating triple junction.[4][5] Offsetting the MAR by some 175 km (109 mi), the FTFZ is located on one of the slowest portions of the MAR where the full spreading rate is 25 km (16 mi)/Ma.[6]