ABSOLUTE MIGRATION OF PACIFIC BASIN MID-OCEAN RIDGES SINCE 85 MA AND THEIR TECTONIC IMPLICATIONS FOR THE PACIFIC PLATE

Mid-ocean ridges are major physiographic features that dominate the world seafloor. Their absolute motion and tectonics are recorded in magnetic lineations they created. The absolute migration of mid-ocean ridges in the Pacific basin since 85 Ma and their tectonic implications was investigated in this work and the results indicates that at about anomaly 21 (47 Ma) the East Pacific Rise (EPR) and Juan de Fuca ridge experienced an abrupt change in their migration direction that persisted until about anomaly 6 (20 Ma), probably due to changes in subduction-zone configuration in the northern Pacific. This may represent a period of tectonic instability for the Pacific plate during which the EPR was probably subducted beneath the North American continent. This period culminated by the appearance of the Galapagos propagator and a major reorganization of the East Pacific Rise south of the Galapagos