In the Central Pacific Basin, an abandoned, NE trending spreading ridge is evident on the satellite gravity map and is confirmed in bathymetric and magnetic data. Our identification of magnetic anomaly lineations flanking the abandoned ridge suggests that between chrons M21 (147 Ma) and M14 (135 Ma) it was the plate boundary between the Pacific plate and a microplate, which we here name the Trinidad microplate. The configuration of the Pacific-Farallon-Phoenix triple junction until chron M22 (149 Ma) was fault-fault-ridge (FFR). After chron M22, the Pacific-Farallon-Phoenix triple junction changed its configuration. The reorganization of the triple junction led to the birth of the Trinidad microplate in its vicinity. Around chron M15 (136 Ma), the spreading ridge between the Pacific plate and the Trinidad microplate was abandoned and the Magellan microplate was born and remained active till chron M9 (128.5 Ma). After welding of the Magellan microplate to the Pacific plate, the triple junction had a ridge-ridge-ridge (RRR) configuration until the major reorganization around chron M0 (120 Ma). ¿ 1998 American Geophysical Union