The RRR triple junction at the southern end of the Pacific-Cocos East Pacific Rise
Abstract
A Sea Beam survey of the Pacific-Cocos-Galapagos triple junction at 2°40'N on the East Pacific Rise (EPR) establishes that it is a ridge-ridge-ridge junction, with the EPR axis making a small but sharp bend where it is intersected by a slow-spreading (15 mm/yr) fast-propagating rift. At the tip of the narrow triangle of crust accreted at this slow-spreading axis is volcanic ridge built on EPR crust. Tholeiitic lavas erupted along the slow-spreading axis, here and at the rather similar Pacific-Nazca-Galapagos junction, differ in minor element and rare earth element geochemistry from lavas on adjacent segments of the EPR axis, being slightly enriched in incompatible elements.
- Publication:
-
Earth and Planetary Science Letters
- Pub Date:
- March 1992
- DOI:
- 10.1016/0012-821X(92)90075-7
- Bibcode:
- 1992E&PSL.109...73L
- Keywords:
-
- Bathymeters;
- Ocean Bottom;
- Pacific Ocean;
- Plates (Tectonics);
- Tectonics;
- Crustal Fractures;
- Geochemistry;
- Geodynamics;
- Lava