Magmatism in the Garrett transform fault (East Pacific Rise near 13°27′S)

Abstract

The Garrett transform is characterized by recent (zero age) volcanic activity located within the active tectonic domain of the transform valley at depths greater than the 3500 m. This intratransform volcanic activity contributed to the formation of constructional edifices forming ridges (>300 m in height) and small mounds (<20 m in height) built near slivers of serpentinized peridotites. The erupted lavas are depleted mid ocean ridge basalts (MORBs) with low ratios of K/Ti (0.02-0.11), Zr (30-100 ppm), Y (18-50 ppm), and (La/Sm)N (0.25-0.60). In order to explain the restricted range of compositional variabilities and the absence of the enriched basalts produced by prior melting, it is postulated that even though they were produced, these most enriched end-member lavas did not reach the surface; instead, it is proposed that these melts contribute to the formation of impregnated mantle material in the lithosphere. -from Authors