Temporal and petrogenetic constraints on volcanic accretionary processes at 9-10 degrees north East Pacific Rise

Abstract

Volcanic accretion at the fast-spreading East Pacific Rise (EPR) occurs over a ~2-4 km wide neo-volcanic zone on either side of the axial summit trough (AST). Eruption ages are critical for understanding the distribution and timing of volcanic and magmatic activity. Uranium series nuclides are susceptible to fractionation by magmatic processes that occur beneath mid-ocean ridges, and the half-lives of

Reconciling geochemical and geophysical observations of magma supply and melt distribution at the 9°N overlapping spreading center, East Pacific Rise

“…Vertical ascent of these melts through the crust between the two ridge axes results in the formation of the wide sill‐like lens beneath and to the west of the east limb of the OSC. This melt can provide a source for the relatively young off‐axis volcanism between the two limbs [ Nunnery et al , 2008; Waters , 2010] and the abundant volcanic edifices within the OSC basin [ White et al , 2009]. This distribution of melts over a wider region within the crust, may result in spatial and temporal fluctuations in magma supply to the shallow melt lens, allowing for the formation of high‐silica lavas during periods of diminished melt delivery and mixing of diverse range of melt compositions.…”