Editor's Summary

9 October 2008

Oceanic lithospheric accretion at faults

Oceanic detachment faults are associated with one of two contrasting modes of accretion at mid-ocean ridges and can accommodate extension for millions of years. The main mode of accretion has been thought to be symmetrical, dominated by magmatic processes with subsidiary high-angle faulting and the formation of abyssal hills on both flanks. The other is asymmetrical involving active detachment faults along at least one ridge flank. Escartin et al. present an examination of approximately 2,500 km of the mid-Atlantic ridge that reveals that asymmetrical accretion surprisingly occurs along half of the studied ridge section. Much of the variability in seafloor morphology, seismicity and basalt chemistry found along slow-spreading ridges may thus be attributed to the frequent involvement of detachment faults in oceanic lithospheric accretion.

LetterCentral role of detachment faults in accretion of slow-spreading oceanic lithosphere

J. Escartín, D. K. Smith, J. Cann, H. Schouten, C. H. Langmuir & S. Escrig