Magmatic and tectonic extension at the Chile Ridge: Evidence for mantle controls on ridge segmentation

• DOI: 10.1002/2016gc006380
• Publication Date: 2016-05-27T23:52:50Z
• Authors: Samuel M. Howell; Garrett Ito; Mark D. Behn; Fernando Martinez; Jean‐Arthur Olive; Javier Escartín
• Keywords: Ridge push; Mid-Atlantic Ridge; Hotspot (geology); Detachment fault

Abstract We use data from an extensive multibeam bathymetry survey of the Chile Ridge to study tectonomagmatic processes at ridge axis. Specifically, we investigate how abyssal hills evolve axial faults, variations in magmatic extension influence morphology and faulting along spreading axis, these correlate with segmentation. The are used estimate fraction plate separation accommodated by normal faulting, remaining extension, M , is attributed primarily accretion. Results show that ranges 0.85 0.96, systematically increasing first‐order second‐order segment offsets toward centers as depth axis shoals relative flanking highs valley. Fault spacing, however, does not geometry, morphology, or Ridge, which suggests observed increase tectonic strain ends achieved through increased slip on approximately equally spaced faults. Variations segments follow petrologic indicators mantle melt fraction, both showing a preferred length scale 50 ± 20 km persists even much longer segments. In comparison, mean relief fail significant correlations distance offsetting These two findings suggest form segmentation partially decoupled geometry boundary. hypothesize this arises cells buoyantly upwelling mantle, up.