Global observations of reflectors in the mid-mantle with implications for mantle structure and dynamics.

ABSTRACT: Seismic tomography indicates that flow is commonly deflected in the mid-mantle. However, without a candidate mineral phase change, causative mechanisms remain controversial. Deflection of flow has been linked to radial changes in viscosity and/or composition, but a lack of global observations precludes comprehensive tests by seismically detectable features. Here we perform a systematic global-scale interrogation of mid-mantle seismic reflectors with lateral size 500-2000 km and depths 800-1300 km. Reflectors are detected globally with variable depth, lateral extent and seismic polarity and identify three distinct seismic domains in the mid-mantle. Near-absence of reflectors in seismically fast regions may relate to dominantly subvertical heterogeneous slab material or small impedance contr

SUBMITTER: Waszek L 

PROVIDER: S-EPMC5786065 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature