BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Adventures in anisotropy at the base of the mantle: New constraint
 s on deep mantle dynamics - Maureen Long - University of Yale
DTSTART:20191113T160000Z
DTEND:20191113T170000Z
UID:TALK131299@talks.cam.ac.uk
CONTACT:Jenny Jenkins
DESCRIPTION:Observations of seismic anisotropy\, or the directional depend
 ence of seismic wavespeeds\, provide one some of the most direct constrain
 ts on the pattern of flow in the Earth's mantle. In particular\, as our un
 derstanding of crystallographic preferred orientation (CPO) of olivine agg
 regates under a range of deformation conditions has improved\, our ability
  to exploit observations of upper mantle anisotropy has led to fundamental
  discoveries about the patterns of flow in the upper mantle and the driver
 s of that flow. It has been challenging to develop a similar framework for
  understanding flow in the lowermost mantle\, even though there is convinc
 ing observational evidence for seismic anisotropy at these depths. New app
 roaches to the observation and modeling of lowermost mantle anisotropy\, i
 n combination with constraints from mineral physics\, are progressing towa
 rds interpretive frameworks that allow for the discrimination of different
  mantle flow geometries in different regions of D". In particular\, observ
 ational strategies that involve the use of multiple types of body wave pha
 ses sampled over a range of propagation azimuths enable detailed forward m
 odeling approaches that can discriminate between different mechanisms for 
 D" anisotropy (e.g.\, CPO of post-perovskite\, bridgmanite\, or ferroperic
 lase\, or shape preferred orientation of partial melt) and identify plausi
 ble anisotropic orientations. Ongoing improvements in seismic observationa
 l strategies\, experimental and computational mineral physics\, and geodyn
 amic modeling approaches are leading to new avenues for understanding flow
  in the deep mantle through the study of seismic anisotropy.\n\nReferences
 :\n1) Ford\, Heather A.\, and Maureen D. Long. "A regional test of global 
 models for flow\, rheology\, and seismic anisotropy at the base of the man
 tle." Physics of the Earth and Planetary Interiors 245 (2015): 71-75.\n2)R
 eiss\, M. C.\, M. D. Long\, and N. Creasy. "Lowermost mantle anisotropy be
 neath Africa from differential SKS‐SKKS shear‐wave splitting." Journal
  of Geophysical Research: Solid Earth 124.8 (2019): 8540-8564.\n3)Creasy\,
  Neala\, et al. "Constraining lowermost mantle anisotropy with body waves:
  a synthetic modelling study." Geophysical Journal International 217.2 (20
 19): 766-783.
LOCATION:Marine/Wolfson Building lecture hall\, Bullard Labs.
END:VEVENT
END:VCALENDAR