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SUMMARY:Upper mantle thermochemical heterogeneity from coupled geophysical
 –petrological inversion of terrestrial and satellite data - Javier Fulle
 a - Complutense University of Madrid
DTSTART:20220601T150000Z
DTEND:20220601T160000Z
UID:TALK173156@talks.cam.ac.uk
CONTACT:Yihe Xu
DESCRIPTION:The lateral and vertical thermochemical heterogeneity in the m
 antle is a long-standing question in geodynamics. The forces that control 
 mantle flow and therefore Plate Tectonics arise from the density and visco
 sity lateral and vertical variations. A common approach to estimate the de
 nsity field for geodynamical purposes is to simply convert seismic tomogra
 phy anomalies\, sometimes assuming constraints from mineral physics. Such 
 a converted density field does not match in general with the observed grav
 ity field\, typically predicting anomalies\, the amplitudes of which are t
 oo large. Knowledge on the lateral variations in lithospheric density is e
 ssential to understand the dynamic/residual isostatic components of the Ea
 rth’s topography linking deep and surface processes. The cooling of ocea
 nic lithosphere\, the bathymetry of mid oceanic ridges\, the buoyancy and 
 stability of continental cratons or the thermochemical structure of mantle
  plumes are all features central to Plate Tectonics that are dramatically 
 related to mantle temperature and composition. We present a new global the
 rmochemical model of the lithosphere and underlying upper mantle constrain
 ed by state-of-the-art seismic waveform inversion\, satellite gravity (geo
 id and gravity anomalies and gradiometric measurements from ESA's GOCE mis
 sion)\, surface elevation and heat flow data: WINTERC-G. The model is base
 d upon an integrated geophysical-petrological approach where mantle seismi
 c velocities and density are computed within a thermodynamically self-cons
 istent framework\, allowing for a direct parameterization in terms of the 
 temperature and composition variables. The complementary sensitivities of 
 the data sets allow us to constrain the geometry of the lithosphere-asthen
 osphere boundary\, to separate thermal and compositional anomalies in the 
 mantle\, and to distinguish dynamic vs isostatic surface-elevation contrib
 utions. At long spatial wavelengths\, our model is generally consistent wi
 th previous seismic (or seismically derived) global models and earlier int
 egrated studies incorporating surface-wave data at lower lateral resolutio
 n. At finer scales\, the temperature\, composition and density distributio
 ns in WINTERC-G offer a new state of the art image at a high resolution gl
 obally (225 km average inter-knot spacing).
LOCATION:ONLINE - Details to be sent by email
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