Upper Mantle Dynamics and
Quaternary Climate in Cratonic Areas
International Lithosphere Program (ILP) Regional Co-ordination
Committee CC
1/5
Geology and tectonics
Our present knowledge of the rheology of the lower crust is based
mostly on petrophysical inference from seismology and heat flow.
Continuous GPS observations of plate-wide strain, accompanied by
seismological investigations, and followed by continuum mechanical
modelling of GIA, seismic source and wave propagation, and studies of
the post-glacial faults offer a new entry and will add new insights
into the role and properties of the lower crust. Observations and
models of post-glacial or glacially induced faulting can help to
illuminate crustal stress fields and therefore crustal rheology issues.
On the lithosphere-mantle scale we expect, mostly on the basis of
on-going improvements and densifications of GPS observations, that the
fully 3-D observations, augmented by gravity (GRACE and GOCE) and sea
level change. Drawing from advances in thermodynamical and
climatological ice sheet modelling will retrieve laterally
heterogeneous structure of mantle and lithosphere from the observed
motions.
Current
GIA models are mostly based on radially (1D-)stratified Earth models
with linear rheology, though during the last few years progress has
been made in the development of global, 3D-stratified earth modelling.
However, due to computational restrictions, the latter models are
confined to relatively low resolutions.
Inversion of deep temperature data in boreholes provides a direct access to ground temperature histories during glaciation times. Kimberlite-hosted crustal and mantle xenoliths and seismic velocity models and controlled-source seismic experiments have yielded direct information on the composition and temperature of the lithosphere and asthenosphere
Inversion of deep temperature data in boreholes provides a direct access to ground temperature histories during glaciation times. Kimberlite-hosted crustal and mantle xenoliths and seismic velocity models and controlled-source seismic experiments have yielded direct information on the composition and temperature of the lithosphere and asthenosphere