Thermal controls of crustal diapirism: implications for the earliest crust and sub-cratonic lithosphere

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Thermal controls of crustal diapirism
implications for the earliest crust and
sub-cratonic lithosphere
Catherine Robin Richard Bailey
Neutrino Geoscience Sudbury, 2008
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• Implications
• Predominantly vertical (diapiric) crustal
  tectonics in the Early Earth but also
• Supplies metabasalts to the lower crust to form
  TTGs (tonalites, trondhjemites and granodiorites)
• Leaves a depleted restite which can be
  harzburgitic to dunitic (for komatiitic
  volcanism), and which can accumulate from the
  top-down to form the SCLM (sub-cratonic
  lithospheric mantle), without calling on large
  plumes or strong horizontal plates (but doesnt
  preclude some of these)
• The plausibility of vertical tectonics (and the
  transition to modern-day tectonics) depends on
  the assumed heat source distribution and mode of
  volcanism of the early earth, and on its
  evolution with time.

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