Аннотация
Large meteorite impacts, such as the one that created the Vredefort
structure in South Africa similar to2 Ga ago, result in significant
heating of the target. The temperatures achieved in these events
have important implications for post-impact metamorphism as well
as for the development of hydrothermal systems. To investigate the
post-impact thermal evolution and the size of the Vredefort structure,
we have analyzed impact-induced shock heating in numerical simulations
of terrestrial impacts by projectiles of a range of sizes thought
to be appropriate for creating the Vredefort structure. When compared
with the extent of estimated thermal shock metamorphism observed
at different locations around Vredefort, our model results support
our earlier estimates that the original crater was 120-160 kin in
diameter, based on comparison of predicted to observed locations
of shock features. The simulations demonstrate that only limited
shock heating of the target occurs outside the final crater and that
the cooling time was at least 0.3 Myr but no more than 30 Myr.
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