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Abstract Giant planet migration appears widespread among planetary systems in our Galaxy. However, the timescales of this process, which reflect the underlying dynamical mechanisms, are not well constrained, even within the Solar System. As planetary migration scatters smaller bodies onto intersecting orbits, it would have resulted in an epoch of enhanced bombardment in the Solar System’s asteroid belt. Here, to accurately and precisely quantify the timescales of migration, we interrogate thermochronologic data from asteroidal meteorites, which record the thermal imprint of energetic collisions. We present a database of⁴⁰K–⁴⁰Ar system ages from chondrite meteorites and evaluate it with an asteroid-scale thermal code coupled to a Markov chain Monte Carlo inversion. Simulations require bombardment to reproduce the observed age distribution and identify a bombardment event beginning$$11.{3}_{-6.6}^{+9.5}\, {\mathrm{Myr}}$$ $11.3_{-6.6}^{+9.5}\mathrm{Myr}$after the Sun formed (50% credible interval). Our results associate a giant planet instability in our Solar System with the dissipation of the gaseous protoplanetary disk. 

Abstract Subglacial calcite precipitation is thought to occur in East Antarctica during periods when warm Southern Ocean waters access the ice sheet margin. Here we present an expanded precipitate archive that includes a continent‐wide compilation of 38 new and previously reported calcite²³⁴U‐²³⁰Th ages with isotopic compositional data. These data are interpreted to record periods when interior meltwaters are exported to the ice sheet margins as a result of ice acceleration and thinning. An assessment of coincidence between²³⁴U‐²³⁰Th dates, ranging from 16 to 256 ka, and peaks in Southern Ocean temperature yields a statistically significant correlation. Additional comparison of precipitate dates and climate data finds that calcite formation and ice acceleration cluster within periods of enhanced millennial scale climate variability as well as high global ice volume. This sensitivity to background climate is consistent with the hypothesis that these factors exert some control on ice sheet response to changes in climate.