Impact melt sheet thermal modeling

In collaboration with Dr. Gavin G. Kenny (Swedish Museum of Natural History), I created a model to quantifiy how long it takes a melt sheet to cool after an impact event. Gavin visited the Boise State University Isotope Geology Lab to do CA-ID-TIMS U-Pb zircon geochronology on the Morokweng impact melt sheet, South Africa. We decided to build a thermal model in R of conductive cooling to better understand the overlapping high-precision ages. Our thermal model confirms that the melt sheet cools in tens of thousands of years and that it takes over a million years for the lithosphere to return to background geothermal conditions.

Figure of two-dimensional results from the conductive cooling model of the Morokweng impact melt sheet. Results for 0, 10, 20, 30, and 40 thousand years are presented and show the melt sheet cools from the top down and the central uplift stays hot for tens of thousands of years.

Here is an example of our results from the two-dimensional finite difference model. The code is highly flexible and can be easily adapted to simulate thermal perturbations of different shapes and scales.

Check out our paper to learn more:

Kenny, GG, Harrigan, CO, Schmitz, MD, Crowley, JL, Wall, CJ, Andreoli, MAG, Gibson, RL, Maier, WD. 2021. Timescales of impact melt sheet crystallization and the precise age of the Morokweng impact structure, South Africa. Earth and Planetary Science Letters. 567: 117013. https://doi.org/10.1016/j.epsl.2021.117013

View the code I developed on Mendeley Data or on GitHub.

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