Question Concerning Meteorite Ejecta Travel

Question

I was researching more into the studies done by Kjaer and his team ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6235527/ ) concerning the hypothesis about the Younger Dryas impact crater named Hiawatha in Greenland and its dating. Another study by Pino et al. ( https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6416299/ ) proposes that some of the Younger Dryas Boundary located in Chile could potentially be associated with the impact of Hiawatha and travel of impact ejecta.

Regardless of the pending measurements of the exact age of the meteoric rock located under the Ice Sheet to confirm age, my question is this: did the ejecta travel through the atmospheric circulation, which I find to be a possibility due to the polar vortex air currents carrying it over the North Pole, or was it simply from the explosive force which the meteorite was theorized to fall with? I know that with eruptions like St. Helens volcanic ash can circulate far and wide through the atmosphere, but with the amount found in Chile would this more line up with a blanketing of ejecta or just trace amounts finding its way there?

Kjær KH, Larsen NK, Binder T, Bjørk AA, Eisen O, Fahnestock MA, Funder S, Garde AA, Haack H, Helm V, Houmark-Nielsen M, Kjeldsen KK, Khan SA, Machguth H, McDonald I, Morlighem M, Mouginot J, Paden JD, Waight TE, Weikusat C, Willerslev E, MacGregor JA. (2018). A large impact crater beneath Hiawatha Glacier in northwest Greenland. Sci Adv. 2018 Nov 14;4(11):eaar8173. doi: 10.1126/sciadv.aar8173.

Pino, M., Abarzúa, A. M., Astorga, G., Martel-Cea, A., Cossio-Montecinos, N., Navarro, R. X., Lira, M. P., Labarca, R., LeCompte, M. A., Adedeji, V., Moore, C. R., Bunch, T. E., Mooney, C., Wolbach, W. S., West, A., & Kennett, J. P. (2019). Sedimentary record from Patagonia, southern Chile supports cosmic-impact triggering of biomass burning, climate change, and megafaunal extinctions at 12.8 ka. Scientific reports, 9(1), 4413. https://doi.org/10.1038/s41598-018-38089-y

Answer 1

The research doesn't provide enough information to specify the displacement process of a 0.1mm spherule over 12,000 kilometers from North Greenland to Chile.

If the suggested impact was from Greenland, the space rock would have hit 800 to 1200 meters of ice at perhaps 10km/s which is the average for that kind of event.

Mount St Helens was about 0.25 km³ of ejecta, and the Greenland impact was a lot higher, i.e. 20km³ of vaporized rock.

Volcanoes send the energy out over many hours, whereas a YD meteorite would convert the energy relatively fast, perhaps mostly in the first 2 seconds. The thermal energy would have been very high, and the ejecta would have reached every level of the stratosphere, and the earthquakes would have emptied some lakes out in North America and left some major destruction fields in North America.

The same atmospheric displacement effects for all kinds of recent volcanoes would have been out measured considerably by a YT event.

Perhaps further studies will change the impactor site from the Greenland one which is perhaps 200k years old, to one in the Southern Hemisphere. At the moment, the evidence is so fleeting that the Nature article you gave has only generated a few lines of text on Wiki.