
We report diverse shock-metamorphosed and melted grains from the 1908 airburst site in Russia. Analysis of samples from a rimmed crater-like feature near the epicenter revealed microspherules, carbon spherules, glass-like carbon, and melted minerals. In addition, quartz grains exhibit high-temperature melting and shock metamorphism, including planar deformation features (PDFs) and planar fractures (PFs), with some showing glass-lined internal fractures and melted silica coatings. These grains indicate high shock pressures (≥2 GPa) and temperatures (≥1710°C), consistent with proposals that fragments from the Tunguska airburst struck the Earth’s surface at velocities sufficient to produce shocked quartz. These findings advance our understanding of airburst/impact mechanics, but because few people have ever observed a dangerous airburst like Tunguska, very little is known about them. Lacking sufficient real-world data, scientists should continue modeling these dangerous low-altitude airbursts to understand them better. The Tunguska event is a valuable case study demonstrating the urgent need to improve our planetary defense strategies.
airbursts, comets, asteroids, impact craters, shocked quartz, shock metamorphism, hydrocode modeling, meltglass, microspherules
airbursts, comets, asteroids, impact craters, shocked quartz, shock metamorphism, hydrocode modeling, meltglass, microspherules
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