Zhamanshin Crater, Kazakhstan

Lot Description:
This slab of impactite has a vitreous quality due to its high silica content. Vesicles are abundant. There are two broad cut faces and a natural external edge delimits the form. Melting is evident in the swirling, rippled materials which range in hue from tan to taupe in this product of a devastating asteroid impact. Modern cutting.
149 x 129 x 13mm ( 5.75 x 5 x 0.1 in)
263.9g (0.5 lb)

Impactites are terrestrial rocks that have been impacted by asteroids or comets. Following such events, earth rock is melted, shattered or shocked. At times even new minerals including microdiamonds are formed as a result of these high-pressure events. Impactite may be found on or beneath the floor of the crater, in the rim, or in ejecta (material launched from the crater following an impact). As might be imagined, impact craters are identified as a result of the presence of impactite, as well as other diagnostic impact products such as shatter cones and impact glass.

The Zhamanshin crater is the site of the most recent asteroid impact event of sufficient magnitude to create a climate shift akin to a nuclear winter — but not sufficiently powerful to have caused a mass extinction. The crater is 14 kilometers in diameter and the impact that created the crater occurred in the Pleistocene approximately 900,000 years ago. While there are different impact products found in proximity to Zhamanshin Crater — including pure glass — this is a cut slab of impact-melt rock containing natural glass as a result of the extraordinary heat generated by the explosive impact.

Christie's would like to thank Dr. Alan E. Rubin at the Institute of Geophysics and Planetary Physics, University of California, Los Angeles for his assistance in preparing this catalogue.