The Earth is bombarded by thousands of micrometeorites every day, but only once in tens of millions of years does an asteroid large enough arrive to leave a lasting mark on the geography of a region and the geology of its underlying rocks. The Popigai Crater in northern Siberia, located about 550 kilometers north of the Arctic Circle, is the result of one such impact event.
The Popigai Crater was formed about 35 million years ago when an asteroid, estimated to be 5 to 8 kilometers in diameter, slammed into what is now the Taymyr Peninsula of northern Siberia, Russia. The impact instantly melted some 1,750 cubic kilometers of rock, about half of which was ejected into the atmosphere. Some of this material travelled high into the air and landed thousands of kilometers away on other continents, leaving behind a crater roughly 100 kilometers wide and 8 to 10 kilometers deep.
A digital elevation model shows the topography of the crater and the surrounding area. Credit: NASA
The region where the asteroid struck is rich in a type of metamorphic rock composed of garnet, graphite, and the minerals that form gneiss (typically feldspar, quartz, and mica). The graphite-garnet gneiss basement rock was overlain by about 1.5 kilometers of sedimentary cover. The asteroid blasted through this sedimentary layer and into the underlying gneiss, where the immense heat and pressure caused the flakes of graphite in the Archean graphite-garnet gneiss to be instantaneously transformed into diamond.
The heat and pressure generated by the impact rippled through the surrounding rocks, melting everything in their path. At a distance of about 12 kilometers from the point of impact, the conditions were likely still too extreme for diamonds to form or survive. Just beyond this zone, around 13 kilometers out, the temperature and pressure dropped enough to allow the formation of stable diamonds. This created a shell of diamond-bearing rock, about 1 to 2 kilometers thick, shaped like a hemisphere around the impact point. Researchers estimate that this shell had a volume of roughly 1,600 cubic kilometers and contained more diamonds than all of Earth’s other known deposits combined.
The question that arises now is whether these diamonds can be mined. The answer is no.
Did you know, there is another crater of diamonds in Arkansas, the United States, where you can search for diamonds and keep what you find? Go read about the Crater of Diamonds in Murfreesboro
During the Popigai impact, the conditions necessary for diamond formation existed only for an instant. This momentary flash of heat and pressure converted flakes of graphite in the Archean graphite-garnet gneiss into diamond. Many of the resulting diamonds were small polycrystalline stones, roughly the same size and shape as the original graphite flakes. Most are tiny, less than 2 millimetres across, and suitable only for industrial applications, such as the production of diamond abrasives. Because these diamonds formed in a brief pulse of extreme temperature and pressure, there was no time for large, single-crystal stones of high clarity and purity to develop. For this reason, there are no gemstone-quality diamonds within the Popigai Crater.
LANDSAT image from NASA of Popigai Crater in Siberia, Russia. Credit: Wikimedia Commons
Moreover, for industrial purposes, synthetic diamonds are preferred because they are far cheaper to produce. According to a 2010 report by the U.S. Geological Survey, “natural diamond accounts for about 1.4% of all industrial diamond used.” In that year, worldwide production of synthetic industrial diamond was approximately 4.38 billion carats, valued between $1.65 billion and $2.50 billion—an average price of roughly 50 cents per carat or less.
In addition, the Popigai Crater lies in a remote region above the Arctic Circle, an inhospitable environment lacking infrastructure, workforce, and logistical support. It is therefore economically unfeasible to mine a site that would yield diamonds we can already produce more cheaply in laboratories.
The Popigai crater is the fourth largest verified impact crater on Earth. The three larger craters are either buried (Chicxulub), deformed (Sudbury), or severely eroded and deformed (Vredefort). Popigai has only been slightly modified by erosion, leaving it as one of the most well-preserved craters in the world.
New evidence suggests that the impact event might be linked to the Eocene–Oligocene extinction event, which occurred around 34 million years ago. This period marked one of the most significant global climate shifts of the Cenozoic Era, when the Earth cooled rapidly, leading to the formation of the Antarctic ice sheet and the extinction of many species, particularly among marine plankton and mammals. While multiple factors, such as volcanic activity and changes in ocean circulation, likely contributed to the upheaval, the Popigai impact may have compounded these stresses by injecting vast quantities of dust and aerosols into the atmosphere, temporarily darkening the sky and disrupting global climate patterns.
References:
# Diamonds Beneath the Popigai Crater, Geology.com
# Russia’s Crater of Diamonds, NASA
# Russia's Popigai Meteor Crash Linked to Mass Extinction, Live Science
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