Key Takeaways:

  1. A crescent-shaped crater in Northeast China, known as the Yilan crater, is now identified as Earth’s largest impact crater formed within the last 100,000 years.
  2. This discovery followed the confirmation in July 2021 that a geological structure in the Lesser Xing’an mountain range resulted from a space rock impact.
  3. The Yilan crater measures 1.15 miles across and is estimated to have formed roughly 46,000 to 53,000 years ago, based on radiocarbon dating.
  4. Researchers unearthed evidence of the impact, including melted and recrystallized rock fragments, shocked quartz, and teardrop-shaped glass fragments.
  5. Crescent-shaped impact craters are rare on Earth, and investigations are underway to understand the missing portion of the Yilan crater’s southern rim.
(Image credit: NASA Earth Observatory image by Lauren Dauphin, using Landsat data from the U.S. Geological Survey.)

In a groundbreaking discovery, scientists have identified Earth’s largest impact crater formed in the last 100,000 years. Located in Northeast China, the Yilan crater boasts a distinctive crescent shape, spanning an impressive 1.15 miles in diameter.

This remarkable geological structure emerged from the collision of a space rock with our planet, an event estimated to have occurred between 46,000 to 53,000 years ago, as indicated by radiocarbon dating of charcoal and organic lake sediments extracted from the site.

Prior to this revelation, the sole recognized impact crater in China was situated in Xiuyan county, Liaoning province. The confirmation of the Yilan crater‘s extraterrestrial origin in July 2021 marked a pivotal moment in Earth’s geological history. The findings were published in the esteemed journal Meteoritics and Planetary Science, shedding light on this extraordinary natural phenomenon.

Beneath the sedimentary layers of lakes and swamps, researchers unearthed a colossal slab of brecciated granite, nearly 1,000 feet thick. This distinctive type of granite comprises an amalgamation of fragmented rocks bonded together in a matrix, bearing unmistakable signs of meteorite impact.

Evidently, some fragments displayed evidence of melting and subsequent recrystallization, a consequence of the intense heat generated during the impact. Others featured “shocked” quartz, exhibiting a distinctive pattern of fracturing induced by the force of the space rock’s impact.

Further examination revealed teardrop-shaped glass fragments and glass pieces punctured with minuscule bubbles, both indicative of a high-intensity impact event. The missing section of the Yilan crater’s southern rim contributes to its crescent-shaped appearance when viewed from above, a rare feature in terrestrial impact craters. A Landsat-8 satellite image captured the crater’s northern rim in October 2021, spurring scientists to delve into the mystery of the vanished southern rim.

The former record-holder for the largest impact crater less than 100,000 years old, the Meteor Crater in Arizona, pales in comparison. Estimated to be between 49,000 to 50,000 years old, it spans a diameter of 0.75 miles. In contrast, the Xiuyan crater, measuring 1.1 miles across, surpasses both its Arizona counterpart and the newly revealed Yilan crater, though its precise age remains a mystery.

This recent discovery in Northeast China not only broadens our understanding of Earth’s geological history but also underscores the awe-inspiring forces that have shaped our planet.

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