Massive 900-Metre Crater Discovered in Guangdong, China

Researchers have unveiled the Jinlin crater, a remarkable impact structure located on a hillside in Guangdong Province, near Zhaoqing City, China. This newly identified crater, measuring between 820 and 900 metres in diameter and reaching a depth of 90 metres, is not only significant due to its size but also because of its relatively young age, having formed during the Holocene epoch approximately 11,700 years ago.

The discovery of the Jinlin crater is particularly noteworthy, as it adds to the limited number of confirmed impact craters worldwide, currently estimated at around 200. Prior to this finding, the largest known impact structure from the Holocene was Russia’s 300-metre Macha crater. Researchers believe that the Jinlin crater was created during the early to mid-Holocene, as indicated by soil erosion measurements in the surrounding area.

Surprising Preservation Despite Climate Challenges

The existence of such a large and well-preserved crater is unexpected, given the climatic conditions of the region. Guangdong Province is known for its regular monsoons, heavy rainfall, and high humidity—conditions that typically accelerate erosion and could have obliterated any visible crater over time. Remarkably, the Jinlin crater remains intact, shielded by thick layers of weathered granite that have protected its structure from erosive forces.

The crater’s extraterrestrial origin is supported by specific geological features found within the granite. Researchers discovered numerous quartz fragments displaying planar deformation features, which are microscopic characteristics indicative of impact events. These features arise under extreme pressure conditions, ranging from 10 to 35 gigapascals, levels that far exceed those produced by Earth’s geological processes. Such intense shockwaves are solely the result of hypervelocity collisions with extraterrestrial objects.

While researchers have confirmed that the impactor was a meteorite rather than a comet—given that a comet would have created a crater at least 10 kilometres wide—they have yet to determine the composition of the meteorite, whether it is iron or stone. Significant work remains to fully understand the implications of this discovery.

Implications for Impact History

The Jinlin crater challenges existing assumptions about the frequency and scale of recent impacts on Earth. The planet’s surface is theoretically subject to equal bombardment from space debris, yet geological variations result in different rates of erosion for impact evidence. As a result, some craters may vanish entirely, while others, like Jinlin, endure. This uneven preservation skews our understanding of Earth’s impact history.

Interestingly, confirmed craters often cluster in regions with well-funded geological research programs. The discovery of the Jinlin crater in a remote, forested area suggests that many more impact structures could remain unidentified in less-studied locations.

As ongoing research continues at the Jinlin crater, it has the potential to provide new insights into the frequency of significant impacts on our planet. Additionally, it may inform scientists about what factors contribute to the preservation or destruction of the evidence left behind by these cosmic events.