Australia’s Ancient Asteroid Strike and 5km Megatsunami: The Jeerinah Impact Event

Somewhere in Earth’s distant past, a cataclysmic asteroid impact shook the planet, leaving behind a trail of devastation so immense that its effects are still recorded in the rocks of Western Australia. Yet, despite the overwhelming evidence, the crater remains missing, swallowed by billions of years of geological change. This is the story of the Jeerinah Impact Event, one of the largest asteroid collisions in Earth’s history, a moment when a cosmic behemoth crashed into our world, unleashing an apocalyptic mega-tsunami between two to five kilometers high that surged across Earth’s primordial oceans. This video will explore the extensive evidence uncovered in multiple peer-reviewed studies, revealing the extraordinary events that took place 2.63 billion years ago in or near the Pilbara Craton of Western Australia. You can find links to the studies used to construct this video in the description.

The Jeerinah Impact Layer, or JIL, is one of the most compelling pieces of evidence for this ancient catastrophe. Preserved within the Jeerinah Formation of the Fortescue Group, this impact ejecta layer contains microkrystite spherules and microtektites, tiny droplets of molten rock that condensed from a vaporized cloud following the asteroid’s impact. These microscopic clues are packed with iridium, an element rare on Earth but abundant in asteroids. They also contain nickel-rich phases and platinum group element anomalies, unmistakable signatures of extraterrestrial origin. Some quartz grains within the JIL display planar deformation features, which only form under the extreme pressures generated by an asteroid strike. These geological fingerprints are eerily similar to those found at other confirmed impact sites, including the Chicxulub crater, the event that wiped out the dinosaurs.

The asteroid that created the Jeerinah Impact Layer is estimated to have been between ten and twenty kilometers in diameter, placing it in the same class as the impactor that ended the reign of the dinosaurs. The energy released by this event was incomprehensible, equivalent to millions of nuclear explosions, vaporizing the impact site, sending superheated debris across the globe, and setting fire to the sky. Despite this devastation, the exact location of the crater remains a mystery. Over 2.63 billion years, plate tectonics, erosion, and sedimentary processes may have obliterated the impact site. Some scientists propose that the asteroid struck an ancient ocean, with the resulting crater being consumed by tectonic shifts. Others believe the crater may still lie buried beneath the Pilbara region or offshore, hidden beneath layers of sedimentary rock.

One of the most striking consequences of the Jeerinah impact was the mega-tsunami that followed. The force of the asteroid's collision with the Earth displaced an unimaginable volume of water, sending waves up to five kilometers high surging across the planet’s primordial oceans. These tsunamis left behind evidence in the form of massive breccia deposits found in the Carawine Dolomite of the eastern Hamersley Basin. Geological records show enormous boulders, some the size of small buildings, that were ripped from the seafloor and thrown onto distant shores. Disrupted sediment layers indicate violent water movement, with entire sections of the ocean floor being torn apart and redeposited. The hydraulic pressure of the tsunami was so great that it injected microkrystite-bearing mud deep into fractures in the rock, providing further proof of the event’s sheer force. Drill cores from the eastern Hamersley Range and areas around Marble Bar reveal thick sequences of chaotic sediments that preserve the destructive power of this ancient tidal wave.

The Jeerinah impact may have played a crucial role in shaping Earth's iron deposits. At the time of the impact, the planet’s oceans were rich in dissolved iron, a world of rust-red waters under an atmosphere devoid of significant oxygen. The turbulence caused by the impact and its resulting mega-tsunami may have stirred deep iron-rich waters, bringing them into contact with surface environments that were intermittently oxygenated by early photosynthetic microbes. This chemical reaction could have triggered the widespread precipitation of iron, contributing to the formation of the Marra Mamba Iron Formation, one of Australia’s most significant sources of iron ore. The deposition of Banded Iron Formations, or BIFs, appears to coincide with major asteroid impacts throughout Earth’s history, suggesting that cosmic collisions may have played a pivotal role in the creation of the vast mineral resources that are mined today.

The reach of the Jeerinah impact may not have been limited to Western Australia. Thousands of kilometers away, in South Africa, geologists have identified impact ejecta layers within the Monteville Formation of the Transvaal Supergroup. These spherule layers closely resemble those found in the Jeerinah Formation, suggesting that both regions were affected by the same asteroid impact. At the time, the Pilbara Craton and the Kaapvaal Craton were likely part of an ancient supercontinent known as Vaalbara. This means the impact ejecta from the Jeerinah event was distributed across vast distances, leaving its mark on multiple continents. The discovery of matching spherule layers in two distant cratons strengthens the hypothesis that a single massive asteroid collision was responsible for the Jeerinah Impact Layer in Australia and the Monteville Formation in South Africa.

The Jeerinah Impact Event was a cataclysm of unimaginable scale, one that reshaped the planet and left behind a geological record that still tells its story over two and a half billion years later. Though its crater remains hidden, the evidence of its devastation is undeniable. From impact spherules packed with extraterrestrial material to the remains of an ancient mega-tsunami, the traces of this cosmic disaster are preserved in the rocks of Western Australia and beyond. The connection between asteroid impacts and banded iron formations suggests that these catastrophic events may have played an essential role in shaping Earth's natural resources. The correlation between the Jeerinah impact and similar spherule layers in South Africa hints at the possibility of a world-altering collision that affected an entire supercontinent.

As scientists continue to investigate this ancient impact, the search for the missing crater remains one of the great geological mysteries of our time. Future discoveries may reveal its location, further cementing the Jeerinah Impact as one of the most significant cosmic events in Earth's history. This is the story of an asteroid strike so powerful that it altered the face of the planet forever, an event whose echoes are still recorded in the rocks beneath our feet. Understanding the Jeerinah Impact Event not only unlocks the secrets of Earth’s past but also serves as a reminder of the immense power of the universe and the ever-present potential for cosmic forces to shape our world in ways we can scarcely imagine.

Here's the video we made on the Jeerinah Impact Event (JIL) on the OzGeology YouTube channel: