The Patom crater ('Kolpakov cone')
A cone of broken limestone with a central knoll in the taiga of Irkutsk Oblast, described by geologist Vadim Kolpakov in 1949.
1949 CE · 59.28, 116.59 · status: disputed
The account
Its strange ring shape has been blamed on a meteorite, a fragment of the Tunguska body, a deep gas blowout and volcanic activity. Local people avoided the place. Tree-ring work suggests it formed only a few hundred years ago.
The sceptical view
Most recent studies favour a geological (endogenous) origin; there is no evidence of an impact.
The researched reading
A strange cone in the Siberian taiga, a few centuries old. A deep gas outburst through limestone is the leading scientific explanation; the exact process is still studied.
| Explanation | Weight | Why |
|---|---|---|
| A known natural phenomenon | 50% | Geological studies (2006 Institute of Geochemistry, gravimetric and geoelectric surveys) favour an endogenous origin: a rapid outburst of deep fluids and gases (CO₂, water vapour) through fractured limestone forming a cone, a few hundred years ago. |
| A poorly understood natural phenomenon | 20% | The exact mechanism of formation is still debated, and the crater’s unusual shape and youth are not fully explained. |
| Undetermined | 20% | The share a generic explanation had beyond what has been shown for this case: it fits many cases like this one, but has not been demonstrated for this one. |
| Something known, misidentified | 3% | No witnesses; misidentification does not apply. |
| Genuinely anomalous | 3% | Claims of a meteorite or "alien reactor" are unsupported; geology explains it reasonably well. |
| Secret human technology | 2% | No human activity could have formed it 300 years ago. |
| Perception, memory or mind | 1% | Local fear and legends do not affect the crater’s origin. |
| A hoax or fabrication | 1% | The crater exists and has been studied. |
Official position: Russian geologists at a 2010 conference rejected the meteorite hypothesis and favoured a geological, deep-gas origin.