A volcanic eruption 260 million years ago covered half a million square kilometers. Isotope studies link it to the end-Permian extinction, the worst mass death in history.
Williamborg, CC BY-SA 3.0, via Wikimedia Commons
A Province Forged by Fire
In what is now Sichuan, China, an immense volcanic event began around 265 million years ago. This was not a single volcano, but a Large Igneous Province, or LIP. Over several million years, fissures in the Earth's crust unleashed vast quantities of basaltic lava, a process likely caused by a mantle plume, an upwelling of superheated rock from deep within the planet. The main eruptive period occurred between 262 and 261 million years ago.
These eruptions, known as the Emeishan Traps, originally covered an area estimated at up to 500,000 square kilometers. Today, the remaining volcanic rock covers about 250,000 square kilometers. The lava flows stacked up to create a "trap" landscape, named from the Swedish word trappa for "stairs," which describes the step-like hills formed by the erosion of successive basalt layers. The total volume of erupted material is estimated to be around 300,000 cubic kilometers, with thicknesses in some western areas reaching up to 5.5 kilometers. The province contains a variety of igneous rocks, including basalt, picrites, and more silica-rich rocks like rhyolites.
Architect of a Mass Extinction
The timing of the Emeishan Traps eruption aligns precisely with a global catastrophe: the end-Guadalupian (or Capitanian) mass extinction event, around 260 million years ago. This event, although smaller than the larger end-Permian "Great Dying" that followed millions of years later, ranks as one of history's most severe extinctions. The eruptions were a primary trigger.
The kill mechanism was lava and gases. The volcanoes released enormous volumes of gases into the atmosphere, including sulfur dioxide (SO2) and carbon dioxide (CO2). The SO2 would have formed sulfate aerosols, blocking sunlight and causing a sudden, short-lived "volcanic winter" accompanied by intense acid rain. Following this, the massive injection of CO2, a potent greenhouse gas, led to long-term global warming and severe ocean anoxia (a lack of oxygen) and acidification. Geochemical analysis of sedimentary rocks from this period reveals a major disruption to the global carbon cycle, showing the volcanism's devastating environmental impact. While the Emeishan event destabilized global ecosystems, the even larger Siberian Traps eruption about 8 million years later delivered the final blow of the Permian period.
💡Fun Facts
The name "Emeishan" is taken from Mount Emei (Emei Shan), one of China's Four Sacred Buddhist Mountains, which is carved from the province's volcanic basalt.
The characteristic step-like "trap" topography of the region is a result of the differential erosion of stacked, hardened lava flows.
The Emeishan basalts are a source of significant mineral wealth, containing world-class deposits of iron, titanium, vanadium, copper, and nickel that originated in the Earth's mantle.
By studying the magnetic alignment of minerals frozen in the lava, scientists can reconstruct the position of the tectonic plate of South China as it was 260 million years ago, near the equator.
The Mount Emei Scenic Area is generally open from 6:00 AM to 6:30 PM, with seasonal variations. Cable cars and temples within the park have their own specific operating hours.
Admission
A high-season entrance ticket is about ¥160 per person, which includes access to sightseeing buses. Cable cars and entry to specific temples like Wannian Temple carry separate fees.
Accessibility
The terrain is mountainous. While many paths are well-maintained, reaching the higher elevations involves steep climbs and many stairs. Cable cars are available to bypass some of the most strenuous sections, making areas like the Golden Summit more accessible.
