It is derived from the Swedish word for stairs ("trappa") and refers to the step-like hills forming the landscape of the region.
[2] The eruptions that produced the Emeishan Traps began 265 million years ago (Ma) or earlier.
The Emeishan basalts covers an area of more than 250,000 km2 with thicknesses ranging from several hundred meters up to 5.5 km (the average flood basalt thickness throughout the entire region is estimated to be around 700 m), but the Emeishan traps may have initially covered an area as much as 500,000 km2.
[8] Evidence suggests that the initial volcanism of the central Emeishan Traps occurred in a deep submarine environment without any significant prevolcanic uplift.
[9] The Emeishan Traps are associated with the end-Capitanian mass extinction event, the extinction of animal and plant life that occurred at the end of the Capitanian stage of the Guadalupian epoch of the Permian period.