Tuya

A tuya is a flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet.

As lava that erupts under a glacier cools very quickly and cannot travel far, it piles up into a steep-sided hill.

Discovering and dating the lava flows in a tuya has proven useful in reconstructing past glacial ice extents and thicknesses.

If the volcano breaches the surface of the glacier it will be topped by a subaerially erupted lava plateau.

Tuya Butte is a near-ideal specimen of the type, the first such landform analyzed in the geological literature, and this name has since become standard worldwide among volcanologists in referring to and writing about these formations.