What is the term for a volcanic deposit consisting of unsorted mixtures of ash, pumice, rock fragments, and hot gases moving rapidly down the slope of a volcano?

💡 Solution & Explanation

A pyroclastic flow is a high-density, rapidly moving gravity current composed of superheated gas, ash, and rock fragments that cascades down volcanic flanks during explosive eruptions. Distractors such as pahoehoe refer to smooth, fluid basaltic lava flows, while lahars describe mudflows consisting of volcanic debris and water. Temperatures inside a pyroclastic flow can exceed seven hundred degrees Celsius.