Pyroclast (from the Greek words for “fire” and “broken”) is the collective term for all fragmented material ejected by a volcano. This includes everything from fine volcanic ash and dust to medium-sized Lapilli and large volcanic bombs or blocks torn from the surface rocks. ANSWER: (C) Pyroclast
What is the collective term for the lava and fragments of surface rocks obtained as a result of a volcanic eruption? (A) Lapilli (B) Scoria (C) Pyroclast (D) Breccia
Share
When a volcano erupts explosively, it shatters magma and surrounding rock into millions of fragments. These are collectively called pyroclastic materials or Tephra. They are classified by size: ash is less than 2mm, lapilli are 2-64mm and bombs are larger than 64mm. These materials can travel at high speeds as “pyroclastic flows,” which are gravity-driven clouds of hot gas and debris that destroy everything in their path. The study of pyroclastic deposits allows geologists to reconstruct the history and intensity of ancient eruptions.