Rheological controls on the emplacement of extremely high-grade ignimbrites

Extremely high-grade, lava-like welded ignimbrites are produced by many large explosive eruptions with volumes typically 101–103 km3. However, understanding of the physical properties of these unusual deposits, and their transport and depositional mechanisms, is incomplete. The lava-like and rheomorphic Grey’s Landing ignimbrite, Idaho (western United States), provides abundant field evidence supporting the upward migration of a transient