OREGON STATE UNIVERSITY

Stop 34: Co-Ignimbrite Ash

Co-ignimbrite ash

S22 52 13.71, W67 20 10.78

A co-ignimbrite ash is a cloud of fine ash particles that overrides a pyroclastic density current.The process responsible for the formation of these clouds is call elutriation. The co-ignimbrite deposit overlies the Tara ignimbrite and is capped with dilute flow, surge, and possibly flow deposits. This is the only co-ignimbrite ash deposit ever identified in the central Andes.

co-ignimbrite ash

Image of the co-ignimbrite ash deposit with Bob for scale.

Close up image of the co-ignimbrite ash deposit with hot sauce for scale.

See Sparks and Walker (1977) for more details