Stop 33: The Filo Delgado Ignimbrite & The Tara Ignimbrite

This location shows a wonderful section of the Filo Delgado overlying the Tara ignimbrite. The Filo Delgado Ignimbrite is the youngest unit and contains those distinguishable fiamme of obsidian. The middle unit is the Filo Delgado fall deposit that contains banded rhyolites, obsidian clasts and is dominated by lithics. The oldest deposit, underlying the Filo Delgado is the Tara ignimbrite that has an ashy matrix, lithics, and no obsidian and/or rhyolite.

It was questionable whether the fall deposit should be associated with the overlying Filo Delgado or with the underlying Tara ignimbrite. Because the plinian contains obsidian and rhyolite, it has been suggested to be part of the Filo Delgado deposit.