OREGON STATE UNIVERSITY

Stop 2: Lava Domes

Lava Domes  22°14'45.85"S  67°35'28.28"W

Laguna Colorada domes from southwest

Effusive dacitic domes erupted after the ignimbrite emplacement cover the center and extend down the southern edge of the Laguna Colorada shield.  The youngest domes appear to be in the center of the shield.  The central domes show heavy hydrothermal alteration.  You can see spectacular panoramas of the domes looking north across the Salar de Chalviri from Puripica Chico, as seen in the above picture.  A road following the western edge of the lava domes connects the northern and southern roads and offers panoramic views of Laguna Colorada.

At ignimbrite shields, lava domes erupt after the ignimbrite is emplaced and cover any evidence for collapse near the vent.  This greatly complicates things and scientists are left to find creative methods of studying vent regions of ignimbrite shields.  For example, volcanologists at the Cerro Panizos shield have used the orientation of magnetic crystals to observe collapse structures.