Citizen science opportunity - basaltic andesite sample collection

The central Oregon Cascades are unusual when compared to the rest of the Cascade volcanic range. This region of the Cascades is dominated by basaltic andesite, a volcanic rock of intermediate composition between basalt and andesite. Basaltic andesite has been the most prevalent type of lava erupted in the central Oregon Cascades for the past ~8 million years. It can be seen in many of the prominent skyline peaks of central Oregon, including North Sister, Black Butte, Mt. Washington, and Three Fingered Jack.

Despite the overwhelming dominance of basaltic andesite in this region, the chemical variability of these lavas has not been well documented. Are they related to basaltic lavas that have been erupted in the region? What geologic processes are responsible for generating and sustaining large volumes of basaltic andesite volcanism in this portion of the Cascades?

Alyssa Smith, PhD candidate at Portland State University, is studying these rocks to improve understanding of their geochemistry and the volcanic history of the central Oregon Cascades.

You can watch a recording of her recent COGS presentation here: On Basaltic Andesites: The Dominant Lava Type of the Central Oregon High Cascades

Alyssa has been collecting samples from many locations in central Oregon, but more locations remain to be sampled. Knowing that many COGS members enjoy hiking and might be willing to carry a rock hammer, we have worked with to Alyssa to develop this community sampling opportunity.