9:50 You mention this, and your slide implies it, but the age of the canyons on the Colorado Plateau seem to all be in the 5-6 MYA range. This volcanism is in the same age range. Do you consider this evidence, or at least indicative, of when the Colorado was raised? For example, the Farallon Plate fracturing the basement, raising the plateau, and the mantle venting magmas around the edges? Also, other reading I've done has implied that explosive volcanism is silicic and water rich, and the water coming out of solution as the magma nears the surface and the containing pressure drops are what drive the detonation of the volcano. For a subduction zone volcano, that makes sense. You seem to believe that CO2 was the driver here, not water vapor. Yet the Farallon slab would have been water saturated. I wasn't really following what made you conclude CO2 was the culprit. Very interesting, BTW. Thank you for putting this together and uploading it. I enjoyed it.
Very cool. Best talk on US volcanism in a yr or 2
Nice and nerdy. Thanks! ;)
9:50 You mention this, and your slide implies it, but the age of the canyons on the Colorado Plateau seem to all be in the 5-6 MYA range. This volcanism is in the same age range. Do you consider this evidence, or at least indicative, of when the Colorado was raised? For example, the Farallon Plate fracturing the basement, raising the plateau, and the mantle venting magmas around the edges?
Also, other reading I've done has implied that explosive volcanism is silicic and water rich, and the water coming out of solution as the magma nears the surface and the containing pressure drops are what drive the detonation of the volcano. For a subduction zone volcano, that makes sense. You seem to believe that CO2 was the driver here, not water vapor. Yet the Farallon slab would have been water saturated. I wasn't really following what made you conclude CO2 was the culprit.
Very interesting, BTW. Thank you for putting this together and uploading it. I enjoyed it.