Scenes from last Sunday: Bishop Tuff and Volcanic Tableland, CA

Sunday was our first full day in the field. Here’s a few looks at my NOVA students doing geology out in eastern California. We spent the day on, and next to, the Volcanic Tableland north of Bishop, a massive stack of ash fall and ignimbrite deposits erupted from Long Valley Caldera 760,000 years ago: the … Read more

ACM

From “Volcanic Versus Anthropogenic Carbon Dioxide” by Terry Gerlach in the June 14, 2011 issue of EOS: Human activities emit ~135 times as much carbon dioxide as the world’s volcanoes? Holy cow.

The Big Bentonite just got smaller

The Shenandoah Valley of western Virginia records the switch in late Ordovician time from passive margin sedimentation associated with the Sauk and Tippecanoe epeiric seas, to active margin sedimentation associated with the onset of the Taconian Orogeny to the east. Higher up in the stack, a similar pattern is seen: a return to passive margin … Read more