On Monday, my field course students and I tried to find the Poleta folds, but I had failed to figure out in advance the best access point. Oops. That’s the way the cookie crumbles, when you’ve got big plans but not enough time to enact them with appropriate pre-planning. We had some happy exploration of … Read more
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
Yesterday I flew from DC to Reno, Nevada in the company of 11 students, and then we rented vehicles and drove south on Route 395, one of the greatest roads in America, to Bishop, California, where we area based for the next 3 days. We’re doing a regional field geology course examining the extraordinary rocks, … Read more
In the White Mountains of eastern California, just west of the Deep Springs Basin (site of my coldest camping experience ever, followed by a memorable morning walk in the playa and discovery of a bat mummified by salt), there lies a classic field mapping location, the Poleta folds. Here’s what it looks like from Google … Read more
I got to San Francisco on Saturday afternoon, flying in on the same flight from DC as Rob Simmon and Maria-José Viñas. MJ and I took the BART downtown, and then met up with Jess Ball for Thai dinner and a yummy dessert of banana wrapped in roti with Nutella and coconut ice cream. Then, … Read more
My man Walcott contributed a lot of images to the USGS stockpile during his travels. Today, I’ll feature one from Bishop, California, from 1894: Got it from here. Rock hammer on the left for scale. The caption reads: Plicated layers of thin bedded chert in limestone etched by erosion, Lower Cambrian (?). Hill two miles … Read more
At last weekend’s northeastern / north-central GSA meeting in Pittsburgh, David Saja of the Cleveland Museum of Natural History presented a talk entitled, “Geometric Analysis of Folded Greywacke Layers from Pacheco Pass, California.” [Abstract link] In addition to the standard PowerPoint presentation that 99% of GSA speakers use, David also brought in some hand-samples (what … Read more
A year and a half ago, on my way back to Modesto from Yosemite, I pulled over at the side of the road and found a piece of urbanite full of whoppers. But that curiosity wasn’t what caught my eye and made me pull over in the first place. Instead, what I noticed was this: … Read more
The Friday fold is a series of strata underwater near California’s famed “Mavericks” surf break.
I didn’t mention it yesterday, but there was one other structure that I saw at my newest outcrop on New 55. This is it: That’s a bunch of fractures. The broken rock is being altered by preferential fluid flow through the fractures. The fluid is not inert; it’s chemically active, and reacting with the rock. … Read more