My former student James O’Brien recently moved out to the left coast, and posted some photos earlier this week of a hike he took at Mount Diablo State Park in the mountains east of the San Francisco Bay area of California. There are some classic-looking Franciscan cherts exposed there, as these folded examples show: Seeing … Read more
The Friday fold is some crumpled sedimentary rock near the Hayward Fault in California.
Marek Cichanski (of De Anza College near the south end of San Francisco Bay) contributed this week’s Friday fold: Marek says: The locality is a place near San Francisco called Devils Slide. It is a piece of the coastal highway built along a steep mountainside above the ocean. This unstable stretch of road was recently … Read more
A guest post today for the Friday fold from my former student Naseem Naghdi, who’s now in southern California: The Ventura Avenue anticline is a fault-propogated fold and is located in the core of (Conoco’s) San Miguelito oil field, which is on the Ventura-Rincon anticlinorium. Carbon dating of seashells have indicated that the terraces range … Read more
More folds from the charismatic Noonday Dolostone in Mosaic Canyon, Death Valley National Park, California: Annotated: Happy Friday!
For the Friday fold today, let’s return to the warmth of Mosaic Canyon in Death Valley National Park, California: Can you see it there? Let’s zoom in on the dark area in the middle of that first photograph…. Ahh! Now that’s a fold to end the week on! Enjoy the weekend, everyone.
The Accretionary Wedge is a ~monthly geoblog “carnival” which elicits posts on a variety of themes. This month, it’s Maitri’s turn, and she wants to hear about our geo-injuries. Here’s my story: In 2003, I was doing field work in the high Sierra, mapping the Sierra Crest Shear Zone for my geology master’s degree. When … Read more
Following the “monster” that was the Friday fold two weeks ago, here are some more folds in the Noonday Dolostone (“Dolomite”) in Mosaic Canyon, Death Valley, California: Zooming in on this isoclinal fold: Bedding traces annotated, highlighting the “similar” style of folding (hinge thickened; limbs thinned): A very different style of folding, observed a few … Read more
While out in Death Valley with my Field Studies students last March, we encountered an extraordinary fold in Mosaic Canyon. Check this thing out: The rock is the Noonday Dolostone (“Noonday Dolomite” in mineralogically biased argot). It may be hard to make out what’s what there… So let me assist with a little annotation, tracing … Read more
Some of the dynamics of small-scale mass wasting in granular materials are captured in this animated GIF from sand dunes in Death Valley.
South of Searles Lake is a distinctive landform: the Trona Pinnacles. This multi-image photomosaic is too small for GigaPan, but I’ve made a medium-sized version of it that can be hosted here. You’re going to have to click through to see it large, though. Click to enlarge These are tufa towers (like we saw at … Read more
These are exposed on the road leading in to Death Valley from the Panamint Valley to the west. That’s all I’ve got time for today, folks – gotta get to work.
This image is from the canyon in which route 168 ascends the Inyo Range from Big Pine, California. View is to the south/southwest. Those are gravel layers that dip gently westward. I think they’re associated with the underlying Waucobi Lake Beds, which are Plio-Pleistocene in age. The lake beds are made of finer stuff, but … Read more
Today, we take a look at an outcrop of young, basically unlithified sediments east of Bishop, California, on the way out Poleta Road, toward the White Mountain Research Station’s Owens Valley Lab, where you can get a nice view of the Coyote Warp Relay Ramp. These photos were taken just west of the bridge over … Read more
All seen last March in Death Valley, at Mesquite Dunes…. within ten minutes of one another.
Callan hosts the 357th installment of the popular satellite imagery / geologic search game “Where on (Google) Earth?”
In the delivery room last week, while we waited for Lily’s labor to ramp up, I finished reading The Omnivore’s Dilemma, by Michael Pollan. I think it was one of the most insightful, important books I’ve ever read. I was pre-disposed to like it, because I really enjoyed Pollan’s earlier book The Botany of Desire, … Read more
This week, the Friday fold comes to us courtesy of fellow AGU-hosted geoblogger Jessica Ball: That’s chert cropping out in Golden Gate Park, San Francisco. Maybe you should check it out in December when you’re in the Bay area for the AGU Fall Meeting? Outcrop location: Lat/Long: 37.771517,-122.4777. Annotated version: Recall there are more chert … Read more
A few shots from Fossil Falls, in the southern Owens Valley, California… This is the now-dry river bed of the Owens River. There’s abundant evidence of water-induced erosion (potholes, polishing, etc.), but nary a drop of water to be seen – Though this particular portion of the Owens River drainage dried up in the Pleistocene, … Read more
Another guest submission for the Friday fold: Callan – Please find enclosed a collection of photos you could possibly use for a future Friday Fold blog post. The following photos were all taken by me on Sunday, April 29th, in the vicinity of Bedford Peak and the Maple Springs Trailhead (Silverado Canyon Road), Cleveland National … Read more