As I’ve mentioned previously, I spent some time making GigaPans this summer out west. Here’s Lily and me on the crest of the Bridger Range, enjoying the clear skies and great geology: When this portrait was taken (by our friend Lindsay), I was shooting this GigaPan: link Try exploring it to see if you can … Read more
The Friday fold returns to Canada this week, with a look at an internally crumpled mountain along Alberta’s Kananaskis Trail…
One thing that’s 100% worth doing if you find yourself visiting Natural Bridge, Virginia, is to pop in for a visit at Foamhenge, an art installation a few miles away. Foamhenge is a full-scale replica of Stonehenge, made of styrofoam (covered in gray latex paint). It’s a few years old now, so it’s begun to … Read more
Today, a view to the southwest, from close to the hinge of the main anticline in the Sandy Hollow area, a classic geological field mapping locality in southern Montana: Triassic-aged Dinwoody Formation dominates the main part of the scene. Note how the strike and dip of the positively-weathering strata wrap around. Our Rockies students mapped … Read more
Two Z folds from the Proterozoic rocks of the Laramie Range, Wyoming – you get two since I’ve been so delinquent about blogging over the past month.
First sample of the summer – a new “pocket fold” showing Paleoproterozoic deformation in the northern Laramie Range, Wyoming.
Happy Friday! Here’s a view of the folded contact between the (older, lower) New Market Formation, and the (younger, upper) Lincolnshire Formation, as exposed in Staunton, Virginia: The contact has been folded, pretty intensely: The New Market Formation is massive, light-colored, and exhibits fenestral texture here. The Lincolnshire is darker, more thinly-bedded, and is chock … Read more
This is my final post on the pre-GSA-Minneapolis structural geology field trip to the Superior Province. The photo above shows a roadcut exposure of boudinage in xenolith-bearing Vermillion Granitic Complex. Here’s another, smaller, more brittle example of boudinage, from another site, the following morning: Gee, it only took me 1.5 years to blog that trip … Read more
Yesterday we examined primary sedimentary structures (including trace fossils) at an outcrop of Devonian-aged Brallier Formation turbidites between Deerfield and West Augusta, Virginia. Today, we’ll zoom in on the tectonic structures at the site: folds, faults, and joints. Remember, you don’t have to take my word for it. You can explore it for yourself in … Read more
Last weekend, after we checked Lily in for her race, I spotted some boulders near the check-in site. The next morning, once the race had started but before we could cheer her on, my field assistant and I went back to the boulders to check them out. My field assistant’s planners had forgotten to pack … Read more
Following on yesterday’s post about the kink bands within the strained metagraywacke of the Laurel Formation in DC, let’s take the opportunity today to go to Klingle Valley, site of a different facies within the Laurel Formation: a strained metaconglomerate. Though the exposure isn’t as great as the Purgatory Conglomerate, I think you’ll find plenty … Read more
Last week before GSW, I spent several pollen-choked hours in Rock Creek Park, GigaPanning some of the rocks of the Rock Creek Shear Zone. Here are some exposures in the bed of Broad Branch that show lovely kink banding. In at least one spot, you can see a conjugate pair, so these rocks were (1) … Read more
The Friday fold combines a moment of insight on a field trip in the Archean Superior Province and a new paper published this month in the journal GEOLOGY.
Today, let’s go back to the Pike Dam, where we spent some lovely moments last week, agog at the lovely graded beds and flame structures visible there. In contrast, today we want to examine the deformational structures seen elsewhere at this same outcrop. There are folds and faults and joints and more exotic fare: tension … Read more
Two years ago, I took a trip to the Phoebe Hall Knipling Outdoor Lab, which is Arlington, Virginia’s outdoor education facility in the Pond Mountains (southern continuation of the Bull Run Mountains), on the eastern edge of the Blue Ridge geologic province. I was invited back last week to look at some new exposures. I … Read more
More folds from the charismatic Noonday Dolostone in Mosaic Canyon, Death Valley National Park, California: Annotated: Happy Friday!
Callan and his colleague Jay Kaufman (University of Maryland) go to extraordinary lengths to document an intriguing block of rock in northern Virginia’s Blue Ridge province. Great images and a lot of fun result – but what do these rocks tell us?
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.
Another scene from the South Page Valley Martinsburg outcrop featured here last week: a slightly mud-bedecked example of plumose structure. This plume occurs within a single graded bed (turbidite) of the Martinsburg Formation. It gets younger (paleo-up) to the right. The joint propagation that the plumose structure records began somewhere vertically above the area of … Read more
No time for more details than that – sorry! Happy Friday and a restful weekend to all!