Friday fold: soft sed def in Kodiak
The Friday fold is a seaside outcrop of soft sediment deformation (not post-lithification tectonic deformation) on Kodiak Island, Alaska.
folds
Guest post: Turtle Mountain and the infamous Frank Slide
A guest post by Nicholas Rossi, a student in Callan’s Canadian Rockies field course. Turtle Mountain is located in the Blairmore Range in Alberta Canada about 160km south of Calgary. It is the site of the Frank Slide, a landslide of over 90 million tons of rock that gave way on Turtle Mountain’s East side … Read more
Friday fold: Kinked limestone laminae, Consolation Lakes
The Friday fold is a kink fold in thinly-laminated limestone from the same site as yesterday’s mysterious orange oncoids.
What those geologists were looking at
Yesterday, I showed you a scene of geologists (including me) clustered around some (presumably interesting) outcrop. I asked what you thought we might be looking at. Howard Allen, a denizen of this part of the globe, immediately identified the scene as that of the downstream end of the Athabasca Glacier. Several people guessed that we … Read more
Friday fold: lower Martinsburg Formation near Bixler’s Ferry
The Friday fold is presented in photo, annotated photo, and GigaPan formats. It’s a cleaved anticline in lower Martinsburg Formation limy slate from Page County, Virginia. See if you can spot Mr. E. coli in the GigaPan!
Deformed carbonatite dikes in Cambrian slate, Yoho National Park, British Columbia
Callan’s Canadian Rockies field course visits an outcrop of Cambrian slate in Yoho National Park, British Columbia. Folded and boudinaged carbonatite dikes are seen.
Friday fold: Spray Mountain Group siltstone
Today, we return to Banff National Park, to the outcrops next to the parking area for Bow River Falls… Zoomed-in closer to the thinner layers at left: These strata (shale and siltstone) were laid down in the quiet aftermath of the Permo-Triassic extinction, as terranes colliding with the edge of North America (far to the … Read more
Structures seen at Floe Lake
A showcase of geologic structures observed between downpours of rain at Floe Lake, Kootenay National Park, British Columbia. Cleavage, bedding, folds, faults, and strain are all presented for the discerning structural reader’s edification and titillation.
Friday fold: scenes from the trail to Bertha Lake
Given that I’m leaving tomorrow for the Canadian Rockies, I’ve been inspired to look through some of my photos from last summer, and to realize how few of them I’ve blogged so far. So let me show you some folded things today that Lily and I saw the afternoon we arrived at Waterton Lakes National … Read more
Granite dikes that have been folded and boudinaged
It seems like a good morning to return to Ontario, and to the Archean shear zones exposed at the Quetico/Wabigoon subprovince boundary of the Superior Craton. Readers will hopefully recall that I spent several days absorbing structural goodness from these rocks on a field trip before the Minneapolis GSA meeting last fall. The trip was … Read more
Friday fold: Franciscan chert in Golden Gate Park
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
Friday fold: an asymmetric anticline from Wyoming
Another landform seen out the window of that very productive photo-flight last March: That’s a breached plunging anticline – doubtless a Laramide structure. This was over Wyoming; I think here. Looking north-ish, along the axis of the fold: Note that the lengths of section line A and B are not equal: this anticline is asymmetric. … Read more
Friday fold: Brienz, Switzerland
Today’s fold comes to us from the Alps, courtesy of blog reader “Earth Mama.” She says: Attached is a photo of the outcrop, near Brienz, Switzerland, and a GE screenshot of the location. I saw this as I was looking out the train window, and was able to grab my camera in time. Best I … Read more
Friday fold: Hoh Hoh Hoh
Another guest submission for the Friday fold – this is becoming a major trend! Peter Selkin‘s student Rick Schwartz loaned us this one. Peter describes the outcrop this way: The rocks here are Miocene turbidites of the Hoh lithic assemblage (sometimes called the “Hoh Terrane”) exposed at Beach #4 on the Pacific coast of the … Read more
Plane views: Wyoming
I wanted to pick up where I left off months ago with some airplane photos as I was flying back from my California field class (over spring break). All views are to the north (out the left side of the airplane as we flew from Reno to Minneapolis). We crossed from northern Nevada into Wyoming, … Read more
Friday fold: Pofadder shear zone
The Friday fold “guest fold” series continues with a folded ultramylonite from South Africa.
Friday fold: Bedford Canyon Fm., California
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
Friday fold: boxiness in Oman
Max Arndt contributed this week’s Friday fold: (click on the image to get to a larger sized version on Max’s Flickr page) That’s the Warah Formation exposed on the Batain Coast of northeastern Oman. This is the thrust front of a thin-skinned fold and thrust belt. I think it’s just lovely! Max has a ton … Read more
Friday fold: ball & pillow in volcanic ash
Another guest Friday fold – this one supplied by Ander Sundell of the College of Western Idaho, and his student Katie Ursenbach, who took the shot and gave permission for me to re-post it here. You’re looking at cuspate-lobate folds due to primary sedimentary settling. the Snake River Canyon in southwestern Idaho. A pile of … Read more
Exquisite boudinage in Ontario
Callan shares images of extraordinary boudinage outcrops in strained Archean meta-basalts on the Quetico-Wabigoon subprovince boundary within the southern Superior Craton. Ogle these gorgeous structures in awe and wonder.