19 October 2018

Friday fold: the Brooks Range, Alaska

Posted by Callan Bentley

Today is another reader-contributed Friday fold:

Riia Chmielowski. a Senior Research Engineer/Laboratory Manager at the Laser-Ablation ICP-MS Laboratory, Lulea University of Technology in Sweden.

Riia writes,

Here are three from my Master’s work in the Brooks Range. My field area was the West Fork of the Atigun River, in the Brooks Range, Alaska.

I note that these images carry a special charm, since they are scanned from slides. That’s the way we used to take field photos, kids!

Riia’s descriptions follow…

Photo A12 is of the ridge labelled Fold 2A and Fold 1 A on figure 3 of the attached paper, and is approximately located at 68.245509, -149.521162 (according to GoogleMap’s “what’s here” button).

Here is the figure she references:

Zooming in on the fold:

Annotated to show the trace of bedding in red:

Photo E14 is of the set labelled Fold 1B, 2B, 3B on that figure, and is approximately located at 68.240801, -149.550688

Zooming in on the folds:

Here’s my armchair annotation of that one – Hopefully I’ve sussed the trace of bedding out correctly!

Photo H23 is of the segment of the Kayak Shale just north of the label “Panel B” in that figure (approximately 68.244300, -149.541418), and shows parasitic folds that are only visible in perfect lighting conditions. That photo was taken from camp, and most days that summer that was a featureless black hillside.

Zooming in on the folds:

And, a set of annotations, showing the trace of bedding in white:

Thanks for sharing, Riia!

Other readers: Do you have cool folds to share with the Mountain Beltway audience? If so, shoot me an email to share them: cbentley at nvcc dot edu. Thanks in advance!

Happy Friday to all. Enjoy the weekend.