27 July 2018

Friday fold: new folds from the Empire Formation, Glacier National Park

Posted by Callan Bentley

Hiking Siyeh Pass in Glacier in Glacier National Park on Tuesday with my Montana State University field course, we spotted a few new folds in the Empire Formation (a transitional unit between Helena Formation and Grinnell Formation).

Here is one of the students serving as a sense of scale, with interesting features on either side of him:

On the left, there are small scale folds in a regular little train:

Note the cleavage in the central shaly unit in this part of the outcrop – it is subvertical on the left (west), but then leans over to dip to the west on the right (east):

Here’s another site, a little bit further down the trail, showing another example of small-scale folding:

Happy Friday to all! We’ll be spending our day driving back to Bozeman after a successful field course.