3 November 2017

Friday fold: More kinks from Glacier National Park

Posted by Callan Bentley

This Friday, let’s return to Glacier National Park. Here are some folds in Helena Formation limestone:

Can’t see them? Fair enough – the point of maximum inflection appears to be hidden behind a snow-filled gully:

But in addition to that big fold, there are several kink bands in there, too. Let’s zoom in:

Here they are:

Zooming in further, on the right-most of these kink bands:

…And here, with the traces of bedding highlighted:

These strata are Mesoproterozoic. The folding is probably Cretaceous or Paleogene in age (related to the Sevier Orogeny).

Deep time, rocks that tell stories with multiple chapters: Good fodder for a Friday fold!

Enjoy your weekend.