3 November 2017
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.