Friday Rocks #43: Mega Ptygmatic Folds

Mega ptygmatic folds
Mega ptygmatic folds

The above photo is taken from a field trip in 2010 to Death Valley and surrounding mountains / desert. This stop was Monarch Canyon. We (the students) are standing at a cliff edge, looking across a gorge at the opposing cliff wall. That’s the best scale I can give you for this. It’s huge, it’s awesome.

Advertisements

Friday Rocks #42: Mylolisthenite

Charlevoix mylolistelite
Charlevoix mylolistelite

The injecting mylolisthenite (pale-green rock filling fracture) was created during a meteor impact. It can be found near Charlevoix, Quebec (19T 407510.00 m E, 5260539.00 m N). Find out more about the Charlevoix impact crater in an old upsection post.  Mylolisthenite is a fine grained breccia which contains various clasts in a non-melt matrix (differentiating it from pseudotachylite).