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15 September 2023

Friday fold: Candler Formation

On a birding hike yesterday morning, I found this: This is a little slab of kinked phyllite of the Candler Formation. This metamorphic rock started as mud (and ash) deposited atop the Catoctin Formation, and it was later squeezed and heated during Appalachian mountain-building, encouraging the growth of micas at the expense of clay. A strong differential stress made sure those micas grew in one preferred orientation, and that resulted …


8 August 2023

Three new videos from Montana

I spent several enjoyable weeks in Montana last month, and shot some new video content there for my YouTube channel. Here are three videos that may be of interest to readers of this blog:


28 July 2023

Friday fold/fauxld duet from Glacier National Park

When is an apparent anticline not an fold? Find out on this week’s edition of the Friday Fold…