Friday fold: west Bighorn monocline

While out in the field with Butch Dooley last week, making major discoveries like I do, I was very impressed with the landscape-scale west Bighorn monocline, which takes formerly horizontal Madison limestone and skews it to a westward dip where the mountains end and the intermontane basin begins. It’s totally sweet. Check it out in photo form and gigapan, too.

Friday fold: a granite dike

This Friday, I give you a fold from the shores of the Rockfish River, south of Charlottesville, in Virginia’s Blue Ridge basement complex, and just down the road from the Lawhorne Mill High Strain Zone. The fold distorts (and improves) a felsic dike cutting the darker granite of the basement. You can make this (stitched … Read more

Friday fold(s): the Outdoor Lab

Today’s Friday fold takes me back 25 years, to when I visited the Outdoor Lab with my science class in Arlington County Public Schools. I revisited this exemplary outdoor education facility on Tuesday, at the invitation of its director, Neil Heinekamp. Neil wanted a geology “expert” to take a look at their rocks, and I … Read more

Friday fold(s): More kinky phyllite, but this time from the field

Last week, the Friday fold featured a kinked phyllite of unknown provenance that is currently resident in David King Hall 2074 on the campus of George Mason University. However, on Tuesday of last week, I found another kinked phyllite, this one out in the real world, at Thoroughfare Gap, in the Harpers Formation of the … Read more