10 June 2016
There are some structural goodies here at the confluence of the Rapid River and the Salmon River in west-central Idaho. I visited these outcrops three weeks ago on a field trip after the Rocky Mountain section meeting of GSA. The rocks are the Lightning Creek Schist, a schist that’s part of the Wallowa Terrane, an accreted chunk of crust that docked with western North America during the Mesozoic.
Here is the trace of foliation:
And here it is folded, with a few veins thrown in for good measure:
Folded vein at center:
This next one has a lot of structure going on…
Now let’s zoom in to three areas of that image for some close-ups:
Nearby, there was some sweet boudinage to be seen with a vein segment:
Note the blocky bottom margin of the vein and the way the foliation warps upward into the boudin neck:
Two views of a fold expressed partly in 3D:
A small squidge’um nearby:
Next up, a big vein catches the attention, but then let’s zoom in to the recess just above it…
And let’s close with this lovely isoclinal fold…
That should satisfy your appetite for deformation for at least an hour or so. Happy Friday!