17 June 2011
Friday fold: a granite dike
Posted by Callan Bentley
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 composite) picture bigger by clicking it:
Here’s the texture of the dike granite:
Here’s the texture of the host rock granite:
And here’s another look at the host granite, in the hinge area of an antiform in the folded dike. Notice how much more foliated it is in this high-strain area:
This outcrop also featured a series of small fractures arranged in sets:
Some of these fractures showed a small amount of offset where good marker units were present:
Folds and faults! …It must be your lucky day…
[…] visiting the folded granite dike that served as last Friday’s featured fold, my Tuesday field trip (a week ago yesterday) with Chuck Bailey and Jay Kaufman took us to […]
[…] relatively linear structure that has since been folded as you see above. In the other pictures from Professor Bentley’s 2011 post – along with the higher-resolution version of the above composite image – you can see […]