By: magic-gigapans
Image: Chris Johnson, Mid-Atlantic Geo-Image Collection
License: Creative Commons Non Commercial ⧉

Uploaded: 13 May 2020
Last Updated: 15 May 2020

436 megapixels
29,052 x 15,012 pixels
96.8 in X 50.0 in at 300dpi
230 pixels per inch

This outcrop can be found along the Difficult Run Trail north of Georgetown Pike. The camera is pointed south. This is part of the Mather Gorge Formation, a Proterozoic metagraywacke. This outcrop is an example of early stages of partial melting in action. As the graywacke underwent high grades of metamorphism some of the minerals (particularly quartz and feldspars) began to melt and reform. In this image the differential erosion highlights the quartz that has melted and reformed. It is more resistant than the rest of the graywacke. Because of this it stands out. This migmatite and others like it are the result of tectonic collisions during the Taconic and Acadian Orogenies.