FOLDS   FOLDS
Austerlitz Phyllite
Berkshire County, Massachusetts

The rainbow is a quartz-rich layer in this metamorphic rock composed of very small grains of mica, chlorite, and quartz. Before metamorphism it was a thin layer of silt in mud. Stress in Earth's crust caused the rock to deform by folding. The relatively stiff quartz-rich layers formed broad, gentle folds, while weaker mica- and chlorite-rich layers folded into crinkles with a much shorter wavelength. Folds in rocks occur in all sizes from tiny ones like these up to monsters with dimensions measured in miles, yet their shapes tend to be remarkably similar at all scales.

Crossed polarizers with gypsum plate

splendor_s_bw18.gif - 5630 Bytes


| Tour Home | Next Page | Next Page

| Splendor Home | Gallery | SlideShow |Exploring Rocks |


Museum Open Monday-Saturday: 9:30 am to 5 pm | Carousel Hours: 10 am to 4:30 pm
Office of Cultural Education | New York State Education Department
Information: 518-474-5877 | Contact Us | Image Requests | Terms of Use
Join us on Facebook See us on YouTube See us on Flickr