Geo 730: August 21, Day 598: Spotting Our Quarry

Another view of the back wall of the Quartzville Road quarry, showing the horizontal columns that allow us to infer a dike cutting through. And my presumption, which is quite tentative, is that the lighter areas are less weathered and stained, suggesting that the dike is rhyolitic in composition. And it's the altered rhyolite that shows the most interesting minerals. I'm not sure I have a decent photo of it, but you can also find very fine black tourmaline crystals here, which suggests a high temperature during mineralization.

Photo unaltered. July 9, 2012. FlashEarth Location.