Integrative Natural History of the Blue Ridge Province, Part 1: High Ground on South Mountain | Michaux State Forest, Pennsylvania, USA
Taken atop Pole Steeple, the trail to which starts in Pine Grove Furnace State Park and ends here, in Michaux State Forest.
It may be called South Mountain, but it's the northernmost part of the Blue Ridge physiographic province that runs all the way down to Georgia. Here, where tilted strata of Montalto Member metaquartzite form the heights just southeast of the state park's Laurel Lake, we're only some 13 miles from where this great physiographic province ends.
In addition to being an area of endless geologic interest, South Mountain has played an important role in US history. In the American Civil War, for instance, its presence profoundly affected the movement of both Federal and Confederate armies, and influenced where they met to do battle in such famous locales as Antietam and Gettysburg.
The white Montalto quartzite, a member of the Cambrian Harpers Formation, was originally deposited unconformably atop Neoproterozoic rhyolite. Both units were thrust up to a much higher level and metamorphosed when northwestern Africa collided with what is now the eastern side of North America, during the Alleghenian Orogeny and formation of the supercontinent Pangaea.
One of the most interesting aspects of the quartzite is that it still contains abundant boring tubes of the ichnofossil genus Skolithos even though it was metamorphosed. These tubes were excavated in the sandy Cambrian sea bottom by some marine animal. Part 2 of this series will show one example of these interesting features.
You'll find the other photos and descriptions of this series in my Integrative Natural History of the Blue Ridge Province album.
Integrative Natural History of the Blue Ridge Province, Part 1: High Ground on South Mountain | Michaux State Forest, Pennsylvania, USA
Taken atop Pole Steeple, the trail to which starts in Pine Grove Furnace State Park and ends here, in Michaux State Forest.
It may be called South Mountain, but it's the northernmost part of the Blue Ridge physiographic province that runs all the way down to Georgia. Here, where tilted strata of Montalto Member metaquartzite form the heights just southeast of the state park's Laurel Lake, we're only some 13 miles from where this great physiographic province ends.
In addition to being an area of endless geologic interest, South Mountain has played an important role in US history. In the American Civil War, for instance, its presence profoundly affected the movement of both Federal and Confederate armies, and influenced where they met to do battle in such famous locales as Antietam and Gettysburg.
The white Montalto quartzite, a member of the Cambrian Harpers Formation, was originally deposited unconformably atop Neoproterozoic rhyolite. Both units were thrust up to a much higher level and metamorphosed when northwestern Africa collided with what is now the eastern side of North America, during the Alleghenian Orogeny and formation of the supercontinent Pangaea.
One of the most interesting aspects of the quartzite is that it still contains abundant boring tubes of the ichnofossil genus Skolithos even though it was metamorphosed. These tubes were excavated in the sandy Cambrian sea bottom by some marine animal. Part 2 of this series will show one example of these interesting features.
You'll find the other photos and descriptions of this series in my Integrative Natural History of the Blue Ridge Province album.