Yesterday, we had a joint NOVA-University of Pittsburgh at Johnstown field trip to Shenandoah National Park. It was a great day of examining new rock outcrops and old treasured favorites. UPJ is responsible for one of the only departmental student-centered geology blogs that I am aware of, Mountain Cat Geology. A couple of weeks ago, igneous and metamorphic petrology professor Elli Goecke contacted me about local rock options, and I invited her crew to team up with the NOVA GOL 135 field course to check out Shenandoah. [Geoblogger small world: Elli studyed under Kim Hannula in Vermont!]

Together, the sixteen of us checked out evidence for the two Wilson Cycles recorded in the rocks of Virginia's Blue Ridge province, and had a pleasant time hiking around and enjoying unparalleled fine weather. Unfortunately, November means the days are short, and we had the sun set on us before we got to the final stop (at Signal Knob Overlook). We took a group photo there: see if you can spot who's a NOVA person and who's a UPJ person...


The annotated version, to show who's who:


Thanks for a great day in the field, everyone!

Labels: blogs, blue ridge, field trips, national parks, nova, pennsylvania, shenandoah, virginia

That's a slab of the Shawangunk Formation conglomerate, from eastern Pennsylvania. I collected it a couple of years ago when I drove up to go fossil hunting at the Whaleback, but it wasn't until last year that I slabbed and polished it. (The slab measures 10 cm wide by 27 cm in length.) Then a couple of months to get around to scanning it, and finally a few months more before posting it. Sheesh.

It's a lovely quartz-rich clast-supported conglomerate, a ridge former in the Valley & Ridge province of the Appalachians. Like the Massanutten Formation, it's Silurian in age, and thought to be part of the "molasse" sequence shed off the Taconian mountain belt, first raised during the late Ordovician. It is interpreted as a relatively-high-energy fluvial system deposit; sediments laid down by rivers as the mountains next door were weathered and eroded.

Labels: appalachians, pennsylvania, quartz, sediment, silurian, valley and ridge, weathering

Richard Dawkins is on a speaking tour in promotion of his new book on the evidence for evolution, which I just got yesterday. He's not coming to DC, but the closest speeches he'll be giving are in Charlottesville, at UVA (Oct.16), and then in Philadelphia, at the library (Oct.22).

Labels: evolution, meetings, pennsylvania, virginia

Labels: arizona, art, books, delaware, maine, maps, new jersey, pennsylvania

My student Joel recently went up to Clarion County, Pennsylvania, where he encountered this striking example of a stream contaminated with acid mine drainage (lifeless rust-filled stream at right) merging with an undegraded stream (at left). Wow:

Photograph by Joel Bosch.

Labels: environmental, minerals, mining, pennsylvania, water resources

On Tuesday afternoon, four students and I drove from Annandale, VA, up to Buffalo, NY, for the NE section meeting of the Geological Society of America. On the way, we crossed the Pennsylvanian Appalachians, and pulled over to examine some beautiful redbed exposures on the Pennsylvania Turnpike. I think these are in the Hampshire Formation, but I could easily be wrong about that, considering I've never been here before. Here's a few photos. First, some beautifully rhythmic alternations between sand and mud, now preserved as alternating layers of sandstone and mudstone:

Then, some nice "ball and pillow" structures, as heavy sand sank downward into squishy mud. In places, the mud skooshes upward in "flames":

And lastly and most amazingly (for me), some awesome exposures of flute casts. These are erosional scours into a layer of sediment by a current, which then fills in the scours (called "flutes") with sand, making these flute casts on the underside of the overlying layer of sand:

The flutes "point" upstream, and open up (and shallow) in the downstream direction. More later!

Labels: appalachians, meetings, nova, pennsylvania, primary structures, sediment, teaching

Last week, I put up some pictures of the folded strata at "the Whaleback" outside of Shamokin, Pennsylvania. Today, I'll augment those with some images of the fossils found at that site and at another outcrop of the Llewellyn Formation near St. Clair, Pennsylvania. Here's a fern impression to start with:

Labels: appalachians, fossils, pennsylvania

Outside of Shamokin, Pennsylvania, is a coal strip mine that has had the coal stripped away. Under the coal was a Pennsylvanian (in the time sense of the word) carbonaceous shale (the Llewellyn Formation), which is now preserved in lovely undulating Appalachian folds. Thanks to the removal of the coal, these fold surfaces appear in three dimensions -- a rarity for structural geologists like myself. The area is known as "The Whaleback" because of one anticline (center) with a shape that evokes a surfacing cetacean:

I went to the Whaleback last fall on a fossil-hunting trip with the The Calvert Marine Museum Fossil Club. In today's post, I'll take a look at the structure, and in a later post, I'll show you some photos of the fossils themselves. Here's some of the guys on the trip:

At the north end of the excavation, a cross-sectional view of the absent upper levels is preserved, showing this syncline. It once continued towards the camera's perspective in the air, a downflung fold between the Whaleback anticline and the neighboring anticline which made up the background "wall" in the first photo.
Okay, that's it for today. Tune in soon for the fossiliferous sequel.

Labels: appalachians, concretions, pennsylvania, structure