The latest addition of the Geology departmental field trip rolled out of Williamsburg last Friday and then floated down the James River on Saturday. The weather in the Mid-Atlantic region was iffy. A stalled frontal system bolstered an on-shore flow of moist air, but a spot of rain here and there did not deter the W&M geologists.
Part of the W&M Geology flotilla adrift on the James River.
The Geology departmental trip happens every semester and attracts an array of participants including students in their first geology course as well as junior and senior Geology majors seasoned from past trips. Our flotilla was composed of 20 canoes paddled by 35 students and a crew of 4 faculty.
We floated a 13-kilometer stretch of the James River between Howardsville and Hatton that exposes a tapestry of geological delights including: Precambrian metamorphic rocks, Triassic sedimentary rocks, and Jurassic igneous rocks. We got in the river (literally) to consider the processes at work sculpting the James River’s channel and its floodplain. We measured the cation content of the water and determined that the James River was quietly moving a considerable dissolved load downstream.
Simplified geologic map of the James River between Howardsville and Hatton, central Virginia.
The rapids, that occur where the river crosses erosion-resistant diabase dikes, got our heart racing and in some cases got us wet!
A serious crew of W&M geologists ponder the Triassic bedrock exposed at the river’s edge.
A standup lunch in mid-river.
Lunch was a stand-up affair on a small mid-river cobble bar that is exposed above water only during low flow conditions on the James River. Interestingly, the vast majority of the cobbles were not from local sources, rather these durable clasts had been transported some 100 to 150 kilometers downstream from their bedrock source on the western flank of the Blue Ridge Mountains.
As it turned out, more rain fell in Williamsburg on Saturday than on our James River excursion. By early afternoon the sun was taking back its rightful place in the sky – all things considered it was a fine day to be outside and floating free.
Blue sky and sunshine take over on the Geology departmental field trip.
As I’ve written in past posts these departmental field trips are distinctive as they bring together students and faculty for adventures mixed with a dash of learning that cannot be replicated on campus. Our next departmental field trip is set for the spring semester; the Geology seniors will be in charge and will be showcasing their research discoveries in the field.
The freaks come out at night. Geology students sending mixed messages at our riverside camp (courtesy of Ben Zhang).