Sideling Hill, Maryland
Saturday morning, 6am: I roll out of bed and check the weather. Storms forecast for Hancock, Maryland, where I'm due to be leading a field trip that day. Hmmm. But based on the radar animation, it looks like they're going to hit hard from 10-11am or so, and then ease off for a bit before hitting hard again later in the day.
6:15am: Making coffee, with Lola the cat underfoot. I check the weather again, and convince myself that the timing of the rain will work for our trip's timetable. I decide to go for it.
7:00am: I call Dale Shelton (of the Maryland Geologic Survey) at home and confirm that it's okay if we go out on the outcrop if it's merely wet, but we can't go out if it's actively raining.
7:15am: I e-mail the students, confirming that the trip is a 'go.'
8:15am: "Bye, Lola!" I leave DC and drive out to Annandale. Once on campus, I gather up a few items (first aid kit, whiteboard, topographic maps), and then go out to the parking lot where students are gathering.
9:00am: We depart campus and head northwest.
9:45am: We leave the Piedmont and cross into the Blue Ridge province.
10:03am: We leave the Blue Ridge province and cross into the Valley and Ridge province (though there are a number of Marylanders who persist in calling it the "Ridge and Valley").
10:15am: The rain hits, hard. Windshield wipers on. Behind the wheel, I grimace. Hope it passes...
10:56am: We pull in to the Sideling Hill Visitor Center. Other cars containing other students are there already. We meet up and head indoors.
Sideling Hill is a massive roadcut in western Maryland. If you've ever seen it, you'd remember it. I won't go into all the geological details here, because (due to the rain) we didn't see them all. But if you're interested, you can read in more detail about Sideling Hill on my website. Long story short: We've got some early Mississippian strata here, derived from the weathering of the Acadian highlands to the east, deposited at the edge of the Kaskaskia epeiric sea. Then they were folded up during Alleghenian mountain-building.
12:00pm: After reviewing some of the salient details inside the Visitors Center where it was warm and dry, we ventured out into the rain and wind. Fortunately, a pedestrian walkway over the highway gave us a decent vantage:
Even from this limited vantage, we are able to observe and interpret some interesting features. For instance, check out the differential weathering of the shale vs. sandstone layers here on the eastern side of the outcrop. We likened this to other examples of differential weathering, like at Monument Valley, Arizona.
We also got a good view of what an oxbow lake looks like when viewed in cross-section. Note how this paleo-channel cuts into the layers beneath it, and is filled with a plug of dark shale, indicating low-energy, low-oxygen conditions.
2:00pm: After giving up on our chances to get out on the first berm of the outcrop, we depart the Sideling Hill Visitor Center, but pull over a short distance down the road to examine the diamictite on the western side of the roadcut. In drizzle, and shouting over the traffic, we discuss the multiple origins of diamictites:
2:10pm: On the road again, headed for our second destination, the Paw Paw Bends...
(More on that tomorrow)
All photos by Nicole LaDue, NSF. Thanks, Nicole!
6:15am: Making coffee, with Lola the cat underfoot. I check the weather again, and convince myself that the timing of the rain will work for our trip's timetable. I decide to go for it.
7:00am: I call Dale Shelton (of the Maryland Geologic Survey) at home and confirm that it's okay if we go out on the outcrop if it's merely wet, but we can't go out if it's actively raining.
7:15am: I e-mail the students, confirming that the trip is a 'go.'
8:15am: "Bye, Lola!" I leave DC and drive out to Annandale. Once on campus, I gather up a few items (first aid kit, whiteboard, topographic maps), and then go out to the parking lot where students are gathering.
9:00am: We depart campus and head northwest.
9:45am: We leave the Piedmont and cross into the Blue Ridge province.
10:03am: We leave the Blue Ridge province and cross into the Valley and Ridge province (though there are a number of Marylanders who persist in calling it the "Ridge and Valley").
10:15am: The rain hits, hard. Windshield wipers on. Behind the wheel, I grimace. Hope it passes...
10:56am: We pull in to the Sideling Hill Visitor Center. Other cars containing other students are there already. We meet up and head indoors.
Sideling Hill is a massive roadcut in western Maryland. If you've ever seen it, you'd remember it. I won't go into all the geological details here, because (due to the rain) we didn't see them all. But if you're interested, you can read in more detail about Sideling Hill on my website. Long story short: We've got some early Mississippian strata here, derived from the weathering of the Acadian highlands to the east, deposited at the edge of the Kaskaskia epeiric sea. Then they were folded up during Alleghenian mountain-building.
12:00pm: After reviewing some of the salient details inside the Visitors Center where it was warm and dry, we ventured out into the rain and wind. Fortunately, a pedestrian walkway over the highway gave us a decent vantage:
Even from this limited vantage, we are able to observe and interpret some interesting features. For instance, check out the differential weathering of the shale vs. sandstone layers here on the eastern side of the outcrop. We likened this to other examples of differential weathering, like at Monument Valley, Arizona.
We also got a good view of what an oxbow lake looks like when viewed in cross-section. Note how this paleo-channel cuts into the layers beneath it, and is filled with a plug of dark shale, indicating low-energy, low-oxygen conditions.
2:00pm: After giving up on our chances to get out on the first berm of the outcrop, we depart the Sideling Hill Visitor Center, but pull over a short distance down the road to examine the diamictite on the western side of the roadcut. In drizzle, and shouting over the traffic, we discuss the multiple origins of diamictites:
2:10pm: On the road again, headed for our second destination, the Paw Paw Bends...
(More on that tomorrow)
All photos by Nicole LaDue, NSF. Thanks, Nicole!
Labels: field trips, maryland, stratigraphy, structure, valley and ridge
0 Comments:
Post a Comment
<< Home