Structure trip 4: Route 55 redux
When I visited the exposures along newly-minted New Route 55 in West Virginia in March, I was so impressed, I decided to bring my structural geology students there on our trip. Now, after two stops in the Blue Ridge and a late afternoon anticlinorama, we woke, broke camp, and ate some great eggs and sausage (mine were swimming in coffee due to an accident with the French Press, but hey -- it all goes the same place, right Ben?) and set off to the west.
Hanging Rock Anticline roadcut:
Hanging Rock Anticline as viewed from the valley of the Lost River, where Old Route 55 wends and winds:
Ben, Dave, and Joe on the berm (note the thrust fault above their heads):
Plenty of primary structures to be seen here, too, like these trace fossils:
A hand-sample of trace-fossils (Arthrophycus, I think):
...or this beauty:
Small reverse fault with an offset of ~1 meter:
Here's a fossil (??) that I don't understand and cannot identify. I saw four of these out there. Can anyone (Tom, ReBecca?) help me identify this sucker and understand how it formed?
We moved on down the road a bit, to this lovely monocline (Jim & Jay for scale):
John, Karine, & Ryan take a closer look at primary and secondary structures in these strata:
Lovely flute casts:
Plumose structure #1:
Plumose structure #2:
Paleo-river channels incised into these strata (at the time of their deposition):
Reduction "halo" around a carbonaceous plant fragment fossil:
Ripple marks:
More plant fossils (these were the largest I saw):
Lots of carbon films of shredded up plant chunks:
Ball & pillow / flame structures:
Ditto, and note the graded bedding in the upper sandstone layer, too:
Great trip, everyone! Thanks!
Hanging Rock Anticline roadcut:
Hanging Rock Anticline as viewed from the valley of the Lost River, where Old Route 55 wends and winds:
Ben, Dave, and Joe on the berm (note the thrust fault above their heads):
Plenty of primary structures to be seen here, too, like these trace fossils:
A hand-sample of trace-fossils (Arthrophycus, I think):
...or this beauty:
Small reverse fault with an offset of ~1 meter:
Here's a fossil (??) that I don't understand and cannot identify. I saw four of these out there. Can anyone (Tom, ReBecca?) help me identify this sucker and understand how it formed?
We moved on down the road a bit, to this lovely monocline (Jim & Jay for scale):
John, Karine, & Ryan take a closer look at primary and secondary structures in these strata:
Lovely flute casts:
Plumose structure #1:
Plumose structure #2:
Paleo-river channels incised into these strata (at the time of their deposition):
Reduction "halo" around a carbonaceous plant fragment fossil:
Ripple marks:
More plant fossils (these were the largest I saw):
Lots of carbon films of shredded up plant chunks:
Ball & pillow / flame structures:
Ditto, and note the graded bedding in the upper sandstone layer, too:
Great trip, everyone! Thanks!
Labels: field trips, fossils, primary structures, sediment, structure, teaching, valley and ridge, west virginia
4 Comments:
Are you sure those things are fossils and not some type of load structure? If not, could they be oncolites? Oncolites have been described from fairly deep water (>40 m) from the Devonian of Australia, but they still had internal laminations preserved.
Not certain what the blob is: I'll have to think about it.
Kick-ass flute casts, though!
Alton,
No, I'm not 100% certain it's a fossil, but it was always found pointing down from a sandstone layer into an underlying muddy layer, and usually associated with Arthrophycus traces. And the best-preserved ones have a sea-cumuber-like texture on the sides. It's weird...
C
I was going to ask the same as Alton- from the pictures, it looks liek some kind of soft sed deformation- but the association with other fossils and texturing of the sides doesn't fit too well with that idea. My paleozoic paleo knowledge is not too deep, so I'll just stop there.
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