Geobulletin alpha

Long-term simulation of green infrastructure effects at a catchment-scale 

The Watershed Hydrology Lab will be represented at the CUAHSI Biennial Symposium in July in West Virginia. Pedro Avellaneda and Laura Sugano have been awarded travel grants to present their research. Here’s Pedro’s abstract: Long-term simulation of green infrastructure effects at a catchment-scale Pedro M. Avellaneda1, Anne J. Jefferson2, Jennifer

3D models to spin and twist 

More 3D models: digital facsimiles of real rock samples. Check them out and explore! Clinker from the Powder River Basin, Wyoming: Ripple marks from the Rose Hill Formation, West Virginia: Meta-komatiite from the Red Lake Greenstone Belt, northern Ontario,

Favosites conicus coral from the Bois D'Arc formation of Oklahoma 

Favosites conicus is perhaps the easiest coral to ID from the Bois d'Arc formation. It's typically a small colony that looks like a gumdrop or beehive.  The base of the coral colony is flat with a wrinkled epitheca that is indicative of the colony growing on a semisolid substrate. The rest of the colony forms a conical mound composed of interlocking hexagonal cells of varying size. I have not found many that are greater than an inch or two in diameter or height which likely indicates there [...]

Five new GIGAmacro images 

Here are a few new images I’ve been working on with my home-based Magnify2 imaging system from GIGAmacro. Strophomenid brachiopods from Mississippian Mauch Chunk Formation, West Virginia: Link Boninite from New Caledonia: Link Lepidodendron scale-tree bark from Poland: Link Potassium feldspar crystal, from a pegmatite: Link Catoctin Formation greenstone from a feeder dike east of Linden, Virginia: Link Enjoy exploring them for

Another trio of 3D models 

Here are three more of my Photoscan-generated, Sketchfab-hosted 3D models of rock samples: Mud cracks in Tonoloway Formation tidal flat carbonates, Corridor H, West Virginia: Diorite from the eastern Sierra Nevada of California: Vein cross-cutting foliated & lineated gneiss, Blue Ridge basement complex,

Friday fold: Harpers Ferry 

The geology east of Harpers Ferry, West Virginia, is cool. It’s Blue Ridge rocks, from basement to the cover sequence, tilted to the west and broken and repeated by the Short Hill Fault. Here’s a look at a detail of the Geology of the Harpers Ferry quadrangle by Southworth and Brezinski (1996). So there’s a fault! Good – but the title of this post isn’t “Friday fault” – Where’s the

Some Cool Weather Images 

The lake effect snow machine turned on yesterday as winter finally arrived in the Northeast U.S. There is even snow over the mountains of West Virginia and Virginia as well. Notice the low stratocumulus clouds offshore, which develop when cold dry air moves over the warmer waters of the Atlantic. I forecast here on the Delmarva Peninsula, and I can tell you that forecasting what that cloud deck will do

Corridor H virtual field experience 

My Historical Geology class was in for a new experience for the semester’s capstone field trip. Before we headed out into the field (to the exceptional roadcuts along Corridor H in Grant and Hardy Counties, West Virginia), we had them examine all the outcrops virtually, in the comfort of the classroom, using digital imagery. I say “we” because this initiative was a collaboration with my colleague Alan Pitts, who developed

Cool fossils from the Clearville member of the Mahantango Formation 

On Saturday, I took my historical geology class on their field trip out to Corridor H, West Virginia. We made a stop at the Mahantango Formation outcrop exposed on the eastbound exit ramp near Baker, and poked around there for fossils. These Devonian-aged siltstones are chock full of invertebrates including rugose corals, crinoids, articulate brachiopods, and even trilobites. Here are two of the best fossils we encountered there: A trilobite

Bedding/cleavage GigaPans at Harpers Ferry, WV 

I’ve been thinking lately about Harpers Ferry, the spot where West Virginia, Virginia, and Maryland meet, at the confluence of the Potomac River and the Shenandoah River. I’ve noted small outcrops of its overturned beddding here previously, and also described a book I read about the man who made the place infamous: John Brown. I went out there again last week with my NOVA colleague Beth Doyle, and we explored

New GigaPans from Team M.A.G.I.C. 

Hampshire Formation outcrops on Corridor H, West Virginia: link (Marissa Dudek) link (Callan Bentley) Faults in the Tonoloway Formation, Corridor H, West Virginia: link (Marissa Dudek) Conococheague Formation, showing stromatolites and cross-bedding: link (Callan Bentley) link (Jeffrey Rollins) Tiny folds and faults, from a sample I collected somewhere, sometime… oh well, it’s cool regardless: link (Robin Rohrback-Schiavone) Fern fossil in Llewellyn Formation, St. Clair, [...]

Mystery structure: please help identify / interpret 

I have a mystery for you today: These are samples of Tonoloway Formation carbonate (not sure if it’s limestone or dolostone in retrospect), with bedding more or less horizontal in these images, and a few petite stylolites running orthogonal to that. The top sample has a gentle fold 2/5ths of the way across. All of the samples are from the same site in West Virginia, along Corridor H. I’m wondering

Paleoslump features and fluvial incision in the Conemaugh Group, West Virginia 

The answer to this week's geological interpretation contest is revealed, sort of. Annotations, GigaPans, and outcrop detail photos reveal the story of equatorial fluvial incision and ancient slumping during the Carboniferous ice

Ripple marks and trace fossils in the Rose Hill Formation 

An outcrop of Silurian-aged Rose Hill Formation in West Virginia reveals excellent examples of ripple marks and trace

Millboro Formation shale in outcrop and in hand sample 

Another site from the GMU sedimentology field trip in April: An outcrop on Route 33 in Brandywine, West Virginia, showing the Millboro Formation. It’s mostly shale, with some intriguing sandstones, too. There are fossils and diagenetic carbonate nodules (concretions). Here’s the outcrop, the largest GigaPan I’ve taken so far (7.9 billion pixels): link The shale itself looks… like shale. It’s fine-grained, and dark (high carbon content, suggesting low oxygen levels [...]

Soft sediment deformation in sandstone and shale, Bolt Mountain 

Two nice new examples of soft sediment deformation structures in Pennsylvanian-aged clastic sedimentary rocks from West

Liesegang banding in Pennsylvanian sandstones, Bolt Mountain, West Virginia 

While out at the eastern section of NAGT’s annual meeting last weekend in West Virginia, I participated in a field trip to look at the stratigraphy of the Bolt Mountain section of Pottsville Group strata. One thing that was particularly eye-catching about the sandstones we saw was that many of them had been stained by rusty groundwater, producing the lovely stripey pattern known as Liesegang banding. Here are five examples:

Driving Through the Most Dangerous Plate Boundary in the World: The Sea Floor that Became the Greatest Agricultural Region on Earth 

Welcome to one of the strangest places on the planet! It's the size of West Virginia, but flatter than the Mississippi River Valley. It was once America's Serengeti, but 95% of the original landscape has been altered. It originated as the bottom of a sea, but now grows most of the nation's produce, and practically all of the nation's walnuts, almonds, and pistachios. It has been a major

Spheroidal weathering in sandstone 

Here’s a nice example of spheroidal weathering in a sandstone, developed using orthogonal jointing and bedding: This is one of many sites I visited Saturday near Bolt, West Virginia, on a field trip with NAGT’s Eastern

Early Paleozoic fossils in Nealmont Formation, Germany Valley, West Virginia 

Looking at Ordovician carbonates in Germany Valley, West Virginia, a few weeks ago on Rick Diecchio’s GMU sedimentology and stratigraphy course field trip: Lots and lots of brachiopods… Crinoid columnals mized with brachiopods: A set of coarsely-infilled trace fossils: Crinoid stem: Nice strophomenid brachiopod: Bryozoan?