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 Virginia.
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Friday fold: Tight syncline/anticline pair in Brallier Formation
The Friday fold shows clastic detritus (turbidites or “flysch” from the Acadian Orogeny) crumpled into tight folds due to the later Alleghanian Orogeny.
Eocene dike and sill in Ordovician limestone
A virtual field trip to a quarry in far western Virginia, showing anomalous igneous intrusions (a dike and a sill) of Eocene age cross-cutting early Paleozoic carbonates.
Martinsburg Formation outcrops in Edinburg Gap
A report from the field: new outcrops of Ordovician-aged turbidites featuring geopetal indicators, fossil content, and a structural overprint imparted during Pangaea’s assembly.
Zoophycos trace fossils in Mahantango Formation, Fort Valley
A morning’s field trip yields an outcrop of excellent Zoophycos trace fossils in southern Fort Valley, Virginia.
Mechum River Formation, near Batesville, VA
A quick virtual field trip to the Neoproterozoic glaciogenic sedimentary rocks from the central Virginia Blue Ridge province: Can you feel the chill of Snowball Earth?
Book report
Callan reviews 11 books he’s read in the past 11 months, some having to do with geology, many with the intellectual heritage of scientific insight, a few about history, two biographies, and some about random things.
Pisolites in the Tansil Formation, Carlsbad Caverns, New Mexico
Pisolites are large primary concretions that develop in backreef or lagoonal settings such as the Permian Tansil Formation of New Mexico, into which is cut the enormous hole called Carlsbad Caverns.
Miette Group gritstone showing scours, mudchip rip-ups, cross-bedding, and dropstones
The coarser strata of the Neoproterozoic Miette Group in the Canadian Rockies of Alberta record changing water current strength over time, and maybe an iceberg or two.
Geology of the Acropolis (Athens, Greece)
When visiting Athens, Greece, you are drawn to the Parthenon’s grand architecture atop the hill called the Acropolis. But why is the Acropolis a hill?
Friday fold: a surging rippled whale of Grinnell Formation
The Friday fold is asymmetric, overturned, and chock full of primary sedimentary features. Join us in Glacier National Park’s Mesoproterozoic Belt Supergroup.
The stromatolites of Helen Lake 1: photos
The exquisite stromatolites of Helen Lake, Banff National Park, are presented in photographic and GigaPan renditions. Enjoy unwrapping them as your “Christmas gift” from Callan.
A rock slide and a protalus rampart (?) on the trail to Helen Lake
A hike to Helen Lake, Banff National Park, Alberta, brings your intrepid geoblogger face to face with a fresh landslide and a curious landform parallel to the glacial valley. Is it a pro-talus rampart?
Friday fold: Miette slate, Alberta
The Friday fold returns to Canada, looking at Neoproterozoic slate and quartzite at the southern terminus of the Icefields Parkway. Bonus features include ripple marks, graded beds, cross-bedding, cleavage, and boudinage.
Fluvial geomorphology of Mather Gorge
What hath the Potomac River wrought on the rocks of Mather Gorge? Some interesting shapes to the land surface reveal a fascinating history.
Gypsum casts? You be the judge — UPDATE: Syneresis cracks!
Silurian aged mud cracks feature small lensoidal features: are they casts of ancient gypsum crystals?
Friday folds: ploudin trio from Corridor H
Three folded sandstone slab-blobs will serve as today’s Friday folds. Meet the ploudins!
In search of Santorini’s blueschist, part 1: into the Valley of the Shadow of Ash
While in Santorini, Greece, your humble geoblogger braves a warm afternoon to search the hillsides for evidence of subduction.
Lunar eclipse images from the past 2 hours
A selection of “moon shots” from this morning’s lunar eclipse is presented.
Non-bedding-parallel stylolites in Tonoloway limestones, Corridor H
What can a little squiggle in a rock tell us? Stylolites in West Virginian limestone cut across the bedding plane, implying Alleghanian tectonic stresses.