I collected only a single rock on my summer travels in France and Italy. (Those of you who know me will realize how extraordinary this low number is!) It’s a flow-banded rhyolite from Vulcano, in the Aeolian Islands north of Sicily a few weeks ago. It contains porphyritic vesicular basalt xenoliths. I featured a similar … Read more
The Friday fold visits the Apennine Range of central Italy.
It’s Friday. Let’s find a historic sort of Friday fold in the ruins of Herculaneum, Naples, Italy.
I was in southern France last week, exploring an awesome suite of caves cut into the Causses limestone plateau. My family and I took an afternoon to paddle a canoe down 5 kilometers of the Célé River. While floating along, we spied a gentle, open fold in the limestone layers that crop out along the … Read more
I spent last weekend at the National Association of Geoscience Teachers’ Eastern Section meeting, based out of the Community College of Baltimore County in Catonsville, Maryland. One of the two field trips I took headed out to the western Piedmont, Blue Ridge and Valley & Ridge provinces of western Maryland. On that trip, we took … Read more
Check this out: is it a fold? Annotated to show the 3D expression of the ‘bed’ (left) and cross-sectional view (right): Here’s a 3D model of the outcrop to better convey its shape: This is in the same sandstone unit I blogged about on Tuesday with the apparent soft-sediment deformation. This could be another example … Read more
I have some questions for you. You answers determine whether you’re ready to begin talking about climate policy. Do you believe that carbon atoms exist? Do you believe that carbon can bond to oxygen? Do you believe that the bonding of carbon to oxygen is an exothermic reaction? Do you believe that exothermic reactions make … Read more
Can soft sediment deformation “loading structures” (ball & pillow) occur when the two strata are identical in composition? Grok on these field photos and chime in with your best hypothesis.
I’ve been busy making 3D models lately. Here are three ones united by a theme of being sand that was deposited relative to mud. In one case we have scouring to make flutes, in another case we have have localized sagging to make “ball & pillow” structures, and in the third case we have an … Read more
Ahhhh, a raw Scottish coast. …Let’s go there. There’s sedimentology to be learned here, and coastal geomorphology to be ogled. This is Yesnaby, on the west side of Orkney. The rocks there are part of “the Old Red Sandstone,” a neat package of Devonian strata, flavored here and there with an igneous dike, a fault, … Read more
In the library the other day, this book’s title caught my eye. I grabbed it and readily consumed it over the past week. It’s a guide to exercising our best critical thinking skills during a time when our attention is awash in claims both vital and derivative, important and erroneous. How do we tell truth … Read more
It’s Friday. We return to Italy’s Macigno Formation for a fold, courtesy of blog reader Samuele Papeschi.
Deep in the Archean, things suddenly got violent in the deep water of the Mapepe Formation’s oceanic setting. What was a quiet precipitation of chert suddenly was torn apart and tumbled downslope. Was an earthquake to blame? A bolide impact? This is the result.
I’ve just finished an excellent book about religion. It’s a survey of major world religions by Huston Smith, titled straightforwardly The World’s Religions. I find religion to be fascinating. It’s a distinct human phenomenon that provides structure and meaning to so many people’s lives, and yet seems entirely superfluous to my own life. That discrepancy … Read more
Journey to the Silurian period in what is today the Valley & Ridge province of eastern West Virginia to see some exquisite sedimentary rocks that represent deposition in a very arid, very shallow setting.
There’s a section of my favorite road, the lovely nowhere-to-nowhere Corridor H, that seems to be having some issues with slumping. I noted this in November of 2015, and I return to the topic today. Here’s a look at the slope, with old drainage “French drains” installed, and a fresh scarp transecting it just the … Read more
I’m preparing for some time in Italy this summer, and picked up a couple of books to bring me up to speed geologically. The first is a geological guide for Rome. It’s structured around the archetypal “seven hills” of Rome, but the story is simpler in many regards than some other seven-hilled European capitals I … Read more
The Foreknobs Formation is a Devonian unit in the Valley & Ridge province of the Mid-Atlantic Region. It was deposited in relatively shallow near-shore conditions during the Acadian Orogeny. On a field trip to Corridor H, a new highway transecting the West Virginian Valley & Ridge province on Monday, I stopped to document a couple … Read more
It’s Friday, the end of the workweek, but also the beginning of the celebration of folded rocks. Examine a particularly sinuous example from the buckled Cambrian limestones of Canada’s Kootenay National Park.
Clarence King was a legend. He led one of the four great surveys of the American west (along with Wheeler, Powell, and Hayden) and eventually convinced Congress to establish One Survey To Rule Them All, an institution that ended up being called the United States Geological Survey. King was its first director, but he didn’t … Read more