stylolites

McKittrick Canyon, Guadalupe Mountains National Park, Texas

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While in West Texas over spring break, the “Border to Beltway” students took a hike up McKittrick Canyon, in Guadalupe Mountains National Park. This is part of the famed Permian reef complex, the deep reservoir of Texas’s rich endowment of oil. Here, the reef comes to the surface. In fact, it pokes up a good … Read more

Fusulinids and stylolites, Hueco Formation

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My colleague Joshua Villalobos shared this image with me the other day – it’s a thin section of fusulinid-bearing limestone of the (Permian aged) Hueco Formation, from the Tom Mays Unit of Franklin Mountains State Park, Texas. Click to enlarge Note the scale bar at lower left. The big fusulinid in the middle is 3mm … Read more

Stylolite from the Helderberg Group, exposed on Corridor H

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While out on the Corridor H field trip last week before the heavy snow, I found this squeal-inducingly-lovely example of a stylolite in Helderberg Group limestones (Devonian passive margin carbonates): The stylolite is a pressure-solution surface, made especially apparent in this example because of the starkly different grain sizes and colors on either side of … Read more

Strained stylolites at Foamhenge

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One thing that’s 100% worth doing if you find yourself visiting Natural Bridge, Virginia, is to pop in for a visit at Foamhenge, an art installation a few miles away. Foamhenge is a full-scale replica of Stonehenge, made of styrofoam (covered in gray latex paint). It’s a few years old now, so it’s begun to … Read more

Friday fold: the case of the strangely stout stylolites

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Today, we return to my field trip from last week, for a look at an odd outcrop of the Ordovician-aged Edinburg Formation: Note the car key with green lanyard, to provide a sense of scale. It’s folded, as the yellow bedding traces show in this annotated version: But what really caught my eye about this … Read more

Strained stylolites in Elkton East

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Whoa – look at all that GREEN. You can tell this Virginia picture wasn’t taken recently. In fact, it’s another image from the field review I participated in for the Elkton East quadrangle back in May of last year. Somehow I start blogging these things, but run out of steam (or really more accurately: I … Read more

What those geologists were looking at

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Yesterday, I showed you a scene of geologists (including me) clustered around some (presumably interesting) outcrop. I asked what you thought we might be looking at. Howard Allen, a denizen of this part of the globe, immediately identified the scene as that of the downstream end of the Athabasca Glacier. Several people guessed that we … Read more