17 April 2017 01:00 in groundwater, sandstone, weathering, west virginia by Callan Bentley
An easter egg on a piece of toast? No, it’s a nice example of Liesegang rings in a slab of sandstone. Explore more in this blog post.
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20 May 2015 14:51 in appalachian plateaus, chemistry, pennsylvanian (carboniferous), sandstone, west virginia by Callan Bentley
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: …
9 January 2013 13:51 in africa, chemistry, joints, minerals, south africa, travel, weathering by Callan Bentley
Callan continues his week-long recounting of his five-day backpacking trip from the Cape of Good Hope to Cape Town, South Africa, along the Hoerikwaggo Trail. Today, we examine the jointing, oxidizing and reducing fluid flow, and the emplacement of ore veins.
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15 July 2011 09:04 in Friday Fold, illinois by Callan Bentley
Today, the Friday fold is a fake! Looks like a nice set of asymmetric antiforms and synforms, right? But it ain’t! It’s naturally wiggly; primary not tectonic. The photo shows nothing more than differential erosion of hematite that was deposited by groundwater in permeable sandstone. It’s Liesegang banding! These hematite blobs are in the sandstone at Giant City State Park, south of Carbondale, Illinois. Several are cylindrical in form, presumably …
11 October 2018 10:11 in Q&A, structure by Callan Bentley
A reader asks about Callan’s source of inspiration, a fitting question given the advent of Earth Science Week, which this year has as its theme “The Earth as Inspiration.” Brace yourself for a tantalizing cavalcade of gorgeous images of patterns in rocks!
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25 April 2018 16:21 in fossils, geomorphology, kentucky, plants, tafoni by Callan Bentley
A visit to a natural sandstone arch (or “bridge” as the locals call it) in eastern Kentucky yields unexpected bonuses, like fossil wood, Liesegang banding, and the honeycomb-like weathering pattern called “tafoni.”
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19 August 2015 12:14 in chemistry, sandstone, west virginia by Callan Bentley
What do a sweaty baseball cap and fractured sandstone have in common? Episodes of absorption of dirty liquids that pile up material such as iron oxide at the soaking front.
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7 January 2013 16:09 in africa, mammals, maps, south africa, tafoni, travel by Callan Bentley
Callan begins a week-long recounting of his five-day backpacking trip from the Cape of Good Hope to Cape Town, South Africa, along the Hoerikwaggo Trail. Today, we examine scenery and logistics of the trail.
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2 February 2012 12:21 in chemistry, shale, valley and ridge, west virginia by Callan Bentley
Rust swirls on shale fragment, new New Route 55, Valley & Ridge province of West Virginia. I’m not sure if I can call this “Liesegang banding,” since it’s just on the joint surface (two-dimensional) rather than permeating the rock in a three-dimensional blob. Anyhow… It’s pretty.
11 January 2012 10:34 in africa, primary structures, quartz, sediment, south africa by Callan Bentley
At the Three Rondavels overlook in the northern Drakensburg Mountains of South Africa, I saw this chunk of quartzite with a peculiar variety of Liesegang banding (iron oxide staining of the rock by groundwater): A short distance away, I found another example: In one key way, I liked this second example better, even though the Liesegang banding wasn’t as well expressed here. The improvement is that it also shows bedding, …