You are browsing the archive for basalt.
17 May 2016
I’m in Idaho for the Rocky Mountain section meeting of the Geological Society of America. Yesterday, I was delighted to tour around in eastern Washington’s Channeled Scablands with my colleague Bill Richards (North Idaho College). I took a lot of photos, but here are two to start – lovely examples of “onion skin” style weathering in fractured basalt, producing “kernstones” of increasingly spherical shape: This is a particularly well expressed …
24 March 2016
Pahoehoe “ropes” on a basalt, sample site unknown: Archean gneiss from the Gallatin Range of Montana: Tafoni in Malmesbury Group turbidites, South Africa:
17 March 2016
Our local NSF geoscience education guru, Jill Karsten, is retiring. She and her husband, Rodey Batiza, are packing up their lives and moving back home, vacating the Beltway for good. This might be viewed as a shame as far as geoscience education funding is concerned: Jill has made her mark acting as an advocate of diversifying the geoscience workforce. I hope they get someone similarly awesome to replace her at …
27 June 2013
At Morton Pass, where highway 34 crosses the crest of the Laramie Range, you can see a nice set of (younger) mafic dikes cutting (older) granite/gneiss basement complex. The pink stuff is Archean; the black stuff is Paleoproterozoic; around 2 billion years old. Click to enlarge I got to check out this outcrop on Tuesday with colleagues from the University of Missouri and the University of Wyoming. Deformation in the …
24 April 2013
Another new insight from last week’s visit to the Outdoor Lab was that they have several fine examples of native copper found in float of the Catoctin Formation on their property. Here are a few examples: Classic examples – a bit of malachite in there too, it looks like. I wasn’t totally shocked when I saw these items, since just a month or two ago, I was shown a similar …
17 April 2013
Callan and his colleague Jay Kaufman (University of Maryland) go to extraordinary lengths to document an intriguing block of rock in northern Virginia’s Blue Ridge province. Great images and a lot of fun result – but what do these rocks tell us?
16 April 2013
Join Callan for a look at submarine volcanism and later deformation near Ely, Minnesota. Archean tectonics fluffed these pillows up and squashed them down again.
23 May 2012
A few shots from Fossil Falls, in the southern Owens Valley, California… This is the now-dry river bed of the Owens River. There’s abundant evidence of water-induced erosion (potholes, polishing, etc.), but nary a drop of water to be seen – Though this particular portion of the Owens River drainage dried up in the Pleistocene, it parallels the more recent history of the valley’s water resources, which are now being …
3 May 2012
Today, for your viewing pleasure, I offer you: A series of big honkin’ gas pockets in a 615 ka basaltic lava flow in the Owens Valley of California. This same lava flow has been featured here before, since it imparted a lovely contact metamorphism to the alluvial fan over which it erupted. These things are weird – they’re all about the same size and the same shape (and the same …
1 May 2012
Have you ever seen Archean pillow basalts? How about Archean pillow basalts that have grown much taller through vertical extrusion along a ductile shear zone? Come to the southern Superior Craton to see more!