Day #59 Outcrop: Potash Evaporation Ponds

As many times as I’ve passed the Bonneville Salt Flats, it seems I still don’t have a digital photo of them. So, to continue the evaporative theme for the weekend, today’s “outcrop” is the potash evaporation ponds, near Potash, Utah. This was always a fun stop on the FHSU Geology Summer Field Camp. We would first catch a glimpse of the distinctive sky blue ponds from a stop at Dead Horse Point State Park, near Moab, Utah (below).

Potash Evaporation Ponds from Dead Horse Point, Utah

The following day we’d make the drive along the Colorado River to Potash, Utah, and, after getting permission at the Intrepid Potash office, go in to view the ponds up close (below).

Potash Evaporation Ponds

The evaporation ponds are part of a brine well, solution mining operation aimed at recovering potash for fertilizer. Hot water is injected into wells that bottom in the Paradox basin evaporite beds, hundreds of feet down. Halite and sylvite are dissolved by the hot water and the resulting brine is pumped to the surface for evaporation. Blue food coloring is added to speed the evaporation process.

Blue Brine and Potash Salts

Tomorrow’s deskcrop will explore one of the spectacular accidental by-products of this evaporation operation.

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Day #58 Outcrop: Devils Golf Course

In keeping with the salty weekend theme I thought we’d do a round of geology at the Devil’s Golf Course. From the floor of Death Valley one can see Telescope Peak rising in the distance, nearly two miles of vertical relief from the salt pan in the foreground to the peak in the distance. The salt pan here is weathered into one of the most evil and unplayable lies a golfer could imagine. I used to have a hand sample of this surface, but it seems to have dissolved into the mists of time.

Devils Golf Course & Telescope Peak

Close Up of the Salt

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Day #57 Deskcrop: Halite

Tomorrow the Sternberg Geosciences Club will be taking a field trip to the Kansas Underground Salt Mine and the Kansas Cosmosphere, in Hutchinson, Kansas. Since I don’t have any lunar deskcrops, I guess I’ll just post this photo of a piece of layered salt deposits that I got at the mine a couple of years back. Unfortunately this photograph doesn’t really give you a taste of halite’s two most distinctive physical porperties: it’s cubic cleavage and… what was that other one now?


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Day #56 Deskcrop: Bishop Tuff

Continuing the igneous textures theme of the week, today’s deskcrop is a piece of the Bishop Tuff and it displays a very nice pyroclastic texture. This sample is from near the top of the service road that descends to the bottom of Owens Gorge, and as such, is relatively high in the stratigraphic section of the extrusive volcanic products of the eruption that formed Long Valley Caldera 760,000 years ago. You’ll note that pumice fragments are still relatively undeformed at this stratigraphic level, yet the ash is consolidated enough to make this something that I can honestly call a rock. Future deskcrops from this locality will illustrate the increasing deformation of the more welded samples of the Bishop Tuff from lower stratigraphic levels.

Bishop Tuff

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Day #55 Deskcrop: Glomeroporphyritic Basalt

Today’s deskcrop features a rather uncommon and distinctive glomeroporphyritic texture. It appears that the plagioclase phenocrysts in this rock nucleated at a small number of sites and grew into the surrounding magma in a radial pattern. Perhaps it should come as no surprise that the common name for rocks with this texture is “Daisy Stone”. This sample is a Keweenawan-aged basalt from the Algoma region of Ontario, though I’m intentionally putting its placemark in Lake Superior to protect the specific locality.

Glomeroporphyritic Basalt

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Day #53 Deskcrop: Gabbronorite

What do you call an equigranular, phaneritic rock made of plagioclase, orthopyroxene, and clinopyroxene? Well, if they’re in roughly equal proportions like the rock below the technical term is gabbronorite. This deskcrop comes from along the Benbow Mine Road in the Stillwater Intrusion of Montana. It’s not the first, and it certainly won’t be the last deskcrop you’ll see from the Stillwater Intrusion.


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Where on (Google) Earth #188?

Dan was kind enough to post a WoGE near the Somali coast last week without invoking the Schott Rule, so I got a chance to play once again and I didn’t waste any time in recognizing that distinctive low-latitude north facing escarpment.

For those of you who may be unfamiliar with WoGE (who dat?), the object is to search Google Earth until you find the tract of land pictured below. Once you’ve found it, identify its latitude and longitude in the comments to this post and do what you can to describe the geological significance of this area or the landform in question. The winner (first person to post the correct location and geology) will have the honor of hosting the next WoGE competition on their own Geoblog. If you haven’t won (recently) or have just been thinking about starting your own geology blog it’s a great chance to win a little exposure among your colleagues and the bragging rights that go with that. If you’re getting bogged down or just want to take a break from searching, consider taking a tour of past WoGE localities – the list is getting quite impressive. And if you’re still looking for more of this Google Earth geo-goodness have a look at the new Pathological Geomorphology blog which was inspired by WoGE.

I’ll won’t invoke the Schott Rule this time, even though I think it might be easy to recognize the geologic process (if not the specific locality). Just find it, baby!

[Update 3/1/10: Hint – this WoGE locality is in a country that is host to three previous WoGE localities.]

Where on (Google) Earth #188.

Happy hunting!

Day #52 Outcrop: Shale-Coal-Sandstone Stratigraphy

Back to a traditionally defined outcrop, today – well, if you consider a roadcut an outcrop. Exposure, of course, would be a better blanket term for all of these, but it doesn’t rhyme with Deskcrop, so I’ve elected to use the term Outcrop rather loosely in this series.

Anyhow, today’s exposure is a roadcut along Tennessee Highway 8 on the sinuous descent from the Cumberland Plateau, known locally as Fredonia Mountain, into the Sequatchie Valley at Dunlap, TN. There are many excellent exposures of Mississippian and Pennsylvanian foreland basin sedimentary rocks deposited as the Appalachian Mountains were growing to the southeast. The sequence exposed here includes black shales, overlain by a seam of bituminous coal, and capped by a package of fluvially deposited sandstones.

There’s also a nice little rockfall in the foreground – just a little reminder to be cautious when approaching rock faces.

Shale-Coal-Sandstone Stratigraphy

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Day #51 Outcrop: Nisqually Glacier

I sense my geotweeps have a yearning to see a glacier, and it’s my pleasure to do what I can to oblige. The image below was shot back in the summer of 2003 when I first made my acquaintance with Mount Rainier National Park. I visited again this past summer and made a GigaPan from the same spot, but the light was not really optimal.

Nisqually Glacier

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[@cbdawson says: “We need a blog of geo vacation destinations w/associated tips & resources!” Hmmm… I wonder where one could find a blog like that…You’re lookin at it, Cian!]