The word on playa dust and links for the newbie -

^Rhino! · Post by **^Rhino!** » Sun May 16, 2010 12:23 am

Bob, Bob, Bob.....I thought you as an engineer would understand.

Shale is a PROBLEM GEOMATERIAL. And cricket has come up with a research problem.

Actually, if you think about it, a playa is a dried lake bed. Fine sediments in lake beds lithify into shales with the addition of heat, pressure, and the chemical changes that geologists call 'diagenesis'. Ever heard of the Green River Formation in Utah and Wyoming? Yeah, the ones they get fossil fish out of? That's lithified lacustrine (lake) sediments.

Snow, you're right. the Nevada Bureau of Mines and Geology website is a real pissant. It's a real pity since they and the Mackay School of Mines at U. Nevada-Reno are damn good. I've run into a few of their geologists periodically at national meetings, like for AIPG and GSA. They even hosted the Industrial Minerals forum a few years back. [Regarding the Industrial Minerals forum......Normally at that forum serious bucks are being spent by the host state to make the visitors at home. I've been to the ones in Missouri and Oklahoma....the one in Maine actually had Maine lobster being served at the no charge banquet that ends the meeting.....in Oklahoma, they were awfully proud of their big ribeye steaks.....Industrial Minerals forum is always good for weight gain in my opinion. I highly recommmend it for geologists.]

Snow · Post by **Snow** » Sun May 16, 2010 8:28 am

You cant call the playa sediments shales anyore than you can call a pile of sand a sandstone, or a shale a slate. Sure MAYBE someday they will become preserved as shales but without the time, pressure and heat there is no Shale about it, they are just alluvium. MAYBE i'd let you call them posssible shale precursors. We don't call hops beer or grapes wine now do we?

I'm a Mackay alum. myself.

bm_cricket · Post by **bm_cricket** » Sun May 16, 2010 9:03 am

Snow wrote:You cant call the playa sediments shales anyore than you can call a pile of sand a sandstone, or a shale a slate. Sure MAYBE someday they will become preserved as shales but without the time, pressure and heat there is no Shale about it, they are just alluvium. MAYBE i'd let you call them posssible shale precursors. We don't call hops beer or grapes wine now do we?

I'm a Mackay alum. myself.

All good points.. but when I see hops and grains all I can think of is what would happen with the addition of water, temperature, yeast, and time. (With the addition of my brewing equipment's help that is)

Bob · Post by **Bob** » Sun May 16, 2010 9:22 am

Andrew Lawson, one of the founders of Earth Sciences at Berkeley, wrote that the Orinda formation in the Berkeley Hills (mostly clay, from an engineering perspective) was "feebly coherent". That could describe a lot of people's playa experience.

Snow wrote:They aren't even really cluing us in on their technology, but we are told we will be recieving some kind of power recievers on the playa, they did NOT want us to get one before hand. I'm intrigued.

Huh, I've never gotten more than a volt or two potential from a playa battery no matter how much I peed on it.

Sail Man · Post by **Sail Man** » Sun May 16, 2010 10:37 am

bm_cricket wrote:
theCryptofishist wrote:
bm_cricket wrote: Geologists aren't the only ones. I've had doctors turn "sprained ankle" into a 8 word, 32 syllable mess.
You should see what they did with my ankles.
Mine too. March 23th I had an FDL/FHL transfer with FDL reconstruction, calcaneous osteotomy, and a hardware extraction from a previous botched surgery. Ain't modern medicine great?!

Ahhhh Crypto, aren't they so cute when they are so young and unaware

^Rhino! · Post by **^Rhino!** » Mon May 17, 2010 8:05 am

Perhaps a better term would be lacustrine (lake) sediments. And you know as well as I how much geologists love to argue terms.

Mackay School of Mines is the best in Nevada, bar none. And Berkeley is a great institution, too, Bob. One of the paleontology folks out there is one of the best in the world.

Snow · Post by **Snow** » Mon May 17, 2010 9:08 am

that is MUCH better

Fire_Moose · Post by **Fire_Moose** » Mon May 17, 2010 9:57 am

Nerd practice is still going on, huh?

Bob · Post by **Bob** » Mon May 17, 2010 10:16 am

Glacial milk is toxic! How many people have to die before the EPA bans erosion and material transport processes?

EmilyD · Post by **EmilyD** » Mon May 17, 2010 10:16 am

Fire_Moose wrote:Nerd practice is still going on, huh?

I'm really enjoying this discussion, guess I'm a geo-nerd too then. I almost minored in Geology, but went for the art degree instead. Is there a geo-camp at burning man? If not, maybe there should be.

^Rhino! · Post by **^Rhino!** » Mon May 17, 2010 11:40 am

"Glacial milk is toxic! How many people have to die before the EPA bans erosion and material transport processes?"

GEEZ, Bob, they already tried! Instead, we now have to fill out the NPDES form. What do you want? A full bore EIA?

Really!

LostinReno · Post by **LostinReno** » Mon May 17, 2010 2:24 pm

EmilyD wrote:
Fire_Moose wrote:Nerd practice is still going on, huh?
I'm really enjoying this discussion, guess I'm a geo-nerd too then. I almost minored in Geology, but went for the art degree instead. Is there a geo-camp at burning man? If not, maybe there should be.

We have Camp Geosmached, but we're primarily a bunch of GPS nerds. We welcome rock nerds...heck we welcome all nerds!

professorzed · Post by **professorzed** » Mon Jun 14, 2010 2:02 pm

On the topic of using vinegar to neutralize the alkalinity of the playa dust.

I remember reading that someone has successfully used [b]soda water[/b] to do this. It has the same acidity as vinegar/ lemon juice, but without the smell.

It makes for a good drink mix too. Scotch and soda, gin and tonic, etc. Quinine is the stuff in the soda water that gives it that 'mediciney' taste, and prevents you from getting malaria in hot, damp, swampy climates.

This is a bit off topic perhaps, but is vinegar popular as a condiment anywhere in the United States? New England perhaps?

I always remember getting funny looks whenever I am in a restaurant in the United States and I add vinegar to chips (french fries), fish, or any other greasy food. Some people will even say that they have [i]never[/i] seen anyone add vinegar to their chips before.

I don't know why it's considered as so peculiar. There is vinegar in ketchup after all. The acid in vinegar helps to break down complex starches (potatoes) so that they are more easily digested by the body.

This is one of the reasons why Apple cider vinegar is recommended for people trying to lose weight. Strangely, it's also in pill form...because some people find the taste of vinegar to be so disgusting.

Post by **AntiM** » Mon Jun 14, 2010 4:16 pm

I like the taste of vinegar. I don't drink it, but I use it all the time. I think I have half a dozen different vinegars in the house at any time.

FaeTora · Post by **FaeTora** » Mon Jun 14, 2010 4:25 pm

I really don't enjoy vinegar. if a recipe calls for it, i'll use it and hope I can't taste it. the realisty is it is the taste that bothers me more than the smell. I'm not huge on condiments, then again I don't eat greasy foods often, don't really eat sanwiches, and I don't eat meat. i'm a non-typical american.

theCryptofishist · Post by **theCryptofishist** » Mon Jun 14, 2010 7:58 pm

professorzed wrote: It makes for a good drink mix too. Scotch and soda, gin and tonic, etc. Quinine is the stuff in the soda water that gives it that 'mediciney' taste, and prevents you from getting malaria in hot, damp, swampy climates.

It is medicine. And it's in Tonic Water, but not Soda Water.

professorzed wrote:This is a bit off topic perhaps, but is vinegar popular as a condiment anywhere in the United States? New England perhaps?

Why New England? Because they are so prim? So English?

I do like vinegar on chips, however.

ygmir · Post by **ygmir** » Mon Jun 14, 2010 8:23 pm

vinegar this, and vinegar that,
I miss Simon
and, his funny cat......

well, the cat part was just to rhyme.......but, I know the jokes he could make......I'm always so hestant to step over "that edge"......

timythy · Post by **timythy** » Thu Aug 12, 2010 6:32 pm

This site says people found 85% of a sample Black Rock Desert dust was below 5 microns.

http://www.pall.com/Aerospace_2858.asp

dewnorth · Post by **dewnorth** » Thu Aug 12, 2010 6:55 pm

To ensure the best possible protection, we first examined dust from the Black Rock Desert, where the WLR attempt is held. This examination, conducted by Pall's Scientific and Laboratory Services, established that approximately 85% of the test sample contained dust particles smaller than five microns.

Do they mean 85% of the test sample was smaller than five microns, or did 85% of the samples contain at least some particles under five microns?

I wonder if they worded it properly to reflect their findings.

Show of hands who has time to contact Pall's Scientific and Laboratory Services for clarification.......I'm too busy panicing about building my shade structure right now.

(Wouldn't that car make it a quick trip across the city? The Man better duck!)

Theres Always One · Post by **Theres Always One** » Thu Aug 12, 2010 11:32 pm

Thanks to power to the rhino! for this thread.

Question: I have a scarf I made of LED's that are attached to wires but the LED leads and parts of the wires are exposed. (I also used silicone caulk to cover some of the exposed areas without knowing how corrosive the silicone caulk is). But do you all think my scarf will survive the playa? At least through my week there? I just want it to survive until I come home so I can make a new (better) one. The exposed LEDs/wires are sealed within a sealed fleece sleeve so it's not like they are directly exposed to the elements. What say you?

gyre · Post by **gyre** » Fri Aug 13, 2010 5:16 pm

I would think so.

Looks good.

darcitananda · Post by **darcitananda** » Mon Aug 16, 2010 7:52 pm

Fascinating thread. And I'm not being sarcastic.

I would like to add that lemon juice is not a safe acid to use on the skin as it can be phototoxic and cause awful chemical burns when the skin is exposed to the sun. If you are planning to use lemon or lime juice make sure you rinse with plain water afterward, or avoid sun exposure.

Ok, back to all the geology geeking out!

Sprockets · Post by **Sprockets** » Fri Nov 05, 2010 11:30 am

Thanks for your analysis Rhino. I have some questions though as I find some of your analysis contradictory. I did my Ph.D. in atmospheric chemistry, specializing in the chemical reactions that mineral dust particle undergo in the atmosphere, and how these affect their cloud nucleation properties. So I just have a passing familiarity with dust mineralogy.

Your attempt to reconstruct the mineralogy composition of playa dust based on the available chemical composition is interesting. However, I am confused with your conclusion that playa dust is alkaline due to the presence of gypsum. Gypsum (CaSO4.2H2O) is not alkaline. Anhydrous calcium sulphate is quite hygroscopic and a strong desiccant. But dessication is not the same as corrosion. In fact, you usually need water to promote corrosion.

Actually if you react calcium carbonate (a base) with sulphuric acid (an acid), you get calcium sulphate (a neutral salt):

CaCO3 + H2SO4 -> CaSO4 + H2O + CO2(g) (the bubbles!)

Calcium sulphate won't react with other acids in an acid-base neutralization reaction.

So if playa dust is alkaline, it must have some carbonates present. Calcite, aragonite, or could some of the Mg be in the form of Dolomite (CaMg(CO3)2)?

Also, plaster of Paris is CaSO4.1/2 H2O.

What you wrote about playa dust sticking to surfaces due to covalent bonds is incorrect. Covalent bonds are very strong and form via electronic interactions at the atomic level. Dust sticking to stuff is due to much weaker electrostatic interactions.

Sorry if I'm being picky, just trying to clarify these issues! :)

Oh, and 5 microns is really big as far as airborne particles go. The smallest particles (not from dust) are just a few nanometers in diameter.

I have a bunch of Black Rock Desert playa dust I collected years ago. I can see about getting an X-Ray diffraction spectrum measured.

Cheers,
Ryan

Bling · Post by **Bling** » Fri Nov 05, 2010 11:33 am

Ryan, can you analyze the Playa dust for respirable crystalline silica? I've been wondering how much of a risk that is--not so much for folks who have just a week of exposure/year, but more so for volunteers who set up or clean up and are out there for weeks...

Sprockets · Post by **Sprockets** » Fri Nov 05, 2010 11:38 am

Bling, are you worried about lung silication? (I forget the proper term)

I don't do that sort of analysis myself, but if I get an xray spectrum measured that should show up. Could also try FT-IR spectroscopy...

One tip is to look at what size of particles any face masks you're using are rated for. Many only trap the supermicron particles. There are lots of submicron dust particles around, and those tend to penetrate much deeper into the lungs.

Bling · Post by **Bling** » Fri Nov 05, 2010 11:40 am

Yes. RCS is a direct carcinogen. I've never seen a good analysis of Playa dust particle size and composition. I'm NOT a geologist--just want to know what type of risk there is.

Sprockets · Post by **Sprockets** » Fri Nov 05, 2010 11:44 am

Well, it seems pretty certain that a large fraction of playa dust is composed of quartz, which is a form of silica...

Bling · Post by **Bling** » Fri Nov 05, 2010 11:47 am

Probably. Then the question is particle size.

Bob · Post by **Bob** » Fri Nov 05, 2010 12:37 pm

An x-ray diffraction breakdown of the clay-sized fraction would be most welcome. The parent rock sources are pretty varied.

^Rhino! · Post by **^Rhino!** » Wed Dec 29, 2010 5:56 pm

"Thanks for your analysis Rhino. I have some questions though as I find some of your analysis contradictory. I did my Ph.D. in atmospheric chemistry, specializing in the chemical reactions that mineral dust particle undergo in the atmosphere, and how these affect their cloud nucleation properties. So I just have a passing familiarity with dust mineralogy."

You're welcome. I apologize for some of the mineralogical shorthand of my thinking, and I'll clarify here.

"Your attempt to reconstruct the mineralogy composition of playa dust based on the available chemical composition is interesting. However, I am confused with your conclusion that playa dust is alkaline due to the presence of gypsum. Gypsum (CaSO4.2H2O) is not alkaline. Anhydrous calcium sulphate is quite hygroscopic and a strong desiccant. But dessication is not the same as corrosion. In fact, you usually need water to promote corrosion."

Exactly. The presence of gypsum (which is also water-soluble, by the way) and calcite together in the dust (I'm holding on to my analysis until I get it published, btw) indicates to me that it's in an arid or semiarid environment. We get gypsum in conjunction with some of the shales here in Missouri (there's one shale that causes concrete floors to heave upwards even underground in the Kansas City area simply because of the humidity) and within a few years, the gypsum has pulled in all the water from the surrounding environment. At that point, given the right geochemical conditions, the sulfate from the gypsum will attack calcite in a self-perpetuating reaction when it forms sulfuric acid.

"Actually if you react calcium carbonate (a base) with sulphuric acid (an acid), you get calcium sulphate (a neutral salt):

CaCO3 + H2SO4 -> CaSO4 + H2O + CO2(g) (the bubbles!)"

And when you dissolve the CaSO4 (anhydrite) in water, you get Calcium ions and sulfate ions. Note that you also included CO2 and H2O in the products of the equation above. CO2 + H2O -> H2CO3 (carbonic acid). This is the first reaction that will eventually dissolve limestone and you get karst.

"Calcium sulphate won't react with other acids in an acid-base neutralization reaction."

True dat.

"So if playa dust is alkaline, it must have some carbonates present. Calcite, aragonite, or could some of the Mg be in the form of Dolomite (CaMg(CO3)2)?"

It's calcite. We got a violent reaction in dilute HCl.

"Also, plaster of Paris is CaSO4.1/2 H2O."

Which is one-half step short of anhydrite, CaSO4.

"What you wrote about playa dust sticking to surfaces due to covalent bonds is incorrect. Covalent bonds are very strong and form via electronic interactions at the atomic level. Dust sticking to stuff is due to much weaker electrostatic interactions."

You mean ionic bonding. I was searching in my mind for the right term, but I'm wrong. Thanks for the correction/clarification.

"Sorry if I'm being picky, just trying to clarify these issues! :)"

You didn't come across as picky, you came across as inquisitive. Thank you.

"Oh, and 5 microns is really big as far as airborne particles go. The smallest particles (not from dust) are just a few nanometers in diameter."

What about the silt-sized fractions in the loess deposits of the US Midwest? They weren't atmospheric dust, they were more ground level-ish silt, transported by the process of saltation, repeatedly striking the ground before taking off again. Just like fine sand.

"I have a bunch of Black Rock Desert playa dust I collected years ago. I can see about getting an X-Ray diffraction spectrum measured."

It would be informative and a good check on what limited data I have so far. I invite it, welcome your involvement, and thank you in advance for any results. Feel free to message me if you wish.

"Cheers,
Ryan[/quote]"

Cheers and kind regards to you, sir.

^Rhino!

The word on playa dust and links for the newbie -

Shale

Glacial milk is toxic........

Soda water

Re: Soda water

Mineralogy

Re: Mineralogy