"Polonium Halos" in Granite

As often happens we get visitors to the Beagle that like to try out their knowledge on us "sciencey" types. A gentleman was looking at Polly in our front window this afternoon. When I told him it was a nearly complete fossil of an adult Psittacosaurus that was 125 million years old, he replied, "you don't really believe that do you?" I allowed as to the fact that I neither discovered the fossil nor dated the fossil itself, but was confident that it had been properly dated most likely based on several factors. He than said, "how do you explain the fact that granite contains polonium, since polonium has a half-life of only a few seconds?" I replied that I didn't have to explain it, but I did tell him that polonium has isotopes that range in weight from 194 to 218 and the natural isotopes have half-lives ranging from 0.145 seconds to 102 years.

After he left I did some data mining on-line and found a short article that is spot on point:

"Creationist Robert Gentry has argued that ring-shaped discoloration (halos) in primordial granite rocks are the result of damage from alpha-particle emission by radioactive isotopes of the element polonium (Po). Since radiogenic polonium has a very short half-life (usually measured in fractions of a second), Gentry argues that, if granite takes thousands to millions of years to form as mainstream geology believes, any polonium originally present would have decayed away long before the granite could have formed and could not have produced these (halos). Therefore, he feels that their existence is evidence for an instantaneous and recent creation of these granite rocks, and by extension the Earth. The following articles point out the flaws in Gentry's argument.
"Polonium Haloes (sic)" Refuted
Professional geologist Tom Bailleul takes a second look at Gentry's claimed polonium (halos), arguing that there is no good evidence they are the result of polonium decay as opposed to any other radioactive isotope, or even that they are caused by radioactivity at all. Gentry is taken to task for selective use of evidence, faulty experiment design, mistakes in geology and physics, and unscientific principles of investigation and argument style.
Evolution's Tiny Violences: The Po-Halo Mystery
Amateur scientist John Brawley investigated Gentry's claims directly by studying local rock samples, and concluded that there is no good evidence that these "polonium" (halos are actually produced by polonium at all, as opposed to longer-lived radionuclides such as radon or uranium."

This was taken from: http://www.talkorigins.org/faqs/po-halos/.

Participate in Midwest Precipitation Measurements

We are on a weekly email blast from Earth Gauge which keeps us updated on the global climate change situation. The following item arrived today and I thought many of you would find it interesting and would want to participate:

Parkville, MO
Link: http://www.earthgauge.net/2010/march-madness-2

Earth Gauge: March Madness
It’s March Madness for the Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) – they want to see how many volunteers sign up this month to measure precipitation in their backyards. CoCoRahS is a nationwide network of citizen scientists who are measuring and mapping precipitation in their communities. CoCoRaHS volunteers help to provide quality rain, hail and snow data used by the National Weather Service, hydrologists, emergency managers, city utilities, engineers, ranchers and farmers, teachers and a range of other interest groups.
Viewer Tip: CoCoRaHS is in all 50 states! Sign up to become a Volunteer Observer with CoCoRaHS in your state to help this network grow. You can volunteer to measure precipitation as an individual or as part of a community or school group. Check out http://www.cocorahs.org/ to learn more.

(Sources: Community Collaborative Rain, Hail and Snow Network. www.cocorahs.org; “About Us,” http://www.cocorahs.org/Content.aspx?page=aboutus)

Let us know here at the Beagle if you do, in fact, decide to participate. Additionally, why not post you findings here and/or on our FaceBook page?

Rock Tumblers Redux: Looking at the Stages of Tumbling

Several weeks ago, I posted an entry to the blog about how to work with your new rock tumbler (this of course assuming that you had received one at some point). Six weeks into my own experimenting with rock tumbler, I'm back with a few lessons and things that I've gleaned from my own experience, which I hope will be helpful to you.

Tumbling is typically a multi-week process, depending on the materials that you choose and the kind of polish that you are hoping to achieve. The choice of materials is important, as tumbling something rather hard with things that are soft will tend to result in the soft things being smashed down into tiny bits. To be certain of the hardness of the materials with which you are working, it's essential to have either a good rock & mineral field guide (I've got about a half dozen), all of which will give you the hardness of most anything you are likely to be tumbling, as presented by the Mohs Scale of Mineral Hardness, which ranges from 1 (talc), to 10 (diamond). If you pick up a field guide and it doesn't have this basic information, put it back on the shelf and find something else. You can also use online resources to determine the hardness of your material: the most thorough of which I am aware is Mindat, which is currently a free site (although with a free registration you can have access to more features). Even with care taken in selecting which minerals and rocks you tumble, you should still expect for anywhere from a quarter to half of the volume to disappear into your slurry bucket.

Polish is also a consideration: some people will like their stones to have different lustres, so it does come down to individual taste. Personally, I want to see just how brilliantly reflective I can make some materials, so I am experimenting with a range of stone.

Assuming that you are indulging in a basic four week-long process, you will also want to choose your grits with care. Before I'd started working with a tumbler again - after a gap of many years - I had expected that four standard grits made of silicon carbide would be sufficient, and hadn't really understood the importance of the pre-polish and polish phases. I can now tell you that these are crucial (this probably should have been self-evident). The pre-polish and polish phases, both accomplished in my case with very fine aluminium oxide polishes, are essential... if you want your tumbled stone to shine, that is.

Time is also an important variable. Your tumbler should come with a guide, or you can find them on the web with relative ease (also in my last post). On my first attempt through the whole of the process, I allowed at least a week for each tumbling stage. This may have been overkill, but on the other hand, I was recently told of a man who left his rough in the final polish phase for something on the order of six weeks! This is probably unnecessary, at least at first. Follow the guides to begin with, until you will get a sense of which materials will require longer than others in the various stages. Again, this often comes down to personal taste.

One thing that is somewhat annoying is that, for the cleaning phase, the use of Ivory Snow flake detergent is often recommened, at least in North American guides. Unfortunately, this product no longer exists. However, if you can't find another plain, pure, unscented soap, the workaround is simple: find a bar of Ivory Snow soap (which does still exist), or any other basic unscented Castille-type soap (Pure & Natural also comes to mind), and use an old cheese grater to make your own flakes. It may help to dry the soap out a bit first - put it in a warm, dry place for a few days, then grate. You will now have soap ideal for use the cleaning phase of tumbling.

Rock tumbling seems, in the shiny new digital 21st century, like something of an anachronistic pursuit, and perhaps it is. But it is also one which connects us with the realities of making something, of doing something, rather than simply paddling around in the virtual pool. Hopefully, you will take as much enjoyment from it as I am.

New Merchandise from Tucson - Part 2

We have been able to purchase some exceptionally nice Lamna species teeth as well as Megalodon teeth while here in Tucson. The latter are very nice indeed in that they vary considerably in color rather then being just the run-of-the-mill black. For the Lamna teeth one must always look for the cusps on either side of the main tooth. If the cusps are missing the tooth isn't as valuable.

The Lamna teeth are almost always white to a light tan in color and are very sharp!

The Megalodon teeth are the right in these pictures and the Lamna are directly above on the left.

Below, on the left are teeth from the mosasaur species globidens. These were shell-crushing aquatic reptiles that died out 65 million years ago. Most of you are familiar with the more common mosasaur teeth we sell, but these are entirely different and much rarer.

Below on the right are ammonites from Madagascar. These have been polished to expose the sutures that marked the separations between the internal air spaces the animal used for buoyancy.

Finally, we have also been acquiring some minerals specimens, and for the first time we have purchased some polished quartz crystals about 1.5" to 2" long. These are pictured below.

New Merchandise from Tucson

Here are some photos of the merchandise we have acquired here in Tucson. First we bought some fossil fishes from the venerable, jolly and highly knowledgable Bob Finney. We bought three larger plates and 65 unprepped 4" to 6" "singles". The latter will be put in our Fossil Prep kits we. The former are pictured here; the first is a triple plate with two Knightia and a Diplomystus:

The above place is ~18" x ~14". Next is a 12" x 12" plate with a large Diplomystus:


Finally, we acquired a very nice Mioplosus and preditory perch that lived in the lake 55 million years ago. This plate is 12" x 8":

Those of you who really like Fossil Lake fishes from Wyoming should stop by the Beagle next week to see these pieces in person.

Where we stay in Tucson during the TGMS

For those of you who have not visited our the home of our friends, Joe and Cheri, in Tucson we wanted to show it to you. We have enjoyed Joe and Cheri's hospitality for 6 years during our visits to the Tucson Gem, Mineral and Fossil show. In fact, it was Joe and Cheri's insistence that we stay with them and visit the show back in early 2004 that first brought us here.

Anyway, to take a look, visit this web site: www.longrealty.com/AZ/Tucson/85718/homes-for-sale/5441-E-Gleneagles-Dr-46575313, and take a virtual tour of their home, which is now for sale. Any of you wishing to purchase a new home in beautiful Tucson could certainly do far worse.

We'll be on our way again today for more exploring and buying. Keep watching for information on the new merchandise we will be acquiring.

Also, please post any comments, especially if there is something in particular you would like for us to acquire.

Let's take a trip to Utah to collect Trilobites

Well, while here at the Tucson Gem, Mineral and Fossil Show Carol and I found a group through which we can offer a trip for 10 to 12 persons to dig for Trilobite fossils in Western Utah. We'll have lots more information here, as well as on our web site, but the important thing is, "all fossils discovered during the (dig) belong to the person who discovers them! (n)o mater how rare or valuable they may be." We want to offer this trip to our Beagle Society and Science Club members and families first.

Those of you who went on the Great Montana Dinosaur Hunt will recall that we could not keep anything that was of significance to the permit holder. However, just like that trip, HMS Beagle will be handling all of the trip details including lodging, meals, access to the collecting site (over 300 sq. miles) and more. There will be bonfires each evening, fantastic scenery (the West Desert of Utah), workshops on digging techniques and field curation of specimens, and at leaast 20 different species of Trilobites can be found on this largely unexplored land.

The two gentlemen in the picture are Jake Skabelund and Jason Cooper. They will be the hosts for the dig. Let us hear from you if you think you will be interested in this experience.