Wednesday, December 5, 2007

Neal Immega - A Permian Pool Table?

Did I discover a Permian pool table near the Dimetrodon dig site?

Let's do some investigation and see what answers can be found. Hundreds of two-inch spheres are concentrated in an area with a radius of about 100 feet.

Sandstone spheres all over the ground. A GPS device is present for scale.

A closeup view of several of the spheres.

When you look closely at just one of the spheres, you see that they are made up of sandstone and a few of them show inclined bedding planes (or layers), of the type that are found in rivers.

Geologists have characterized sandstone deposition in many environments. Beaches produce cross-bedding with an angle of about 5 degrees. Dunes are very different, because the grains are wind-blown and thus have cross-bedding of about 30 degrees.

Ripples in rivers have cross-bedding that are between these two extremes, which is why I predict that these sands (in the spheres seen above) are from a river deposit. This prediction is consistent with the oxidized red sands and shales that typically form in a desert environment.

What is inside of them? I could break some open, but I do not need to. A naturally broken and weathered surface (as seen in the close-up above) frequently shows more detail than a fresh break.

This is a photograph of one of the broken spheres showing rings of an iron mineral called goethite (hydrated iron oxide). We have enough information to make an interpretation.

Recall my previous entry on the spotted sandstone. In that case a bit of rotting organic matter reduced the iron in the rock to form a green spot.

The rock spheres at this site are caused by a bit of organic material that changes the chemistry of the water in the sandstone, causing precipitation of iron minerals. The banding is called Liesegang and you can read all about them by putting in “liesegang rings” into Google.

4 comments:

Anonymous said...

I just got back from a weekend trip to Lake Powell in southern Utah and found spheres exactly like this embedded in and eroded from red sandstone along the shore of one of the canyons. Dumb me, I didn't take pics of the boulders with the balls in them, but I did bring a few back to try to figure out what they were. There were easily hundreds of them, if not thouands, embedded throughout the entire thickness of 10' + boulders on the shoreline, and hundreds more eroded out and lying on the narrow beach. In addition, I found a layer of sandstone shelf with loose/embedded sandstone "grains" that looked like oat grains (thick in the middle, taper at each end, about 1/2 inch long). This is the first site that came up on Google when I started looking for "sandstone spheres" in image-search and they are very much like what you found, but throughout a huge strata, laid down over a VERY long time. Very interesting!

Dominick said...

check this | there | this site | here | this page | there | check this | this site

there | this page | check this | this site | here | this page | there | check this

there | this page | check this | this site | here | this page | there

tiendas eroticas said...

Hey, there's a lot of effective info here!

Anonymous said...

very nice information.
regards
rohit arora