Monday, April 27, 2009


The BYU-Idaho Geology Department recently acquired a new digital camera and software for creating digital images of what you see through the lenses of a microscope. These are called "photomicrographs". These first few were slides of thin-sections of rock we use in our crystallography lab. I haven't got all the details worked out for mounting the camera and getting the optimal lighting conditions, but BYU-Idaho now has the capability to produce these things. And I'm the one who gets to figure out the details. It's exciting!

Tuesday, April 14, 2009

Garnet, Staurolite, and other Miscellaneous Schist

Yesterday, my friend and I went to Henry's Lake near Island Park, Idaho, just west of Yellowstone. The alluvial fans along the north shore's mountain front are rich with metamorphic mineral and rock samples.
This road-cut is a prime garnet-collecting site.
Here's a sample of the variety of metamorphosed pelitic rock present at this site.
Here's the road-cut that contains abundant staurolite (from the Greek "Stauros" meaning "cross") samples.
There was also a good amount of tremolite present at both sites.

Fossil Mountain

Fossil Mountain lies in the Southern end of the confusion range. In the photo above, the Eureka "quartzite" (in reality, a sandstone) tops the sequence, The Crystal Peak dolomite (the gray strata), the Watson Ranch "quartzite" (also a sandstone), then the Lehman Fm, Kanosh shale, Juab limestone, and Wah Wah limestone (I had fun saying that name).
Listric normal faulting has rotated strata, then a younger volcanic system emplaced the horizontal lava flows above (an angular unconformity).
Our instructor, Forest Gahn discusses stratigraphy and correlation of units across the valley. The Eureka unit near the top of the sequence lies at the valley floor and dips toward us: evidence of listric normal faults. Fossils found at this site: nautiloids, orthid brachiopods, gastropods, crinoids, ostrocodes, and sparse trilobites (typically fragmented); fauna of the Early Ordivician.
Surficial layers of sandstone units are bioturbated (burrowed), another indication of transgressive sea level.

U-Dig Trilobite Quarry

The U-Dig Trilobite Quarry is located in Western Utah, 34 miles north of Delta. The carbonaceous shale at the quarry is part of the Wheeler Formation.
I brought home abundant samples. Shown in the photo above are Asaphiscus and Elrathia. I also have some small samples of Perenopsis and the inarticualte brachipod, Acrotreta; all index fossils of the M. Cambrian.

More from the Historical Geology trip

Our first destination on the trip was the Museum of Ancient Life at Thanksgiving Point in Lehi Utah. I've driven past this place several times. From the outside, you'd think it was a hyped-up tourist attraction, with not a whole lot of scientific merit. Boy, was I wrong. Our host, and founder/designer/director of the museum, Cliff Miles has been pioneering recovery and restoration methods for fossil skeletal remains. We got to experience a tour of the behind-the-scenes restoration shop of the museum. In the above picture, Cliff shows us a restoration-in-progress of the neck of a barasaurus. Cliff's team pioneered the use of Bond-O in the restoration of fossils remains. (I found that fascinating. It's genius)
The above photo shows a sample being restored from out of the jacket it was transported in. Cliff explained that samples are more damaged the longer they remain in the sealed jackets. As the jacket plaster dries, it contracts and results in fracturing of whatever's inside. So his team works as fast as they can to get samples processed and out of their jackets.
A view of the Cambrian Fauna. I was impressed with the dioramas. How else could you get some visual sense of what ocean life looked like?
My reflection in a polished Banded-Iron Formation (BIF).
Archelon -massive sea turtle of the late Cretaceous.