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.

Historical Geology Field Lab

For my historical geology lab, we took a field trip to Midwestern Utah. I have way too many photos and experiences to share, so I decided to divide the trip into different sites. I'll start with Notch Peak.
Seen in the photo above, Notch Peak is the highest peak in the photo. Notch Peak is formed by the Weeks formation, overlain by the Notch Peak formation, both Cambrian in age.
A Jurassic granitic intrusion caused contact metamorphism of the Weeks formation (basal layers of Notch Peak) and Lake Bonneville deposits make up the basin sediment.
The contact metamorphism was the highlight of this site. That's my instructor, Forest Gahn. (Can you spot the rock hammer on the outcrop?)
BYU Idaho students seated on the outcrop during the discussion, the altered Week's formation, capped by Jurassic "granite" (jointed diktytaxitic quartz monzonite), with Notch Peak dominating the skyline.The photo below shows a xenolith of the altered Week's formation included in the granitic rock. It also shows the detail of the altered Week's formation. Notice the interfingering of the lighter calcitic layers and the darker silicic layers and the garnets that have formed in the calcitic layers. This is an impressive outcrop -a great example of contact metamorphism.That's the start of my "digital unloading". I'll be posting more as I find time to do it. In the mean-time, I've got to pack for my trip to southern Utah and the Grand Canyon.

To Wegener

Alfred Wegener (1880-1930)
Wegener was a German physicist and an explorer in the truest sense. His most noteable contribution to modern science was his theory of continental drift. His observations from around the globe led him to put together pieces of evidence that suggested that earth's continents were once fitted together in one supercontinent, and that they had drifted apart to their current position. But Wegener had no valid mechanism that would explain the movement of a continental bulk of rock, and his ideas were well ahead of his day.

Concerning Wegener's drift theory, R.T. Chamberlain said:
"Wegener's hypothesis in general is of the foot-loose type in that it takes considerable liberty with our globe."

What Chamberlain (and others) didn't appreciate was the considerable amount of valid data that Wegener had collected that supported the idea, he only lacked the mechanism that could concievably achieve the process. He was on the verge of one of the greatest breakthroughs in the history of geology as a science. The views of the day caused even the best scientific minds to blatantly ignore the valid data that was laid before them.

"It is just as if we were to refit the torn pieces of a newspaper by matching their edges and then check whether the lines of print run smoothly across. If they do, there is nothing left but to conclude that the pieces were in fact joined in this way." -Alfred Wegener.

Wegener died decades before his work would be appreciated. It wasn't until the sea floor was explored in more depth that the driving mechanism Wegener sought was discovered, sea-floor spreading at mid-ocean ridges.

Photos from the Black Hills in Southeastern Arizona

One highlight from my holiday break in Arizona was my trip south to Safford to visit David and Adina Morris. David, my mentor in Geology, and Instructor of Geology and Astronomy at EAC, took me out to the Black Hills (the northern end of the Peloncillo Mountains -a Miocene volcanic mountain range) roughly northeast of Safford en route to Morenci. The above photo shows the exposed plumming system of a volcano -a basaltic plug dome.
The photo below -a caliche breccia with basaltic clasts.
An old pumice mine with David in the foreground, for scale :).
A more detailed photo of the ash deposits at the pumice mine. Notice the lighter-colored clast near the bottom. The yellow tint to it is indicative of sulfur-rich groundwater percolation. There was an entire layer of tuff which had been altered by hydrothermal processes and exhibited similar coloration.
A scoria cinder pit. This was once the site of scoria harvesting, most likely for landscape purposes.
A more detailed shot shows the size of some of the basaltic clasts in the scoriacious matrix. Notice the silicic deposits in this clast -amygduloidal scoria.
Amygduloidal basalt, and the single jack. WARNING! Use protective eyewear! (Some nice chalcedony is visible just to the left of the hammer -and all over the photo if you look closely)
Some of the chalcedony amygdules are quite large, and lovely.

Secret Tunnels

This is the entrance to the ice caves north of Rexburg; they're basaltic lava flow tubes. As lava flows, the outer layer exposed to air cools more rapidly than the molten material in the flow's interior. A basaltic rind forms, successive flows add layers to the flow tube walls, and the lava in the tube shallows as the flow decreases to a stop. This flow tube has since been percolated by water which, in Idaho's climate, turns to ice. Most of the cave floor is covered in thick ice layers. The combination of ice and basalt flow textures offered a double-helping of fascinating geology. The ice formed stalactites, stalagmites, and dendritic "feathery" snowflake-like crystals. There were also some neat flow layers and fractures in the ice. Here's a shot of ice crystals covering the ceiling:
Beautiful basaltic textures:
Me and the roomies (Kyle, Parley, me, Tom, and Trevik). At this point, the tube was segmented into an upper and lower passage; as the flow level in the tube dropped, the surface cooled and formed a shelf across the larger tube. That shelf is where we're perched for the photo.
Here's a shot of the ice-covered floor. Half the time, we were on our backs sliding along, pushing with our hands or feet. I came away from this cave with some bruised knees and elbows and a few scrapes on my fingers -totally worth it.
THE "END"

Over the Thanksgiving Break

I travelled with a friend back to Arizona for the Break. She was nice enough to stop for her rock-geek passenger to see some ash fall and tuff units. This road cut is on the stretch of Highway 20 that connects I-15 with Highway 89, just southwest of Beaver, Utah. The geological map I looked at labeled volcanics of the region as Bullion Canyon volcanics. The lighter-colored units are ash deposits and the massive darker units are rhyolitic tuff.

The ash units contain concretions.


A real treat on the way back north was the slight detour to see horseshoe bend just outside of Page, Arizona. It's a very photogenic meander in the Colorado River. We got there just as light was fading after the sun had set. No, this picture isn't mine. But the one below it is. The meander is so deep that it's difficult to get the whole thing into one shot. I may try to piece my photos into a panorama.

Igneous Rock Exam

The pictures are cruddy. Fluorescent lighting will do it almost every time.
Last week's Igneous Rock ID exam went well. I went into the exam feeling pretty comfortable, and left it feeling like I had done well.
Today, I got my ID portion of the exam back; 98%.
I once again give credit to David Morris for a job well-done. What would school be like without that firm groundwork of understanding from David?I shudder to think.

Some of the samples from the exam