Devils Tower

My Dad asked me to write what my most interesting experience in geology was. It was when we stilled lived in Montana, we went to Devils Tower. I thought of it as a big rock that was not a mountain. I liked camping there and waking up to see the sunrise. We took a walk around the base and we saw a huge Pine Snake!

Sam

What I see on the way home from work

So every day coming home from work, I see this outcropping on the side of the interstate.

In the big picture it is a fairly typical outcrop of Columbia River Basalts that are ubiqitous in our area, but there is more to the story. There are really two layers of Basalts here separated by a layer of baked paleosoils.

What is interesting about this picture is it represents the horizon between two separate flows. The upper layer represents the Frenchman Springs Basalt, the lower member of the Wanapum Flow. The Wanapum flow originated from dikes between Pendleton and Kennewick, WA about 15.3Ma and covered.

In between the two basalt flows, there is a baked layer of paleosoils 0.5-1.0 m thick. This red layer is the Vantage Soil Horizon and represents soils weathered in 200,000 years between flood basalts.

The older  (lower) Grande Ronde Flow originated NE Oregon ending about 15.5 Ma.  The Grande Ronde flow was the most extensive of the CRBs with as many as 18 individual flows covering up to 160,000 km2 with at basalts. Sentinel Bluffs layers are generally only 10-30m thick, but some of the lower Grande Ronde flows were over 80m thick.



Figure Taken From http://geology.isu.edu/Digital_Geology_Idaho/Module10/mod10.htm



This particular member of the Grande Ronde Flow originated from the Chief Joseph Dike Swarm, a series of dikes about 100 miles NE of this outcrop. This is interesting in the fact that today, these dikes are separated from this outcrop by the broad anticline which makes the core of the Blue Mountains

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Washington DC

Last week was THE RODEO in our town, as the kids had a week off of school so had decided to go somewhere else. So somewhere back in the spring we decided to go out to Washington DC to see family, see the sights. One of the things I wanted to make sure and do was get outo and see the Billy Goat Trail, which Callan from Mountain Beltway is constantly blogging about. We were even lucky enough that Callan took a break from field sampling to come up and give us a guided tour.

Even the non-geologists in our group really appreciated having such an exellent guide explaining the geology of the area. As much as enjoy the fact that Sam likes doing all this geologizing with me, I think her true scientific future lies in herpetology, as she spent most of the hike looking for frogs. Here she is looking for frogs in one of the potholes.

and later on Callan pointed out a lizard, which she quickly caught.



 We ended the hike at the Great Falls of the Potomac, which due to the water levels being low were mostly rock.

In addition to the BGT, we went to a number of monuments and museums. One of the museums we visited was the Smithsonian's Museum of Natural History.

On our hike of the BGT, Stanton had asked Callan a question about the shining (mica) minerals in the rock. The conversation led to shiny things and the Hope diamond, which is on display at the Smithsonian

Callan remarked that in the room with the Hope Diamond, he was actually more impressed with the big piece of copper that everyone ignores. Stephanie sort of snickered and assured me that she would be looking at the diamond, but when we got to that room, even she agreed that the piece of Native Copper from the White Pine Mine (Michigan's Upper Peninsula) was really quite impressive.

I actually liked the nice piece of gneiss,

but everyone did agree that the Hope Diamond may not have been the highlight of the room.

Philip