Monthly Archives: May 2011

Week 1 has been very busy and week 2 is almost to begin.  We were lucky with the weather, but this week looks to begin the inevitable warm up that we all knew would come.  This week the geophysics group went on a field trip to get the regional setting (Monday), learned detailed surveying with the TOPCON differential GPS (Tuesday), conducted a gravity survey, and a magnetic survey (days dependent on group assignment).  The week ended on Saturday with another field trip out west to see some different formations.

The regional field trip went well and we scrambled across some slopes to see most of the section that the geologists would be mapping and be very familiar with.  As a geophysics student I was more interested in the rock properties, what methods we could differentiate them with, etc.  This trip did help put things in a big picture geologic perspective though.

The differential GPS surveying went well despite a few equipment setup issues, which were to be expected with new users.  The basic premise of the system is to leave a very precise GPS unit in place all day while another identical unit is used as a rover.  The two data sets can then be merged using the base to correct for signal attenuation by the continually changing atmosphere and other error sources.  In general sub-centimeter accuracy is achievable.  This accuracy in elevation is especially important in gravity data processing since 1m makes .3086 mGal difference in the data.  While some complain that taking 2 minutes to get a GPS fix is unreasonable I remind you that we are getting a very accurate position on an irregularly shaped rotating planet FROM SPACE... it's amazing it dosen't take longer.

The gravity survey looks at density differences in the subsurface while the magnetic survey examines differences in magnetic susceptibility.  We are interested in contracts between sediments and basement or with a dike especially in this area.  After the processing I will post some results, but I know the magnetometer went crazy when I passed over the suspected location of a large dike.  The gravity survey should also be helpful, but the gravimeter does instill a certain amount of fear in everyone since it is ~$100,000 and VERY easy to break.  Omar is modeling the magnetometer in this picture.

Finally, we went on another trip Saturday which involved me getting some nice rocks with chlorite in them for bookends from a tailings type pile in a field.  This week will be seismic week, so stay tuned for updates and pictures of our new (hopefully) 700m long seismic line!

The past few days have been working to get a solid radio link to downtown.  The internet signal comes up on a 5.8GHz link, is distributed over a 5.12GHz mesh around the camp, and is repeated to others on a 3GHz haul over the canyon.  Below is a picture of the stack at the top of the camp on the study hall.  The repeaters are mounted on the sides of cabins.  The current link is slow, but a new circuit will be installed downtown giving us a fast connection this week.  Also included is a picture of the geophysics server (named thor) and the associated gear.

We also worked on setting up the thumper.  This is a machine that attaches to a trailer hitch of any vehicle (truck, ATV, etc) and impacts the ground with a great force.  We use this in seismic imaging.  Normally we use a sledgehammer for small surveys, but that can get tiring.  For large, deep surveys explosives are used, this machine is a great middle ground.

As you can see there is still some work to be done.  Tomorrow the hitch will be modified and in the evening I'll be building some custom brackets and mounts for the controls and battery with Dr. Keranen.  We'll use aluminium angle iron to build most of the mounts, pictures will follow.

Tomorrow we all leave early for a regional trip to get the general geological/tectonic setting of the area.  This trip will be both geologists and geophysicists.

This is the first in a series of posts I'll be writing about my experience at the new Bartell field camp. This camp will serve as the base for summer geology/geophysics students. Geologists will be here 5 weeks, geophysicists 3 weeks. I arrived early to setup computer equipment and help get things going around the place.

I arrived Wednesday and unloaded the server, 10 laptops, associated wiring/network components, and my field gear. More on the setup in the next post when we have internet and the rest of the network up and running.

The first night here the freshman field trip was also at camp, spending the night before departing to Dalhart, TX. We all hooked up the projector, hung a sheet, and had a movie night in the dining hall (complete with popcorn). The movie was 2012, one of the better geological comedies if you ask anybody there.

The camp site is beautiful and my cabin is at the top, affording the best view. This view comes at the price of walking a VERY steep trail, and at 6,200 ft. it's easy to get a bit winded. After a couple days it is not a problem though.

So far the weather has been very cool and rainy in town, but fairly dry up at camp. It's hit freezing at night making a sleeping bag necessary in the cabins. The peaks off in the distance are still snow covered, but today were obscured by rain shafts.

Stay tuned for a tech update tomorrow and then the arrival of the rest of the crew on Sunday. The next few weeks should brings lots of interesting field work and interesting results.

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Location:Silverado Ct,Cañon City,United States