16 October, 1998
Welcome to the world of paleomagnetic geology!
This journal entry is a summary of my June, 1998 trip to the University of California at Davis. This trip to UC Davis was VERY worthwhile for many reasons. First, it provided the opportunity for me to visit with my PI (Principal Investigator), Dr. Ken Verosub, and get to know him better. It also gave me the chance to become familiar with the research we will be working on in Antarctica, and to use some of the technology that will be employed in the field. We had the chance to talk about the various aspects of the TEA program, and I felt that a lot of questions were answered, (for both of us). Finally, I was able to share with Ken WHY I wanted to be a member of the TEA program, and how I feel I can use this experience with children, teachers, and other adults.
In the past three weeks (late September/early October) I have given about 16 presentations at schools in my area. I have met with elementary, middle, and high school students and teachers, and a science methods class at Northern Illinois University. All of my preparation has maximized my ability to teach about a VERY exciting topic: ANTARCTICA !! I feel more confident about basic knowledge of the Cape Roberts Project, logistics of my upcoming trip (I leave tomorrow !!) and how I fit in as an active member of the paleomagnetic research team. The work is just beginning !!
Back to June...I started my first day of my visit to UC Davis with a brief tour of the campus, and ended up at the geology building. Ken didn't waste any time getting me into the lab and working with equipment that would familiarize me with paleomagnetism. Most of the equipment that we used to measure samples was in a magnetically shielded room. This room is designed to produce a very low magnetic field, and to shield out the Earth's magnetic field. We sat on plastic chairs and used desks/tables made of plastic or wood. The machinery is extremely sensitive and expensive.
Using a cryogenic magnetometer, I measured the magnetization of small samples of sediment. The cryomag (as it is called for short), uses super conducting electronics to measure the magnetization of the sample. This process involves lots of little steps, and it was good to have the chance to run through a series of tests and repeat these steps many times. All of the information and steps were recorded on a special computer program. In the field we will use a portable magnetometer. I think it was great to be able to use this larger one to start off.
Next I moved to an AF (alternating field) demagnetizer. This machine removes the secondary component of magnetization of the samples and allows you to see the primary component of magnetization more clearly. Again, lots of smaller steps-- turning the sample three different directions to perform various functions, and then using the cryomag to go back and measure the magnetization of the sample. We repeated this process by demagnetizing the sample at various levels.
I learned a lot about how the drill core samples are transported...in something called a mu-metal shield. This is a box (or container of some sort) that shields the magnetic field of the Earth. I also saw the drill press that is used to drill the core samples. The core that is brought up by the drill in the field is about 3 inches in diameter. They slice this in half and lay the flat side down, curved side up. The drill press has a diamond blade that cuts through the rock/sediment core, resulting in a small cylindrical drill core sample that is 1 inch long and 1 inch in diameter (about the diameter of a quarter).
Later I helped Ken unpack some of the equipment that was used in Antarctica during the 1997 field season (last October through December for this project). It was shipped back to UC Davis and some of it was just being unpacked for the first time. This was interesting because this IS the equipment we will be using when I get to the Crary Lab in McMurdo. A MINISPIN (which is a high sensitivity, portable, slow speed spinner fluxgate [type of electronics] ) and a small Molspin shielded demagnetizer were the two most important machines I became familiar with. After assembling the demagnetizer, Ken showed me how both machines worked.
The next day I used both machines to test 5 drill core samples from last year's Cape Roberts Project. First I tested each sample with the mini- magnetometer to see what their magnetization level was. I recorded these by hand, because we didn't have the computer software that accompanied this machine. Next step...Ken added some magnetization to each sample. He used a piece of equipment called an automated long-core cryogenic magnetometer. There are only about 10 of these in the world, and UC Davis was one of the first places to get one. It is a VERY expensive machine. I went back to measure each sample using the mini-magnetometer to look for changes in the level of magnetization.
Finally, I went to the demagnetizer and went through quite a few levels of demagnetization and measurements using both machines. I was constantly up and down, moving back and forth between the two. I collected tons of data and entered my results into a spreadsheet program on the computer. Later Ken came in and rearranged the data so we could print it out in several different types of graphs. When using these graphs it was easier to interpret the information I had collected.
Ken gave me some drill core samples to take back home and use for my presentations. I have samples of each of the three different types of rock...igneous, sedimentary, and metamorphic. These have come in handy as I've tried to explain what I'll be doing in Antarctica. Ken also gave me some small clear boxes filled with samples of sediments.
The last two machines I learned about were a magnetic susceptibility meter and a thermal demagnetizer. The first one measures how susceptible the rock is to magnetization by an external magnetic field. The second demagnetizes a rock sample by using heating and cooling chambers.
The scientific study of the cores collected in the Cape Roberts Project will include not only magnetostratigraphy (the study of magnetic properties), but biostratigraphy (the study of fossils used to date sediments), petrography (the study of rock types), mineralogy (the study of minerals), and sedimentology (the study of the conditions under which the sediments were deposited). I KNOW I have a lot to learn, but that means a lot to share as I continue on this adventure.
Stay tuned for more information on the Cape Roberts Project and my trip to the big white continent !!
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