This unit is under the aegis of Dr. Ross Powell, whose principle interest is glacio-sedimentary processes. The vehicle is used to investigate phenomena which occur at the ice front and beneath floating ice in Antarctica, Chile, Glacier Bay in Alaska, and off Svalbard in the Norwegian Sea.
Manufactured by Deep Ocean Engineering, Inc., the submersible carries an impressive array of sensors. There are two video cameras, one black-and-white and one color, and a still camera with a flash attachment capable of taking stereo pictures. It has forward-looking and side-looking sonar, and carries a tracking system which locates it with respect to the operator's position. It can also be made to locate itself absolutely using GPS. It is equipped with a grab sampler capable of taking 6 sediment samples per dive. Other instruments are a current meter, dissolved oxygen sensor, and a CTD meter ( Conductivity, Temperature, Depth ). The suspended sediment load in the water column can be estimated by optical backscatter if the load is high, and with a transmissometer if it is low. The sub's tether is 500 meters long, and permits control of the craft along with real-time uploading of data and video images.
The truck-mounted GeoProbe drill is a vital research tool for our Hydrogeology and Environmental Geosciences and Glacial and Sedimentary Processes research programs. It was made to our specifications by the GeoProbe Company of Salina, Kansas, and became part of our facilities in early 2007. Dr. Melissa Lenczewski has primary responsibility for the GeoProbe, which she shares with fellow geologist Dr. Jay Stravers, geophysicist Dr. Philip Carpenter, and soil scientist Dr. Mike Konen of the Geography Department.
The drill can be operated in two modes, one as a push drill and the other as an auger. The push drill, which operates by pushing the drill string into the ground without spinning it, is designed to retrieve core samples and is used to characterize the stratigraphy of a site or to retrieve samples for chemical analysis. The auger can be used to set piezometers and monitoring wells, or to overdrill and retrieve a stuck push-drill string. The maximum depth is ultimately limited by the amount of drill string we possess, and we presently have sufficient to reach 50 feet with both the push-drill and auger, geological conditions permitting.
Geophysical appliances we use with the GeoProbe include the Cone Penetration Test ( CPT ) and the Electrical Conductivity (EC) sondes. The former can measure the resistance to penetration of the tip of the drill string, the resistance to advancement of the string caused by friction with the sides of the hole, and liquid pore pressure. The latter is used to make a log of electrical conductivity as a function of depth, which can then be correlated with the stratigraphy as determined from recovered core.
There are thirteen of these excellent microscopes available for student use in research and course work. We also have the equipment and expertise to teach the ancient and honorable art of making thin sections, for those brave souls who are determined to acquire the skills necessary to make their own.
Even though our Environmental Scanning Electron Microscope doesn't require that all samples be coated before use, it can still be useful to do so. In a scanning electron microscope, samples are "illuminated" by an electron beam, which is an electric current. That electric current has to be able to flow to ground, so the sample must be conductive but most minerals, rocks, fossils, and organic materials are not. The problem is solved by evaporating a very thin coating of carbon or a noble metal, in this case gold, though a mixture of gold and palladium is also commonly used, onto the surface of the sample. The idea is to coat the sample such that the surface is not obscured but that the sample surface becomes conductive from the presence of the carbon or metal film.
Our X-Ray Fluorescence Spectrometer is where powdered rock samples are made into the fused pellets for analysis. We can also make boric acid backed pressed powder briquettes if the analytical scheme requires it. See Sample Pellet Preparation Procedures.
A water-lubricated saw is most commonly used to cut chips from hand samples. We also have two oil-lubricated saws capable of handling very large samples, but these are rarely used because of the difficulty involved in cleaning the oil off the rock when the cut has been completed. We also have a thin-section machine.
Other ways of making "little ones" out of "big ones" include small, medium, and large chipmunk crushers, a rotary pulverizer, and a Spex Shatterbox with both tungsten carbide and alumina mills. The Shatterbox can reduce a crushed sample to a powder similar in grain size to flour. The chipmunk crushers are used to reduce the sample to a grain size that the Shatterbox can handle.