In the Lab
Samples of lithic material cannot undergo geological analysis straight from the field. Skilled technicians must process a sample through a series of time-consuming steps to prepare each for detailed study.
In the Lab
First, unaltered field samples are chosen from a site for further processing.
Samples are then cut using a rock saw equipped with a diamond saw blade. This step produces a thin rock slab.
The next step involves cutting the slabs into thin-section billets, rectangular blocks about 1 inch by 1/2 inch in size.
The billets are then ground flat on a rotating lap using a series of aluminum oxide and diamond abrasives.
Once the billets are ground flat and smooth, they are mounted to glass microscope slides using a heat-activated epoxy resin.
Mounted samples are first trimmed with a rock saw and then shaved down to a thickness of approximately 0.05 mm using a vertical diamond-impregnated lap. Both stages are done on specially designed-thin-section machines.
The final part of the process involves several stages of grinding and polishing using increasingly finer grits. The thin-sections eventually develop an excellent surface polish.
The end result: three of the many slides of lithic material prepared for this study (shown larger than actual size.)
Copyright © 2004 by
The University of South Alabama
Updated: 9/5/2004
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