studying slip rates in the Northern San Andreas Fault
Post date: Jul 29, 2013 9:06:03 PM
In the last two weeks we have continued the processing of the samples I talked about last time.
In the last entry I mentioned the multiple acid baths that each sample goes through. After this, each sample has been leached so much that quartz is pretty much all that’s left. However,
there are still large particles in the sample that need to be removed to continue processing. In order to get out the heavy magnetic particles I run each sample through a Frantz machine in the
Materials Separation Lab, which is really a large electromagnet that pulls out the heavy magnetic particles out of the sample. Next, a small portion of each sample is taken out for a Partial Sample Aliquot (PSA), where we learn what really makes up each sample. Later, samples are run through columns that remove the ions from the samples. In the end, we will pull Beryllium from the Quartz, which can be dated with its isotopes. If we know the ages for these rocks, we may be able to find out the slip rate for faults.
Also in the past 2 weeks, we went to Sanborn County Park twice to examine it as a possible candidate for studying slip rates in the Northern San Andreas Fault. Surprisingly, there is not much precise data on the slip rate for this area of the fault. The San Andreas runs straight through the park and provides examples of beheaded streams (mostly dried up now) and offset channels. We used LIDAR maps of the area to be able to see the land on a much larger scale. In these map, the location of the fault becomes much clearer. In the park, we also spotted a family of ducks feeding in the thick algae of a sag pond.
