Based on our research on the Chinle layers in Lee’s Ferry, my hypothesis has been proven incorrect. Katherine and I used optical microscope and scanning electron microprobe to help use identify the physical and chemical characteristics and how the changed along the trail we used to sample the Chinle formation. My chemical analysis indicated that the layers were more sodium rich than calcium rich. The only areas with strong calcium concentrations were areas that contained sandstones. Other information we were not expecting to find were evidence of uranium leakage in the area and styolites that indicated the deformation that occured in the region.
An small earthquake hit near the Lees Ferry area last Saturday. It was only a 2.8 magnitude, but large enough to be felt. (USGS) Earthquake activity is interesting in this area since I just had the chance to map it and there is rarely an activity in the area since it is in the Colorado Plateau.
Picture of Sandstone from the Chinle Formation at Lee’s Ferry. (Studied March-April 2013)
This past week I have started working on my analysis of the changes in chemical composition throughout the different layers that were sampled in the Chinle. The picture above exemplifies some of the unexpected material that was found in the layers. I was expecting to find ash in all the samples collected and they appear the same in hand sample, but look completely different under the microscope. I am excited to present the full results at the end of the semester.
Back from Lee’s Ferry and Spring Break is over… The project that I have been researching about bentonite in the Chinle formation was much different than I imagined. I was hoping to sample over a larger area, however, my partner and I were able to collect sample along a trail in areas we had not anticipated looking at. At the top of the trail we believe may be the Petrified Forest Member within the Chinle formation, which was our first station of samples. I am hoping to see different variations in those samples compared to the other samples we collected near the Chinle and Debri Flow contact and samples closer to the Paria River. I was also able to sample all the different color bands found in the formation we mapped to identify differences. Overall, the research is going smoothly and the stations for sampling in the field provided interesting results. One of the most interesting results was there was highly consolidated material imbedded within unconsolidated material. The material had a distinct color change and I believe may be a different material. SEM anaylsis is scheduled soon, but in the meantime other analysis will be done.There is one paper in particular that will be perfect for direct comparison of our site. And I will add a location from outside the area we were for more comparison.
Tomorrow we head out to Arizona to finally arrive at Lee’s Ferry. We will be able to take the knowledge we have been developing over the last few weeks and relate that with the field work we do. I am excited to camp out in the area for about a week and see more of the geology out west. I plan on taking many pictures and many samples to add to my collection!!
Based on my research from the last few weeks I am hoping to test bentonite that is calcium or sodium rich. I found a great article “Transformation of Smectite to Illite in Bentonite and Associated Sediments from Kaka Point, New Zealand: Contrast in Rate and Mechasim,” which will be a great resource if our bentonite samples are not as simple as calcium and sodium rich . I hope to compare our field results to the results found in this paper. The paper uses similar methods that we will be using such as SEM imaging (Smectite).
(Bentonite layer in N. America- picture from great AGU blog with information about bentonite layers on the eastern side of the United States and how they are correlated to other parts of the world AGU). This could help Katherine with some of her age dating as well.
Dr. Madden lead me to a great article found in Elements, “Bentonite and Its Impact on Modern Life”. This article gave me an idea for another aspect for the bentonite that I can test when returning from the spring break trip. The article only compares sodium and calcium bentonite and the differences between them. The article exemplifies how Ca-bentonite has a lower swelling capacity and does not adsorb as much water as Na-bentonite (Elements). When I found this information I decided that if the bentonite samples we collect are rich in calcium and sodium, I could test whether it was more sodium or calcium rich based on how well the clay stays suspended in water. The calcium rich bentonite should not suspend in water well. I could used a specific amount of water and same about of clay.
Other interesting facts that the article stated were that we should find the layers of clay near areas where water was able to penetrate the layer, and therefore we should see these affects. It also stated what type of textures are present in these two types of bentonite which will help us identify them in the field.
We will further use this article to discuss the present day uses of bentonite in our final projects, such as enviromental sealents, desiccants, metal casting, drilling fluids, and cleaning agents (Elements).