Over the last few weeks Katherine and I have worked towards picking a few hypothesis that we can study for the rest of the semester. My emphasis of the research will be focusing on the mineralogy, crystal morphology, sorting of the grains, rounding, and determining if there are fossils present in the clay layers. Together we will both focus on looking at the depositional structures that are present in the layers above and below the bentonite and whether the they differ in multiple locations. We have found articles from New Mexico and Serbia that we would like to compare our on research to.
Our hypothesis states that there will be multiple depositional structures in the layers above in below in varying locations. We will test it my taking samples from multiple locations along a measured sectioned. We will also make a stratigraphic column that will represent our results. Katherine will be expanding on the depositional structures in her hypothesis of age dating. We will also be looking at any defining features that may set the measured section apart.
My hypothesis is that the bentonite will vary in which cation it exchanges based on the mineralogy that it predominatly surrounded by. I expect it to be mostly Ca rich, based on the abundant sandstones in the region. I would also expect the sorting and rounding to be very well rounded and well sorted. I am comparing the crystal morphology and the mineralogy to the articles that we have found where other layers of bentonite are located. I am expecting the depostitional enviroment to play a major role in our results. With the help of Preston Larson I will be using the Scanning Electron Microscope to looking at the grain size, sorting, chemical anaylsis, and crystal morphology. I am also stating that there will not be fossils present in the layers of bentonite, but they should be found in the layers surrounding it. I am hoping to take sample and be able to test by looking in a hand sample.
There is news that an asteroid will just barely miss earth in the coming day, but now a meteorite has hit Earth! The meteorite hit in Russia February 15 and is responsible for injuring up to 500 people and a majority of those were sent to the hospital (MET , SITE). Even though there are objects that do make it through Earth’s atmosphere from space they are usually extremely small by the time they land.
Scientists have begun taking samples were individuals think they meteorite may have fallen. The one major site that is being investigated is an ice hole that is six meters in diameter and shows signs of alteration from what could be a meteorite (SITE). Scientists are stating that is was moving near 30km/s and that it could be related to the asterioid, but more information is still coming in to determine all the specifics (SITE).
During the past week I have spent time practicing field methods that will be used during the spring break trip to Lee’s Ferry. I hope to use some of the mapping techniques on our individual project if applicable.
My main focus this week was looking at the properties of bentonite clay to further understand its significance. By searching quickly it was interesting to find that bentonite is used largely for medicinal purposes; including digestive symptoms, morning sickness, and used on the skin ( Medicinal). This discovery was not to surprising since kaolinite is used in many health products as well. However, kaolinite and bentonite clays are in two different groups. The bentonite clay is a smectite and is specifically referred to an impure form of montmorillinite (Clay). Smectite clays are highly expandable and tend to form in the tropical regions where clays form with abundant aluminium (laterite soils), but can also be found in cool and dry regions (Book). With the abundant information on the crystal structure of bentonite and the location it is typically found, I am going to look at the paleoclimate of the region we are looking at to determine what the conditions were like when the ash was deposited. It is still a little confusing how the volcanic ash is a clay, but it is starting to become more clear.
The paleoclimate data should be easy to find. The ash layers were mainly deposited in periodic episodes during the Mesoizoic (Age). I found an article by the USGS that describes the depositional and climatic settings that will help me continue with this subject.
A cute video of the geologic timescale! Enjoy!
Bentonite is one of the distinctive layers found in the Chinle formation. The layers stand out due to their coloring, which makes them more unique ( NPS ). The bentonitic is a clay layer of volcanic ash that was deposited during the Chinle formation about 250 Ma, but there are stronger evidence to show that it is found in the Petrified Wood Member and Blue Mesa Member, as well as more research currently being conducted to find out more locations (NPS, Blue Mesa). According to the information found from Blue Mesa, there is evidence of fossils in the Chinle formation, but they are not present in the benonite layers in Arizona where their research was conducted. I would like to investigate more research and look into samples at the Lee’s Ferry site to compare. In any case researching all possible angles this topic will help us compare the benonite at the Lee’s Ferry site and at other specified sites that have been previously studied.
The Soloman Islands were hit by a large, 8.0, earthquake today. The earthquake triggered a tsunami locally, which wiped out towns in the Soloman Islands and killed a small number of people. Thankfully, there are warning systems in place that notified other communities that could have been in the path of the tsunami (CNN). My heart goes out to the families that lost loved ones and the families that have lost their homes.
There are still fears that are associated with large earth quakes and more information is coming in on the specifics of the quake. According to the USGS, the depth was changed to near 28.7 km from a more shallow depth previously recorded in the day (CNN, USGS). The earthquake was recorded at 10.738 degrees S and 165.138 E, which is on the westeren edge of the Soloman Islands (USGS).
After further discussion on our topic of bentonite, I would like to look at the volcanic ash layer and make a stratigraphic column of a few layers below and above the bentonite. More research will be conducted to compare what is found at the Lee’s Ferry site and what is found in a neighboring region, as suggested by Jefferson Chang. Samples will be brought back to the lab for analysis after the spring break trip. Based on photos that I have found through research, it appears the layers will exposed very well. Another aspect that I will be focusing on heavily will be the fossils found in the sampling site compared to other regions and the environments.