Survival of Micas in a Turbulent Subaqueous Setting
Type of Submission
Poster
Campus Venue
Dixon Ministry Center, Alumni Hall
Location
Cedarville, OH
Start Date
4-10-2013 1:00 PM
End Date
4-10-2013 5:00 PM
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.
Apr 10th, 1:00 PM
Apr 10th, 5:00 PM
Survival of Micas in a Turbulent Subaqueous Setting
Cedarville, OH
Comments
Abstract:
Micas frequently occur in purported eolian sandstones. Other experiments have shown that micas cannot survive eolian conditions, so we wanted to test how long they survive in a turbulent subaqueous setting. We performed an experiment over the course of several months to observe the survival rate of micas in silicate sand carried by turbulent water. The sand used was taken from the Sandhills of South Carolina, and contained mica flakes visible to the naked eye. We constructed a number of apparatuses throughout the course of this experiment. We attempted to churn the sandy water with magnetic stir bars on a magnetic stir plate, but this method ultimately failed due to the intense abrasional nature of the sand. Many variations of this apparatus were attempted. Variations included changing the amount of water, size of magnetic stir bars, speed of the magnetic plates, and volume of the beakers, among other things. We then set up a different apparatus by filling a large glass jar with a mixture of the sand and water. This jar was placed on its side, and rotated at a constant rate by a rock-tumbler motor. Samples were taken frequently. After 50 days, there were still visible pieces of mica in the sand. Mica flakes were visible in the turbulent water as well. The micas do not appear to have eroded very much at all in 50 days. The sand traveled over 950 km in that time. The presence of mica in the sand, after being churned by water for an extended period of time, indicates that turbulent sandy water does not erode mica flakes rapidly. Therefore, micas last considerably longer in subaqueous environments than in eolian environments. This finding is significant because many sandstone formations, which contain abundant micas, have been conventionally interpreted as having been deposited over a long period of time in an eolian setting. The presence of mica in these sandstones suggests that geologists need to reconsider their depositional setting.