August 1, 2014.
Nineteen bags of Pleistocene Age river deposited samples were taken from the Cemex Quarry in Fresno, CA. There are three formations in the area, deposited from rivers derived from glaciers, consisting of the Modesto, Riverbank, and Turlock Lake; youngest deposited to oldest respectively.
Phi sizes refer to each of the individual grains diameter, larger sized grains are in the negative spectrum while smaller grains are positive. Each sample has phi size bags that range in sizes from -5 to 4+, excluding phi size -2. For the phi sizes of -3 to -5, each individual rock was measured on its three axis and that data was compiled into an excel sheet. This was to determine the textural maturity of the samples which was derived from a number system for the following categories: roundness, rough/smooth, shiny/dull and grain shape.
QLF ( Quartz, Lithic, and Feldspar) tests were conducted on the phi size 0, -1, and -2. This determines the geochemical weathering and its compositional maturity. The QLF graphs indicate that as the phi size increases the grains become more compositionally mature, consisting of mainly quartz while having minute amounts of lithics and feldspars. Respectively, as phi size decreases the grains become less compositionally mature and consist upwards of 90% lithics.
OSL samples were taken from the quarry. These samples give the exact dating to the given areas sampled from the different formations. Due to the month long process, per sample, these results will be included in future publications of this research.
Geochemistry | Geology | Sedimentology
California State University, Fresno (CSU Fresno)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU)., This material is based upon work supported by the Howard Hughes Medical Institute (HHMI). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of HHMI. This work was administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESAME) and the Fresno State Science and Mathematics Education Center (SMEC) on behalf of the California State University.