A study of 230 samples of porcelanite and siliceous mudstone from a single stratigraphic section containing all three silica phases in the Sisquoc and Monterey formations, Casmalia Hills, California, tested established models of silica diagenesis. Analysis of composition, silica phase, and d 101-spacing using combined EDS/XRF and XRD documented a broad distribution of opal-CT d101-spacing values rather than a linear progression for any particular compositional range predicted by prior studies. The data from this thesis study strongly suggest that other variables (e.g., carbonate, organic matter) besides burial depth/temperature and normalized silica:detritus ratios are critical to diagenetic ordering and that the opal-CT d101 -spacing and silica content of a single sample cannot be used as a geothermometer. Instead, the maximum opal-CT d101-spacing in a set of samples for any normalized silica:detritus ratio in a stratigraphic interval may be useful to determine the minimum temperature or maximum burial depth reached prior to tectonic uplift.
|Advisor:||Behl, Richard J.|
|Commitee:||Holk, Gregory, Hummel, Greg|
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 54/01M(E), Masters Abstracts International|
|Subjects:||Geology, Sedimentary Geology, Geochemistry|
|Keywords:||Casmalia hills, D101-spacing, Monterey formation, Santa maria basin, Silica diagenesis, opal-CT|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be