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Application of X-ray Computed Tomography to Interpreting the Origin and Fossil Content of Siliceous Concretions from the Conasauga Formation (Cambrian) of Georgia and Alabama, USA

Kastigar, Jessica M
http://rave.ohiolink.edu/etdc/view?acc_num=osu1461271051

Abstract Details

2016, Master of Science, Ohio State University, Geological Sciences.
Siliceous concretions from the Conasauga Formation (Cambrian: Drumian to Guzhangian) of Georgia and Alabama, USA, yield a diverse assemblage of body and trace fossils. X-ray computed tomographic (XCT) imaging has been added to standard techniques of analysis including light microscopy, to help determine the early development and fossil content of the concretions. Most of the siliceous concretions show features consistent with biofilm-mediated early diagenesis of siliceous sponges (poriferans), primarily hexactinellids, but perhaps also including some demosponges. Leucon-grade body forms have been identified from images of the networks of canals and the spongocoels within the skeletons, and stauract spicules preserved in the concretions are consistent with a hexactinellid origin for many of the concretions. Some concretions appear to have formed from remobilized biogenic silica and nucleated around other forms of decaying organic matter, including biofilms associated with burrowing traces, fecal matter, and partially decayed remains of other organisms such as hyoliths, trilobites, and cap-shaped fossils. Most concretions probably lithified quickly but some show evidence of a longer-term process of lithification involving multiple generations of early diagenesis. XCT-scans of Holocene and post-Cambrian sponges show remarkable similarities to siliceous concretions from the Conasauga Formation, which supports the conclusion that many of the Conasauga Formation concretions formed around sponge skeletons. XCT-scans of siliceous, calcareous, and other concretions from various Paleozoic localities in North America, South America, and Europe show features similar to those exemplified in Conasauga Formation concretions, which implies similar microorganism-mediated early diagenesis for their origins.
Loren Babcock (Advisor)
Ann Cook (Committee Member)
MaryMegan Daly (Committee Member)
81 p.
Paleontology
Conasauga; concretion; siliceous; hexactinellida; porifera; silica; sponge; XCT; X-ray computed tomography; Cambrian; Guzhangian

Recommended Citations

Citations

  • Kastigar, J. M. (2016). Application of X-ray Computed Tomography to Interpreting the Origin and Fossil Content of Siliceous Concretions from the Conasauga Formation (Cambrian) of Georgia and Alabama, USA [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461271051

    APA Style (7th edition)

  • Kastigar, Jessica. Application of X-ray Computed Tomography to Interpreting the Origin and Fossil Content of Siliceous Concretions from the Conasauga Formation (Cambrian) of Georgia and Alabama, USA. 2016. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1461271051.

    MLA Style (8th edition)

  • Kastigar, Jessica. "Application of X-ray Computed Tomography to Interpreting the Origin and Fossil Content of Siliceous Concretions from the Conasauga Formation (Cambrian) of Georgia and Alabama, USA." Master's thesis, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461271051

    Chicago Manual of Style (17th edition)

osu1461271051
823
© 2016, some rights reserved.Creative Commons License Application of X-ray Computed Tomography to Interpreting the Origin and Fossil Content of Siliceous Concretions from the Conasauga Formation (Cambrian) of Georgia and Alabama, USA by Jessica M Kastigar is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.