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Controlling variables in the transition from a non-organic-rich marine shale to an organic-rich marine shale, Devonian Ohio Shale, north-central Ohio

Dunkel, Caroline Aubrey
http://orcid.org/0000-0002-0541-1779
http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1589752994470939

Abstract Details

2020, Master of Science (MS), Bowling Green State University, Geology.
The accumulation of organic matter in black shales has been heavily debated. Despite the interest in organic-rich sediments (ORS), few studies have focused on the details of the transition between environments of low ORS to high ORS. This study focused on the transition between the Devonian non-organic-rich Olentangy Shale to the overlying organic-rich Ohio Shale in the northern Appalachian Basin. This study consisted of two parts, an in-depth lithofacies analysis and geochemical analysis on a core (2739) located in Erie County in northcentral Ohio. A total of 11 lithofacies and five lithofacies assemblages were identified in the Olentangy Shale and Ohio Shale. Event layers, such as hyperpycnites, are common in the dark colored Huron Shale Member and Cleveland Shale Member of the Ohio Shale. Turbidites are found throughout the Ohio Shale and tempestites are found at the base of the Cleveland Shale Member. A total of 30 samples were collected from the core, 10 of which were used to create thin sections to aid in interpreting the environmental changes between the Olentangy Shale and Ohio Shale. Thin section analysis showed small-scale features, such as basal erosion, inverse and normal grading, and mineral replacement. Samples collected for geochemical analysis were studied for total organic carbon (TOC), mineralogy by X-ray diffraction (XRD), element concentrations by X-ray fluorescence (XRF), and trace elements by inductively-coupled plasma emission spectrometry-mass spectrometry (ICPES-MS). In the transition from the gray Olentangy Shale to black Huron Shale Member, bottom waters became anoxic, TOC increased, and hyperpycnites increased. In the transition from the black Huron Shale Member to the gray Chagrin Shale Member, bottom waters became oxic, TOC decreased, and hyperpycnites decreased. In the transition between the gray Chagrin Shale Member and black Cleveland Shale Member, bottom waters became anoxic, TOC increased, and hyperpycnites increased. In summary, the data suggests that the gray shales were deposited under oxic bottom waters and the black shales were deposited under anoxic bottom waters. In addition, the organic matter in the Devonian Shales is terrestrial sourced. One way of reconciling these observations is to attribute sediment TOC values to sediment dynamics (distributary lobe avulsion) of the Catskill Delta. Time intervals of increased terrestrial organic matter input would result both in high input rates and water column oxygen stress, similar to the “dead zones” of many modern deltas.
James Evans, Ph. D. (Committee Co-Chair)
Jeffrey Snyder, Ph. D. (Committee Co-Chair)
John Farver, Ph. D. (Committee Member)
Angélica Vázquez-Ortega, Ph. D. (Committee Member)
144 p.
Environmental Geology; Geochemistry; Geology
Black Shale; Ohio Shale; Olentangy Shale; Catskill Delta; Devonian; Appalachian Basin; Organic Carbon; Hyperpycnites

Recommended Citations

Citations

  • Dunkel, C. A. (2020). Controlling variables in the transition from a non-organic-rich marine shale to an organic-rich marine shale, Devonian Ohio Shale, north-central Ohio [Master's thesis, Bowling Green State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1589752994470939

    APA Style (7th edition)

  • Dunkel, Caroline. Controlling variables in the transition from a non-organic-rich marine shale to an organic-rich marine shale, Devonian Ohio Shale, north-central Ohio. 2020. Bowling Green State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1589752994470939.

    MLA Style (8th edition)

  • Dunkel, Caroline. "Controlling variables in the transition from a non-organic-rich marine shale to an organic-rich marine shale, Devonian Ohio Shale, north-central Ohio." Master's thesis, Bowling Green State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1589752994470939

    Chicago Manual of Style (17th edition)

bgsu1589752994470939
196
© 2020, some rights reserved.Creative Commons License Controlling variables in the transition from a non-organic-rich marine shale to an organic-rich marine shale, Devonian Ohio Shale, north-central Ohio by Caroline Aubrey Dunkel 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 Bowling Green State University and OhioLINK.