Possible effects of thermal degradation of organic matter on carbonate paragenesis and fluorite precipitation in Mississippi Valley-type deposits

Research Article| December 01, 1988 Possible effects of thermal degradation of organic matter on carbonate paragenesis and fluorite precipitation in Mississippi Valley-type deposits Charles S. Spirakis; Charles S. Spirakis 1U.S. Geological Survey, Box 25046, Federal Center, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar Allen V. Heyl Allen V. Heyl 1U.S. Geological Survey, Box 25046, Federal Center, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar Author and Article Information Charles S. Spirakis 1U.S. Geological Survey, Box 25046, Federal Center, Denver, Colorado 80225 Allen V. Heyl 1U.S. Geological Survey, Box 25046, Federal Center, Denver, Colorado 80225 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1988) 16 (12): 1117–1120. https://doi.org/10.1130/0091-7613(1988)016<1117:PEOTDO>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Charles S. Spirakis, Allen V. Heyl; Possible effects of thermal degradation of organic matter on carbonate paragenesis and fluorite precipitation in Mississippi Valley-type deposits. Geology 1988;; 16 (12): 1117–1120. doi: https://doi.org/10.1130/0091-7613(1988)016<1117:PEOTDO>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Heating of organic matter to progressively higher temperatures causes a sequence of chemical changes in which carbonate minerals are first dissolved, then precipitated, and then again dissolved. The initial carbonate dissolution is related to the production of organic acids. As heating continues, organic acids begin to decompose to carbon dioxide and methane. This addition of carbon dioxide to a solution with an organic-acid pH buffer causes carbonates to precipitate. Eventually, a temperature is reached at which any remaining organic acids quickly decompose. Addition of carbon dioxide to a solution in which carbonate species rather than organic acids now control the pH lowers the pH and causes renewed carbonate dissolution. The similarity of this sequence to the carbonate paragenesis of Mississippi Valley-type deposits suggests that the carbonate paragenesis in these deposits may be related to the thermal alteration of organic matter. By competing with fluoride for magnesium, bicarbonate ions from decarboxylation off organic matter and dissolution of carbonates may break the MgF+ complex, form the MgHCO3+ complex, and thereby liberate fluoride to trigger the precipitation of fluorite. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.