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Gao et al. 1996

Gao, G., Dworkin, S.I., Land, L.S. and Elmore, R.D. (1996). Geochemistry of late Ordovician viola limestone, Oklahoma: Implications for marine carbonate mineralogy and isotopic compositions. Journal of Geology 104(3): 359-367.

Late Ordovician (Caradocian) age Viola limestones from the Arbuckle Mountains, Oklahoma, have Sr concentrations from 216 ppm to 3720 ppm (average 1600 ppm), delta(18)O values from -5.1 parts per thousand to -3.1 parts per thousand (PDB), and Sr-87/Sr-86 ratios from 0.70775 to 0.70793. Although textural and chemical evidence indicates that these limestones suffered diagenetic alteration, the elemental and isotopic compositions still reveal important information about the primary marine mineralogy and seawater composition during Late Ordovician time. First, the high Sr concentrations suggest that original Viola sediments were composed mainly of aragonite. Second, the highest delta(18)O value (-3.1 parts per thousand) of the limestones, which is interpreted to be the least altered, constrains the delta(18)O values of seawater to > -1 parts per thousand (SMOW), assuming that ocean temperatures were 27 degrees +/- 5 degrees C. Third, the Sr-87/Sr-86 ratios of Viola limestones probably better represent the Sr-87/Sr-86 ratios of coeval seawater because the ratios from these Sr-rich limestones show less scatter than those of similar-aged samples previously published.

BACKGROUND DATA FILES

	Abstract 1

	Table 1

	Methods

Keywords
phanerozoic time, trace-elements, sr/mg ratios, calcite, brachiopods, seawater, oxygen, sr-87/sr-86, diagenesis, indicators

Journal
Journal of Geology
http://www.journals.uchicago.edu/JG/home.html

Publisher
The University of Chicago Press
Henry Hinds Laboratory
5734 South Elliis Avenue
Chicago, IL 60637
1-773-702-7896
1-773-702-9505
jgeology@geosci.uchicago.edu