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The AAPG/Datapages Combined Publications Database

CSPG Bulletin

Abstract


Bulletin of Canadian Petroleum Geology
Vol. 12 (1964), No. 4. (December), Pages 922-922

Ordovician Bentonites From Ontario [Abstract]

J. B. B. Orr

Five samples of Ontario Ordovician bentonite were examined by using the techniques of heavy and light mineral separation, X-ray diffraction patterns, zircon studies, and base exchange analysis. The clay fraction of the bentonite consists of a mixed-layer aggregate dominated by illite but with some montmorillonite present. In addition, small amounts of chlorite were noted.

The mineral assemblage indicates that the clay altered from a volcanic glass with the composition of a latite. Similar bentonites in Ordovician strata throughout the eastern United States can be traced along with the Ontario horizons to a volcanic vent in the crystalline region of North Carolina.

Potassium-argon age dating yielded tentative ages of 656 and 654 m.y. on feldspars, and 260 m.y. on volcanic glass. This suggests contamination of feldspar and leakage of argon from the volcanic glass. It is felt that future runs on the remaining extracted argon samples may produce more satisfactory results.

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ACKNOWLEDGMENTS AND ASSOCIATED FOOTNOTES

1959, M.Sc., University of Alberta

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