Thursday, May 1, 2014

Highlights—Squeezing for Dolomite

Despite considerable effort, the origin(s) of dolomite have remained enigmatic for generations. To explore dolomitization in the Oligocene-Miocene chalks of Barbados, Machel et al. integrate field mapping, petrography, stable isotopes, XRD, and Sr isotopes. The results are interpreted to reveal that the cause of dolomitization in the chalk is similar (if not identical) to dolomite in Pleistocene carbonates at other locations on the island, driven by fluid expulsion from the underlying accretionary prism. The diagenetic history reveals that the Barbados accretionary wedge has undergone a prolonged history of compression, with concomitant expulsion of fluids, that has varied through time and space.  Although dolomitization can result from fluid expulsion in an accretionary prism setting, regionally extensive, pervasive dolomitization is not to be expected from this dolomitizing process.

Episodic fluid flow and dolomitization bymethane-bearing pore water of marine parentage in an accretionary prism setting, Barbados, West Indies by Hans G. Machel, Jonathan B. Sumrall, Patricia N. Kambesis, Joan R. Mylroie, John E. Mylroie, and Michael J. Lace

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