Dolomites epigenetic

Gregg J.M. (1985) Regional epigenetic dolomitization in the Bonneterre dolomite (Cambrian), southeastern Missouri. Geology 13, 503-506. 

Shelton, K. L., Bauer, R. M., and Gregg, J. M., 1993, Fluid-inclusion studies ofregionaUy extensive epigenetic dolomites, Bonneterre Dolomite (Cambrian), southeast Missouri Evidence of multiple fluids during dolomitization and lead-zinc mineralization Geological Society of America Bulletin, v. 105, no. 7, p. 972-978. 

Gregg, J.M. Sibley, D.F. (1984) Epigenetic dolomitization and the origin of xenotopic dolomite texture. J. sediment. Petrol., 54, 908-931. 

Shelton et al. (1992) reported data from 476 fluid inclusions from various types of epigenetic dolomites. Because it was unclear which data points refer to saddle dolomites only the range of values was regarded here. 

Fig. 1. (Continued) (E) Coarse-crystalline saddle dolomite replacing host dolomicrospar. Note optical zoning of dolospar due to variable inclusion densities. Triassic limestone with epigenetic dolomite and sphalerite-galena-fluorite mineralization. Eastern Alps (Wanneck area, Tyrol). Scale bar = 500 pm. (F) Host carbonate rock completely replaced by non-planar dolospar. Note that about half of the crystals in the field of view show regularly curved crystal boundaries and/or incipient sweeping extinction, i.e. saddle dolomite. Triassic limestone with epigenetic dolomite and sphalerite-galena-fluorite mineralization. Eastern Alps (Wanneck area, Tyrol). Scale bar = 500 pm. (See also colour Plate 1, facing p. 446.)...

The range of values in Shelton et al. (1992) include data from saddle dolomite and from other epigenetic dolomite varieties. 

Fig. 11. Frequency histogram of final melting temperatures of primary fluid inclusions in saddle dolomite. Data from Coniglio Williams-Jones (1992) are mostly from inclusions of secondary or indeterminate origin and are shown for comparison. Horizontal arrows indicate literature sources that reported a range of values only. The upper x axis gives an expression of the measured temperatures as wt% NaCl eq., based on a pure H20-NaCl system (after Bodnar, 1993). The composition of seawater is indicated by the vertical dashed line (Tn, = -2.1 °C). The range of values in Shelton et al. (1992) include data from saddle dolomite and from other epigenetic dolomite varieties.

SucHY, V., Rozkosny, I., Zak, K. Francu, j. (1996) Epigenetic dolomitization of the Pn doli formation (Upper Silurian), the Bafrandian basin, Czech Republic implications for burial history of Lower Paleozoic strata. Geot. Rundschau, 85, 264-277. 

Mountains, USA. Scale bar = 500 pm. (D) Void-filling coarse-crystalline saddle dolomite postdating authigenic quartz. Triassic limestone with epigenetic dolomite and sphalerite-galena-fluorite mineralization. Eastern Alps (Wanneck area, Tyrol). Scale bar= 500 pm. 

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