--> --> Abstract: Preservation of Intergranular Volume in the Upper Mississippian Kiskatinaw Formation, Alberta, by I. K. Kirkland, I. E. Hutcheon, and H. R. Krouse; #91012 (1992).
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ABSTRACT: Preservation of Intergranular Volume in the Upper Mississippian Kiskatinaw Formation, Alberta

KIRKLAND, IAN K., IAN E. HUTCHEON, and H. ROY KROUSE, University of Calgary, Calgary, Alberta, Canada

Pervasive early cementation of quartz-rich Kiskatinaw basal channel sands by Previous HitanhydriteNext Hit cement prevented reduction of intergranular volume (IGV) by compaction. Several samples from tight streaks in more porous sands have IGV up to 42% with 40% Previous HitanhydriteNext Hit cement. Very early sulfate cementation is indicated by Sulfur 34 values typical for Mississippian marine sulfate averaging 15.66o/oo (CDT). Oxygen 18 values, averaging 14.66o/oo (SMOW), of the sulfate also fit the Oxygen 18-age curve for marine evaporites. Very early cementation also is suggested by fossil moulds of branches whose interiors were rotted out and infilled by Previous HitanhydriteNext Hit before any significant compaction could occur.

The Kiskatinaw was tilted and truncated after deposition allowing entry of fresher waters at the erosional edge, which created porosity through dissolution of Previous HitanhydriteNext Hit cement. Due to the early cementation of IGV, these sands, which experienced maximum burial depths of 2800 to 3800 m, were highly undercompacted and rarely show evidence of pressure solution. During dissolution of Previous HitanhydriteNext Hit, remnant blebs of Previous HitanhydriteNext Hit cement commonly were left behind. IGV within these blebs is usually significantly greater than that in the surrounding rock, which experienced some compaction after removal of Previous HitanhydriteNext Hit. The high quartz content of these sands probably aided preservation of IGV after substantial removal of Previous HitanhydriteNext Hit. Subsequent cementation by quartz and carbonate cements has reduced some of the porosity created by Previous HitanhydriteTop dissolution.

 

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)