Brittle versus ductile carbonate behavior (dolomite vs. limestone)

[coreman]

Does anyone have any references which will describe the term &quot;brittleness&quot; in rock mechanics terms?&nbsp;&nbsp;I'm trying to get a handle on the relative &quot;brittleness&quot; of a dolomite versus a limestone.&nbsp;&nbsp;This is specifically in reference to the formation of fractured super K (permeability) in thin-bedded dolomites, sandwiched between limestones.&nbsp;&nbsp;The theory is that the dolomites are more brittle then the limestone, and tectonic events which deform (i.e., ductile behavior) the limestone will fracture the dolomite (i.e., brittle behavior), creating super-K intervals.&nbsp;&nbsp;I've tried a few of the available web sites for civil engineering, but haven't found any good answers yet.&nbsp;&nbsp;<br><br>Any ideas, short of actually measuring the properties?&nbsp;&nbsp;.&nbsp;&nbsp;If we did measure the properties, what would be the parameters which would define the term &quot;brittle&quot;.&nbsp;&nbsp;I know the common stuff like using the triaxial yield points versus the failure point to evaluate the ductile versus brittle failure, but are there any guide lines, general references or studies which define a given rock type as more or less “brittle”?<br><br>Do you have a reference to the experimental work with dolomite and limestone?&nbsp;&nbsp;or any other associated references I can read through?&nbsp;&nbsp;The major problem will be that there is generally no unfractured core recovery from these dolomite intervals,&nbsp;&nbsp;so I don't think we could get a decent set of plugs to look at.&nbsp;&nbsp;I can show that this has happened by looking at the core, and postulate that the differences in &quot;brittle vs. ductile&quot; behavior is the root cause, but that doesn't give the engineering gang any hard laboratory data.<br><br><br>Regards,<br><br>Jack D. Lynn<br>