ABSTRACT

A simple petrographic method is presented to quantify the percent of grain-coat coverage in sandstones. The method involves visually noting whether, at the intersection of a grain boundary and an ocular crosshair, a grain coat (or other grain coating) is present or absent. If a coating is absent at the juncture of the grain boundary and the ocular crosshair, then it can be recorded whether an open pore, a pore-filling cement, or another grain is present at that point. The technique is simple to apply as part of standard point-counting procedures for composition or for grain size. It is much less time consuming, minutes rather than hours, than methods that involve measuring grain perimeters and grain-coat length on SEM images or on thin sections. Computer simulations and comparative measurements on sets of the same samples suggest that they yield results comparable to those techniques. It is less subjective than visual estimates of grain-coat coverage and gives more reproducible results. The mineralogy of the grain coat, its thickness, and its paragenetic relationships to other grain-coating phases can be simultaneously recorded.

You do not currently have access to this article.