Eskers as mineral exploration tools

Eskers are commonly sampled for indicator minerals during drift prospecting campaigns on the Precambrian Shield. However, a literature review reveals that indicator mineral dispersal in esker sedimentary systems is poorly understood. As a result, exploration companies lacking their own proprietary knowledge are left with little basis for understanding how to collect esker samples or how to interpret esker data. Based on the literature review, and drawing insights from a broader body of literature on modern glaciers, laboratory experiments, and gravel-bed streams, a preliminary conceptual framework for esker sedimentary systems is established to address these issues. A research strategy is then outlined, one whose objective is to fill knowledge gaps and, in doing so, improve the effectiveness of mineral exploration in glaciated terrain.

► Esker sampling is a proven exploration method that has led to the discovery of mineral deposits.
► Sand-sized heavy minerals are more highly concentrated in eskers than in the adjacent till.
► Dispersal trains in eskers can be shifted downflow relative to till by several km to a maximum of several tens of km.
► Stream-sampling guidelines are often followed, but may not be optimal.
► Improving the use of eskers as exploration tools will hinge on a better understanding of how eskers form.