Red bed sandstones, being river deposits made up of quartz and feldspar grains that are subrounded to rounded and sorted, make up beds that may have substantial porosity and permeability, so they are aquifers.  Groundwater is filtered through aquifers, and this purifies the water.  Jacobsville water is usually safe. The Jacobsville Aquifer is important on the Keweenaw, with many water wells drilled into it. Since the layers in the Jacobsville are variable and irregular, like the channels of anastomosing rivers, there can be problems with water quality. Uranium is sometimes present in the water.  It comes from mineral grains that weathered out of granitic rocks of the eroded UP mountain ranges. The uranium moves in solution in the ground water and it can deposit uranium in pockets within the sandstone.

Groundwater is purified naturally as it is filtered from flowing through rock pores.

The sand grains in the Jacobsville weathered out of the granite in the UP mountains, and was carried by rivers into the rift valley.

Jim Belote

Bibliography