Stamp Sands
Deltas can’t form easily in the Big Lake. The currents disturb and redistribute the sediments that would be stable in a calm lake.

Ontonagon River Mouth

Isle Royale Sands, Houghton

Pilgrim River Delta

Traprock River Delta
C & H Conglomerate Stamp Sands, Lake Linden

Torch Lake

Sturgeon River Delta

Below, in Portage Lake is the “Isle Royale” Sands, waste from mines SW of Houghton, and a stamp mill located just east of Houghton on US 41.  The stamp sand here is located just west of the Pilgrim River delta. It was toxic to all plants, but now has been revegetated and engineered, including a man made wetland.

Freda Sands
Freda Mill
Gravereat River tannic acid plume
North Entry

Stamp Sands are mining waste materials which have been dumped into local rivers and lakes, including Lake Superior.  They contain toxic materials and contaminate the water and change the landscape. There are many interesting sites to visit (see map at right, and links to each).

Stamp Sands kml


Stamp Sands are unstable, highly mobile features that spread rapidly in Lake Superior. In inland lakes they are preserved for decades and form features that resemble river deltas. Below the Traprock River delta butts up against a stamp sand fan at Lake Linden.

South of Houghton, at Chassell, is the Sturgeon River delta,a spectacular natural wetland area which is an important bird and plant habitat. South of the delta, the straight part of the waterway are engineered by dredging to allow ships to use the waterway from ports in the Greaat Lakes and beyond.

The Freda Sands are a highly mobile stamp sand which came from the Freda and Redridge Mills and are being moved both East and West by Lake Superior currents and waves.