YOU SHOULD PULL OFF THE ROAD AS FAR AS YOU CAN AS THIS AREA HAS A POSTED SPEED OF 65 AND HEAVY TRAFFIC AS WELL AS AN ON RAMP (SOUTHBOUND)
The dark gray rock you see here is the BIWABIK IRON FORMATION. Biwabik is a Native American word meaning “fragment of iron.” It is one of the world’s major iron-formations and the largest in the USA at 200-750 Ft. thick and running almost 100 miles from Lake Pokegama to the West, to Birch Lake near Ely, MN. The layered bedding was created by sediment being deposited in an ancient sea about 1900+ million years ago.
Since the first explorers came to NE Minnesota it has been know that you can’t always trust your compass to give you the correct direction when you are in the woods. This earth cache will give you an example of what happens and also will tie this geological anomaly to the extraction of TACONITE which is the life blood of the Iron Range today.
All the iron ore produced on the Mesabi Range originally was high-grade natural ore. By 1955, the mines were being depleted and so a process was developed mainly by Edward W. Davis at the University of Minnesota to extract magnetite (Fe3-O4) from low grade taconite ore known as the TACONITE PROCESS. The first time the word TACONITE was used, was to describe the BIWABIK IRON FORMATION.
The rock is crushed to a fine powder and the magnetite is removed with magnets. The powder is then formed into marble-sized pellets for ease of transportation to the steel mills.
To get credit for this cache – email me the answer to the 2 following questions:
1. Using a TRADITIONAL MAGNETIC NEEDLE COMPASS, is the NORTH or SOUTH needle attracted to the rock formation?
2.By looking at the bedding in the rock, and using your compass, toward which compass direction are the beds dipping?
CREDITS: Roadside Geology of MN- Ojakangas;Minnesota's Geology- Ojakangas and Matsch;Vol.55-Part2-Field Trip Guidebook 2009- Lake Superior Institute of Geology.