Keweenaw Fault

A fault is a break in the rocks that make up the Earth’s crust, along which rocks on either side have moved past each other.

The Keweenaw Peninsula is divided into two parts by a huge geological fault. The fault controls the way we live, although many are unaware of it. It is one of many elements of our Geoheritage in the Copper Country and the UP.

The Keweenaw Fault is a major geological structure, a giant thrust fault  It represents slippage of several kilometers, triggered by major continental movements. It is not a threat to our daily safety because the continental movement that drove great earthquakes along the fault is all over with, and hasn’t happened for more than 1 billion years! The impetus for earthquakes is absent.  The zone of weakness is there, but there is nothing driving more slippage.

Well, if the fault isn’t active, why should we care about it? There are good reasons:

1. 1.The fault is a major influence on landscapes. Many of the most beautiful sites (rivers, lakes, waterfalls and more) in the area are at or near the big Fault.  Without the fault there would be no such places. Faults that are associated with the big fault influence many other important landscape features, such as the Portage Channel.
   

2. 2.The fault was the conduit for copper solutions to be transported and concentrated.  Without the faults, no mineral deposits would have occurred.
   

3. 3.The fault raised the copper deposits to levels where men could find them and mine them.  Without the fault, the mines would never have been found or mined!