Triangle Motif---dipping layers
 

The Keweenaw features an assymetrical profile, with noticeable slopes.  If you once notice it, you see it everywhere. Map it!

On Isle Royale the rocks are the same, and you find the same triangular motif---but the layers dip the other way. This dipping of layers has a big influence on every day life, landscapes, roads, water supplies, shorelines, harbors and many other things.

Questions to explore: Once you know about the tilting of layers that is fundamental to the Keweenaw and Isle Royale--what does it lead to? Why does this structure concern us?  How can we use this information?

How does the dipping rock affect life in Houghton and Hancock, which are built right on them?  How does it affect the Peninsula?

Amygdaloidal Minerals of Michigan’s Keweenaw Peninsula Lavas

The most obvious properties of the amygdule minerals can be used to identify them. The sport of mineral collecting is done by many visitors who use this kind of mineral Identification to find local treasures, including agates and datolites.

 

What’s next?  After mastering the mineral identifications in the boulders, students can also look at amygdaloidal minerals to study the order that minerals deposited in those vesicles, what mineralogists call paragenesis.