| Once again in the
Minnesota
River valley we can find exposed bedrock. In this case it is in
the
city of Morton at the junctions of US Highway 71 and MN Highway
19.
I've driven within two blocks of this site for at least 15 years without knowing about it. The rock quarry is one block north of the old Morton High School, two blocks north of Highway 19, one block east of the intersection of Highway 71. The second stop of this leg is at Alexander Ramsey Park in Redwood Falls. |
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| These photos were
all taken
within a few yards of each other in an old rock quarry. The
quarry
is a short walk from the road on a well worn path. When I was
there
for these photos a few young folks were swimming in the pit left by the
quarry.
Morton Gneiss is one of the oldest rocks in Minnesota at about 3.6 billion years. Actually the rock is a migmatite (A mixed metamorphic rock consisting of a schist or gneissose component, and a granitic component forming layers or pods. Migmatite may approach granite in composition. A coarse grained rock with a granular texture, it often shows banding like gneiss formed in areas of high-grade metamorphism. (1)). In these samples it is easy to see the folding and the granitic structures. |
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1. Pellant, Chris Rocks and Minerals, 1992, p 214
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