Last Day on the Iron Range...

Monday (Lexy's birthday) was our last day on the Iron Range...a drive day back...we had already celebrated Lex's birthday and presents were waiting when we got back, but we had a few more stops to make after leaving the park...

First up was a short stop at the 36-foot Iron Man statue, a memorial for iron miners in Chisholm...

Then we went to Virginia, to see the highest bridge (just over 200 feet high) in the state of Minnesota.  It crosses the old Roucheleau mine pit and opened in September of 2017.  The Mesabi Trail also uses the bridge, so you can walk out onto the bridge...

The Roucheleau pit merges with other pits to the north and together, ore was mined from these pits for over a hundred years (1893-1997)...

That wind was whipping through the bars on the bridge...

There's an interesting story why the bridge was built.  Back in 1960, Minnesota made an agreement with US Steel to allow them to build a road (US 53) across mine lands.  US Steel maintained the mineral rights under the road.  Per the agreement, if the company needed to mine the land under the road before prior to 1987, the cost to move the road would be on US Steel.  The cost to move the road would fall to the state if it was after 1987.  In about 2010, Cleveland Cliffs (which had taken over the mineral rights from US Steel), notified the state they needed to mine the land under the road.

The problem is that in that area, there are only so many places to put a road without hitting an active mine or old mine pit.  After lots of time and money spent, the decision was made to build the bridge...

 After the bridge, we went to Gilbert to see a 'classic' example of pillowed greenstone.  Greenstone is a metamorphic rock.  It was originally basalt (cooled lava) that was metamorphosed to greenstone.  Pillows, these rounded structures in the greenstone (originally basalt), occur when lava erupts underneath an ocean (think Hawaii today)...

The greenstone is 2.7 billion years old.  How do we know that?  It's science.  The same thing that has confirmed that humans are rapidly warming the Earth's climate by releasing stored CO2 by burning fossil fuels, at a pace that earth systems cannot keep up, causing repercussions that are currently occurring and those are going to get worse.  Yep, science...

One other cool exposure on this 2.7 billion-year-old rock is this small sample of reddish rock.  That rock is part of the Biwabik Iron Formation (currently being mined) that the glaciers could not remove during the last ice ages.  The Biwabik is between 1.8-1.9 billion-years-old.  Meaning at the contact of the two, there is a difference of 800 million years!

See...we're learning...even on a travel day...

It was a good day...