Man-Made Fulgurites

While working my booth this past weekend in Marquette, a woman from the Rapid River area stopped by.  She told me that three weeks ago a tree fell across the electrical wires in front of her house.  Not only did the live wire start a fire in the grass along the highway, but the live wire continued to arc for a few hours before the power company was able to respond.  Once everything cooled off, the family was surprised to find two streaks across the ground that intertwined.  All along the streaks there were colorful fulgerite tubes showing on the surface.

Since I had to drive to Gwinn today to purchase a rock collection, I continued south to visit the site of the weird "man-made fulgurites."

Below is the remains of the tree that knocked down the power line.

When the power line, which the home owner was told carries 14,000 volts, arced over the two to three hour period -- it created the streaks showing above ground.

All along the streaks there are fulgurite-like tubes sticking up out of the soil.  These are called Lechatelierites.  They are made from amorphous (non crystalline) silica quartz.   Apparently, the current-conducting area around the downed power line continued to expand and glow as electrical current flowed into the ground.  Not only were there rows of the fulgurites, but there were also horizontal structures that spidererd perpendicular from the main lines.  Once power was finally removed, the molten materials solidified into a bubbly, glassy silica rock.

 

Below are a couple of close ups of pieces of the "Fulurites"  laying on top of the surface.  Beads of glassy material were also blasted several feet away from the arching line.

The dirt did not look all that sandy.  I took a sample of the dirt and plan on getting it tested to determine its mineral content.

I acquired two boxes of little pieces.  Below is one of the boxes.

I also purchased a few larger pieces.

Lechatelierite also forms from meteror impacts,