Days after a meteorite struck Russia and left more than 1,000 injured, University of Wisconsin scientists concluded a study of a meteorite that hit Wisconsin with findings of its complex geological history after three years of investigation.
The Mifflin meteorite, named for the town over which it fell and known to many as the “Mifflin Fireball,” blazed through the skies and struck southwest Wisconsin April 14, 2010. It attracted meteorite collectors from all over the world.
John Valley, UW professor of geoscience and a co-author of the paper, said the study began with meteorite fragments found along the streets, roads and in cornfields that, fortunately, had not been plowed.
“People were very generous … some brought the fragments in to us the next day and within 24 hours we put it through electronic microscopes and started to identify it,” Valley said. “There are still lots of pieces of this meteorite in the woods of Mifflin Township that will never be found.”
Valley said a great amount of geochemical information is available and they believe the meteorite was about one meter in diameter and probably weighed a few tons before it exploded into fragments.
UW scientists have done various types of chemical analyses to understand the complex history behind the Mifflin meteorite.
This meteorite is identified as an L5 chondrite, one of the most common types of meteorites on Earth, according to the study’s first author Noriko Kita.
“L5 chondrites are very interesting,” Valley said. “Geochemistry suggests that they all came from one asteroid.”
Scientists believe there was once a large body in the asteroid belt that probably collided with another asteroid and broke into pieces about 470 million years ago, he said.
The Mifflin meteorite might be one of the pieces floating in the inner solar system and hit the earth three years ago, Valley said. There are probably many more of them, he added.
One hypothesis says the meteorite that struck Wisconsin about 450 million to 470 million years ago and created the Rock Elm complex also belonged to the same parent body as the recent Mifflin meteorite.
The findings of their study will be published in the upcoming issue of the journal Meteoritics and Planetary Science. Valley said the paper’s authorship reflects the degree of international collaboration on the Mifflin meteorite study.
Kita said although they will conclude the study of the Mifflin meteorite with the journal publication, there are still unsolved mysteries and possibilities for continued studies.
“We have some unsolved problems that we identified from our study … we do not completely understand the process,” said Kita. “I hope after publishing the paper, other scientists from all over the world will be interested in this meteorite and continue to study it.”
The UW Geology Museum in Weeks Hall permanently owns two pieces of the meteorite donated to it and has five to 10 pieces on loan on display. These fragments are for science use and cannot be cut up by destructive means, Valley said.
The Department of Geological Science can keep the fragments that are donated for research purposes, which can be cut and made into microscope sections.