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| December 2023 |
The first meteorite in Montana Learning Center’s meteorite collection has been classified and added to The Meteoritical Society’s official list of all meteorites
Montana Learning Center at Canyon Ferry Lake (MLC) is proud to announce that the first meteorite in its meteorite collection has been formally classified by academic researchers and added to The Meteoritical Society’s official list of all known meteorites. The official name of the meteorite is “Northwest Africa 15913”; its work name is “MLC01.”
The meteorite was analyzed by Dr. Anthony J. Irving of the University of Washington in Seattle and Dr. Joseph S. Boesenberg of Brown University, and has been officially classified as a Type 3 carbonaceous chondrite meteorite of the oxidized subgroup (summarized as meteorite classification CVox3). MLC01 is one of only 33 CVox3 meteorites ever discovered. That’s just 0.042% of all classified meteorites!
A meteoroid is a small, rocky or metallic object launched into space by an impact on its parent asteroid’s body.
When a meteoroid is caught in Earth’s gravitational field and descends through Earth’s atmosphere, its outermost regions are heated to very high temperatures, while its interior remains cold. These high temperatures cause the meteoroid’s outer portions to melt and vaporize, resulting in the emission of very bright light, visible with the naked eye. The resulting brightly lit object speeding across our skies is referred to as a meteor.
If the meteoroid isn’t completely destroyed during its descent through Earth’s atmosphere, and some portion of it lands on Earth, the part that lands on Earth is called a meteorite.
A CVox3 meteorite is a mostly stony (non-metallic) meteorite containing a relatively high proportion of carbon (up to 3%) and some magnetite (a form of iron oxide). This type of meteorite is thought to be derived from small to medium primitive asteroids that were formed when various types of dust and small grains in the early Solar System grew together (“accreted”).
The asteroids from which CVox3 meteorites come are much older than Earth and likely were formed over 4.54 billion years ago. These asteroids were formed or accreted from the nebular disk around the early Sun (a nebula is a giant cloud of dust and gas in space). Type 3 chondrites — like MLC01 — have experienced relatively little heating within their parent asteroid since the parent was formed.
In addition to being one of only 33 meteorites of its type ever found, the MLC01 meteorite also exhibits a relatively low degree of weathering, which means it was found relatively quickly after it fell to Earth. As is true of many meteorites, especially those recovered in Northwest Africa, the MLC01 meteorite was originally found by a nomad in the Sahara Desert.
The MLC01 meteorite contains spherical lighter-colored objects of various sizes, which are known as “chondrules.” Chondrules in a meteorite are the result of the flash melting and then very rapid cooling (“quenching”) of dust particles and/or dust clusters within the solar nebula, followed by the accretion of these cooled melt droplets into the meteorite’s parent asteroid. Also present in the MLC01 meteorite are irregularly shaped, whitish, very fine-grained calcium and aluminum rich inclusions (CAI), which originally condensed from gas within the solar nebula. The darker parts of the meteorite are fine-grained rock consisting of a variety of silicate and oxide minerals, including several minerals that are among the most prevalent minerals found in the Earth’s crust and upper mantle.
The official classification listing for the MLC01 meteorite can be found at https://www.lpi.usra.edu/meteor/metbull.php?code=79554.
MLC thanks Dr. Anthony J. Irving, one of the academic researchers who analyzed and officially classified the MLC01 meteorite, for his in-depth review of this article for scientific accuracy. MLC also thanks Craig Zlimen, who brought this meteorite to the attention of MLC’s Executive Director.
Montana Learning Center at Canyon Ferry Lake, located just outside of Helena, offers a variety of STEM-focused youth summer camps, teacher learning opportunities, NASA educational and outreach programs for middle and high school students in partnership with Montana State University, and the State’s premier astronomy program, featuring the largest and most advanced public-use telescopes in Montana.
MLC’s meteorite is officially known as Northwest Africa 15913.
This back-scattered electron image shows typical features of NWA 15913: darker chondrules within a lighter gray (more iron-rich) matrix and very bright grains of magnetite.
At the lower left of the image is a one-millimeter-long scale bar.