Submit a Picture

Where is My Picture?!

The Queue

Met Name

Met Type

Thin Sections

16.2 grams.   L5

TKW 18 kg. Observed fall 26 March 2003, Cook County, Il, USA.

 

Steve writes:

Just before midnight on March 26, 2003, a bright orange fireball was spotted approaching from the southwest in the sky across Illinois, Indiana, Wisconsin and Ohio; then at approximately 11:50 p.m., hundreds of meteorite fragments showered the village of Park Forest, Illinois (Park Forest is located about 35 miles south of Chicago and was originally designed as a planned community for veterans returning from WWII – although lower now, at the time of the fall, its population was approximately 23,000 people). The event was described as the most densely populated region to be hit by a meteorite shower in modern times. Houses, cars, and a Park Forest fire station were struck, and two streets experienced damage to their asphalt (one meteorite even created a softball-sized hole in one home’s ceiling).

Numerous stones were collected across a 5- by 2-mile strewn field, which had been spread by strong westerly winds over residential neighborhoods and a forest preserve (the smallest pieces were deflected the farthest eastward, while the largest ones – having more momentum – were deflected the least). Collected fragments ranged in size from a few grams to 6.6 pounds. In all, more than 40 pounds of the stone meteorites were recovered.

Park Forest is an L5 ordinary chondrite. Steven Simon (University of Chicago) with seven colleagues from the University of Chicago, the Planetary Studies Foundation, Harper College, Pacific Northwest National Lab, and the Field Museum in Chicago, classified the meteorite and described it as follows:

Most stones are partly to fully fusion-crusted. Some broken faces showed brecciated textures and angular clasts, with cross-cutting dark veins and dark pockets that may be of impact melt origin. Abundant troilite and metal was visible in some broken faces, and while no visible chondrules were seen in the hand sample, chondrules and maskelynite were visible in thin section.

Based on the magnitude of the energy that was released, scientists estimate the size of the Park Forest meteor to have been between 8 and 11 metric tonnes.

The 16.2 gram, partially fusion-crusted piece featured in this post was personally collected by Edwin Thompson of E.T. Meteorites and is one that struck a house on Winslow Street, making it a true “hammer stone” (it shattered when first hitting the street, with pieces ricocheting onto the house, its roof, and a parked car). Photo 1 shows our fragment in a 6 x 5 inch Riker mount display I created many years ago when exhibiting several meteorites at a local rock show (sorry for the poor picture, but with the reflective glass, the photo had to be taken at an angle and then perspective-corrected in software); Photos 2 through 5 offer various views of the fusion-crusted and broken sides.

The 1.5 gram impact melt fragment shown in Photo 6 was also collected on Winslow Street and is somewhat unique in that most Park Forest impact melt lacked any fusion crust. While this particular piece is small (though typical in size compared to some of the smaller pieces of Park Forest collected after the fall), it is distinguishable in that it does contain a small amount of fusion crust on one of its longer surfaces.

Finally, the small vial in Photo 7 contains broken glass collected from the rear window of a car that was impacted by one of the stone fragments (this image offers two perspectives – the front side of the whole bottle next to a 1 cm reference cube, and a magnified view of the back side that better shows the broken glass).