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| Meteorite Hunting |
| For several years now I have been hunting for meteorites. I have not found any yet but I am still searching. I use a metal detector that I got from Radio Shack. Metal detectors will detect most meteorites because of their high metal content. Iron and stony-iron meteorites are detected strongest but most chondrites will still register if at close range. If you want to buy a metal detector for meteorite hunting you shouldn't waste money on ones with fancy discrimination bells and whistles because meteorites will be detected as scrap iron so you will have to leave it on all metal anyway. I also use a magnet-on-a-stick purchased from a local hardware store, normally used for picking up nails and small tools from the ground. Since the main metal in meteorites is iron the magnet will stick to them quite strongly. If you want portability you could buy a small hand held magnet but then you will have to bend over everytime you see a rock, which becomes quite tiresome after a while. I was thinking about meteorites one evening (as I do most evenings) and I came up with an interesting idea. Here in Canada there were glaciers covering the ground for about 30,000 years. Many meteorites would have impacted the ice during this time. When the glaciers melted small streams formed and merged into larger and larger streams on the surface of the ice. these streams carried rocks and deposited them in little hills of rocks at the ends of the glaciers. Meteorites may have been carried and deposited with the other rocks. I think the rocks from these hills are used for gravel in gravel roads. I often drag my magnet through gravel roads and a lot of rocks stick. All of them so far have been ordinary rocks with magnetite in them but I might get lucky some day. E-mail me if you have an opinion on my idea. I later found out that a similar idea was proposed by Mark Zalcik and Austin Mardon that involved a process similar to the one taking place in Antarctic glaciers. Another good way to find meteorites is to go to a desert, dry lake bed or some other area without vegitation and use a pair of binoculars to look for any lonely rock in the middle of nothing. About the only explanation for seeing a rock where there are no other rocks is if it fell from space. Iron meteorites stick very strongly to magnets and are easy to recognise because they are extremely heavy for their size and appear dark and metallic. Older iron meteorites will look rusty. Stony-iron meteorites are also very heavy but not quite as heavy is iron meteorites. They stick to magnets and appear partially metallic (or rusty if old). Chondrites will usually stick to magnets and are slightly heavier than an ordinary rock. If a meteorite is fresh it will have a fusion crust, a dark glaze caused by heating when the meteorite enters the atmosphere. If the fusion crust is broken off in any place it usually appears lighter than the rest of the meteorite. If the meteorite is stony and sticks to a magnet it is probably a chondrite. You can determine this by grinding off a small corner and polishing it. If you see little round grains and flecks of metal then it is a chondrite. Achondrites usually do not stick to magnets which is a shame since they are some of the rarest and most scientifically valuable meteorites. |