Finding Small Iron Meteorites With Gold Bug 2

[walkerrj]

If you do an internet search for the words "cotopaxi meteorite" you should come up with several news articles/photos of our Meteorite.  It was an iron/nickel type and weighed 243 grams and was about the size of a large lemon.  The Norton books mentioned by fredmason are excellent.  

[Paleomanjim]

I'll second that....  "Rocks from Space" by Richard Norton is the best place to begin to learn about meteorites. It inspired me to start searching, but I am lucky because we have several meteorite strewn fields out here in the south west. Strewn fields were created by much larger falls, like the one last year in Russia that produced thousands of small meteorites.  Though rare, there must me many strewn fields, including Alaska, waiting to be discovered.

   It took me 3 trips of several days each to find my first meteorite several years ago. The first problem (if using a metal detector) is learning the distinctive sound a meteorite gives compared to a hot rock. I am sure I passed my detector over many meteorites thinking it was another hot rock before I finally learned that distinctive sound. What helped for me was to purchase several chondrite meteorites on Ebay and study them often. Some NWA (North West Africa) meteorites can be purchased for less than $20 and are great study pieces. Purchase only from dealers though and avoid Chinese meteorites (many are fakes). I bought a 45 gram NWA "H" type chondrite for $15 early on and used it as a throw down for my detector to zero in on the correct sound. That helped a lot.  It had nice fusion crust, another feature you want on a study piece. I also picked up some 5 grammers and ground windows on them to be able to see what the inside of a chondrite should look like (visible metal flakes and possible chondrules).  Without the study pieces it is very hard for a beginner to be able to tell the difference between an ordinary rock and a meteorite, as many ordinary rocks will stick to a magnet and some (like magnetite) can even appear to have fusion crust. Learn how to do a streak test, red, grey or black streaks are usually meteor wrongs. 

   I have never found a "cold find" although I have made several trips to search for one. I have tried both searching with a metal detector as well as just a magnet stick. It takes an incredible amount of patience to swing a detector for hours on end in the open desert knowing that the odds of a find are extremely thin.  And yet it is also probably likely that every square mile of desert (and any land for that matter) has several meteorites on or close to the surface! I usually use a magnet cane for cold find searching now and try to use my eyes for the right "look". A lot more ground can be covered and for me it is just more enjoyable. I am guessing most cold finds were found with a magnet stick, not sure though. 

   Hunting in Alaska would be pretty tough, especially near Anchorage and the population centers because of the forests. That would probably require a detector to search. The tundra areas would probably be best, many Mammoth tusks have been found in the Tundra in Alaska and especially Siberia. Ice fields and glaciers produce thousands of visible meteorites but mostly from Antarctica which has unique processes. Each year teams of searchers from many countries search Antarctica. Meteorites from falls thousands of years ago are found there in good numbers as they are carried down hill by the "conveyor belt" of ice toward the sea. In specific areas the ice must move around or over the land beneath, which exposes it to the wind, eroding the ice and leaving the meteorite on the surface. Maybe similar conditions exist in Alaska....I dont know.

   Hope you give it a try. Every "cold" find" that is classified is a benefit to science and the understanding of how planets came to be, as well as us for that matter!.......jim

[sjmpainter]

Good info guy`s. I can tell I will have to read up on this as I`m already at a loss with some of this info.

But I have to ask, what is a cold find?

[Paleomanjim]

A cold find is any new meteorite found that is not associated with a known strewn field or known fall.....I think

[fredmason]

yes, and was not a witnessed fall...which would also be a subset of the known-fall category...

fred