Introduction to meteorites
This map shows the locations of the meteorites found in Canada. Red dots
indicate meteorites recovered soon after their fall was observed ('Falls').
Green dots locate specimen discovered by chance many years after they fell
to earth, possibly unnoticed ('Finds'). A number of interesting features
are apparent: the surprisingly low total number of meteorites for a country
of the size of Canada undoubtedly reflects the sparse population and the
relatively small proportion of worked land. Thus finds and falls are concentrated
in more populated regions, the farmlands of the prairies, the St. Lawrence
lowlands and southern Ontario. It is noteworthy that although a few meteorites
have been found in the enormous areas of the Yukon and Northwest Territories,
not a single fall has been recovered. Even when observations pinpoint the
area of a fall in such a region very accurately, recovery from bush country
is more difficult than the search for the proverbial needle in a haystack.
The three principal categories of meteorites are stony, stony irons and irons. Stony meteorites are divided further into chondrites and achondrites, principally on the presence or absence of chrondrules (spherical bodies up to a few mm in diameter). To date over 200 different minerals have been found in meteorites and this number is increasing. Some only exist in trace amounts, however, or in rare meteorite types. With the exception of the forms of iron, the other common minerals in meteorites are also found in terrestrial rocks.
Orthopyroxene - (Mg,Fe)SiO3
Diopside - (Mg,Fe)CaSi2O6
Olivine - (Mg,Fe)2SiO4
Serpentine - (Mg,Fe)6Si4O10(OH)8
Plagioclase - (Ca,Na)(Al,Si)4O8
Kamacite - alpha Fe,Ni 4-7% Ni
Taenite - gamma Fe,Ni 30-60% Ni