Prospecting Ancient Tectonic Ridges

The ridge is at the center of a spreading zone where magma being erupted through the ridge causes spreading that is usually seafloor; one exception is Iceland where the ridge is exposed on dry land.  A ridge is also the home to “black smokers” that are the surface manifestation of leaching minerals from the oceanic crust.  It is fine metal sulfides that cause the smoke like effects when the hot water cools enough to cause these minerals to precipitate where they are deposited in chimney like structures around the black smoker.

The Kidd Creek Mine in Timmins, Ontario an example of a volcanic massive sulfide deposit.
NOAA

 When these sulfides are deposited they persist for billions of years creating mines that are termed “Volcanogenic Massive Sulfides” (VMS).  Some of the greatest metal sulfide deposits on earth are of this type.  There are many examples of deposits of this type around the world two of them are found in the Abitibi region of  Canada the Horne mine is Rouyn-Noranda, Quebec and the Kidd Creek mine in Timmins, Ontario.