But why is Haute-Vienne a gold-producing region? You have to go back a long way to understand. 450 million years ago, the world map looked very different from today. The Earth has, to put it simply, two large continents. At the location of the Massif Central, there are no meadows, forests and villages. There is an ocean.
Rocks with gold-bearing quartz veins.
Let's speed up a little (and even a lot), since all this happens over tens of millions of years, to discover another face of the same places, modeled by plate tectonics. It is a mountain that now rises where the ocean used to be. A mountain comparable to the Himalayan range, whose high peaks will disappear over time, leaving rocks that were initially at depth exposed. Rocks with gold-bearing quartz veins.
Rifts where gold is found
In these old crystalline massifs which were formed more than 300 million years ago, in certain places, the collision of the plates created faults. It is in some of these faults that we find gold, but not only gold. The molten rocks were, depending on the location, loaded with ores that were present at depth: iron, gold or copper, for example.
12 and 15 grams of gold per ton in Haute-Vienne
The gold content of the gold-bearing sectors of Haute-Vienne is on average between 12 and 15 grams of gold per tonne. The world average content is 4 grams per tonne. The large deposits are located in Australia, China and Russia.
There are several stones with flakes, but there is only one of gold-bearing quartz. It was formed about 300 million years ago and it's gray, because where you find gold, you also find arsenic.
