What is a black smoker in geology ?

Black smoker : definition

Black smokers are chimney-shaped deposits on the ocean floor, spectacular manifestations of hot springs in ocean ridges. These sources emit hot hydrothermal fluids (350°C) rich in metals which react with the sulphates of the sea water and precipitate sulphides which gradually build "chimneys" several meters high, the black smokers, channeling hydrothermal flow.

The "smoke" emerging from these "chimneys" is made up of suspended sulphide particles (mainly pyrite, sphalerite and chalcopyrite) which will essentially (over 97%) disperse in the ocean. These oceanic hot springs are also oases of a very special life.

These are analogous, but not strictly identical, processes that have given rise to polymetallic sulfidic masses since the dawn of time. The study of these black smokers is of prime importance for understanding the processes that gave rise to fossil sulphidic masses.