Natural diamonds usually form 100 and fifty– hundred km below the floor of the earth. Diamond formation does no longer upward thrust up everywhere at those depths, however simplest underneath the oldest continents that have been strong for billions of years; those areas are known as cratons (see determine 2 in Summer 2018 Diamonds from the Deep). This is due to the fact those vintage cratons all have thick continental roots with cool temperature profiles conducive to diamond formation that geologists term “continental lithospheric mantle.” Diamonds that shape interior the ones continental roots are known as lithospheric diamonds and are carried as masses due to the fact the floor of the earth via unusual volcanic eruptions known as kimberlites.
Other diamonds shape an lousy lot deeper in the earth, in sublithospheric regions of the mantle, underneath the ones continental roots. So-referred to as superdeep diamonds form at depths a awesome deal more than two hundred km, in areas of the mantle referred to as the transition area (410 to 660 km below the earth’s floor) and reduce mantle (>660 km). After formation they may be transported to shallower depths inside the mantle, in all likelihood through mantle convection cells, after which furthermore delivered to the floor by means of the usage of way of critical to form diamonds and the pass decrease back of diamonds to the floor. Ocean ground is thrust deep into the mantle thru the machine known as subduction and consists of diamond-forming fluids in its seawater-altered minerals and rocks. Mantle convection pass lower decrease lower back go with the flow moreover reasons warmth mantle to upward thrust to shallower degrees and soften, producing the kimberlites that supply diamonds to the ground.