Tolbachik diamonds, history of the discovery, magmatic and mantle formation theories

Author: Demur Merkviladze
Keywords: Tolbachik, diamonds, volcano
Annotation:

Approximately 700 diamond crystals were identified in volcanic rocks of the Tolbachik volcano, Kamchatka, Russia. The formation mecanism of those diamonds is different then we are familiar with, that’s why it brought a big attention from the scientists. Diamond stability zones are usually located in the upper mantle of the Earth estimated to be around 150km below the Earth’s crust. It is an environment with high temperatures and pressure. Normally, diamonds would be part of a foreign rock brought up in a kimberlite eruption. Geologists call these xenoliths, and the diamonds themselves are xenocrysts. However, these Tolbachik diamonds don’t seem to be from xenoliths because there isn’t much other evidence for these chunks of foreign debris in 2012-13 lava. The composition of impurities in the diamonds in elements like nitrogen, fluorine, chlorine and silicon matched the composition of the volcanic gases from Tolbachik. This suggested that they may actually have been forming from the gases being released during the eruption. However, there was one more potential source for these diamonds: people! Some scientists think that microdiamonds could actually just be contamination from drilling or the sampling instruments themselves.