Every Rock Has A Story - Komatiite

This komatiite from southern Africa is one the Earth’s oldest volcanic rocks. It formed from extremely hot lava (~1600° C) 3.6 billion years ago. It is dominated Fe & Mg rich silicate minerals derived from melting of the mantle. Ultramafic volcanic rocks like these are largely restricted to the Archean Eon 2.5 to 4 billion years ago. Their chemistry suggests that the earth was much hotter during its early history – with the mantle being roughly 500°C hotter than today. The elongate crystals of Olivine and Pyroxene, create a fabric called spinifex texture – indicating rapid quenching of the lava in water.