Every Rock Has A Story - Dolerite

This Dolerite specimen formed from the cooling of a shallow intrusion of magma within rocks below a massive outpouring of basaltic lava in Antarctica around 183 million years ago. It was part of a massive set of eruptions, called a Large Igneous Province, that covered a huge area of Antarctica, South Africa, South America and Australia during the rifting of the supercontinent of Gondwana and the formation of the South Atlantic Ocean basin. Vast quantities of carbon gases released by this event have been linked with changes in ocean chemistry coinciding with a major extinction of marine life during the Mid-Jurassic called the Toracian event. The pits on the surface of this Antarctic specimen come from abrasive wind erosion - very similar to the features seen on the surface of rocks on Mars today – a category of meteorite from Mars called a Shergottite is also very similar to the chemical composition of this rock.