Thin sections of geological samples viewed under cross-polarised light can reveal valuable information about the origin of the rocks they come from.
This helps understand the geological process of the distant past and their relevance to the environment we see today.
This thin section of basaltic dyke from Straumsvola mountain, Antarctica, shows larger crystals of clinopyroxene and olivine in a finer grained matrix of plagioclase. Using mineral data, we have calculated the crystallisation temperature of the magma at 1,300ºC +/- 40ºC indicating elevated mantle temperatures during the Jurassic in Antarctica, which indicate the presence of a mantle plume or heating above ambient mantle temperature.
Dr Teal Riley
British Antarcic Survey