Ultramafic rock but there are ultrapotassic and highly silica-under-saturated rocks with >18% MgO which can be considered "ultramafic". Ultrapotassic, ultramafic igneous rocks such as lamprophyre, lamproite and kimberlite are known to have reached the surface of the Earth. Although no modern eruptions have been observed, analogues are preserved. Most of these rocks occur as dikes, diatremes, lopoliths or laccoliths, and very rarely, intrusions. Most kimberlite and lamproite occurrences occur as volcanic and subvolcanic diatremes and maars; lavas are virtually unknown. Vents of Proterozoic lamproite (Argyle diamond mine), and Cenozoic lamproite (Gaussberg, Antarctica) are known, as are vents of Devonian lamprophyre (Scotland). Kimberlite
Sometimes I Sit and Think, and Sometimes I Just Sit Courtney Barnett was announced as the winner of the 2015 Australian Music Prize award which is given for the best Australian album release of the year. Credits are adapted from liner notes of "Sometimes I Sit and Think, and Sometimes I Just Sit". Musicians Production Sometimes I Sit and Think, and Sometimes I Just Sit Sometimes I Sit and Think, and Sometimes I Just Sit is the debut studio album by Australian indie rock musician Courtney Barnett, released on 20 March 2015. The album received wide acclaim and was ranked as one of the best albums of 2015 by numerous