A Geoscience Digital Image Library

TitlePrismatic basalt flow from Montrodeix, Auvergne, France
DescriptionThis picture show the prismatic aspect of a basalt flow. This particular shape is due to the lava cooling down slowly and forming hexagonal convection cells. the border of each cells tends to be cooler than the inside. This phenomenom produce long hexagonal pipe of solidificated basalt. This basalt flow was produced during the Miocene. Now the erosion has cut off all the overlying sediments and the flow can be seen with an inverted relief (on the top of the hill instead of in the bottom of a drainage).
ChronostratigraphyMiocene (20 million years)
LocationFrance ▹ Auvergne. Near Clermont Ferrand. Near Montrodeix.
PhotographerAntoine Bercovici. 2002-09-14.
Key wordsbasalt, volcano, Auvergne
Tech details125 KB. Outcrop. Canon T70, fujifilm 400iso.
GeoDIL number2927