A giant millipede kindly provides a scale for a photo of some stromatolites in the Nama group, Namibia. Microbial communities grow upwards towards the light. Each growth phases is cemented by carbonate grains that stick to the sticky EPS substance that the communities produce, forming layered stromatolite columns. The stromatolites pictured above formed 550 million years ago – just as some o ...[Read More]
Friday Photo (82): Wildlife in the Field – Confused Sheep
Each morning when we arrived in the field, hoards of sheep* would come marching over sandstone ridges from miles around to congregate in front of our car. After spending a while thinking we may have established a new animal religion, we realised the poor animals mistook us for their farmer coming to feed them. *We acknowledge that sheep aren’t actually ‘wildlife’! (c) Geology for ...[Read More]
Friday Photo (81): Wildlife in the Field – Glacial Tortoises
A pair of tortoises retreat into their shells in fear as a couple of geologists appear to study the diamictite they are walking over. Clasts visible in the rock below mark melting events at the end of the Gondwana glaciation, 300 million years ago. Deposits like these cover much of southern Gondwana, and can be found today in southern Africa, Antarctica, Australia, India and South America. This se ...[Read More]
Friday Photo (80): Wildlife in the Field – Lizard on Dolomite
A lizard basks on top of a very uncomfortable looking dolomitised grainstone. This dolomitised layer is part of a sequence of platform carbonates that formed 550 million years ago. Only some of the layers are dolomitised, and it is unclear whether the dolomite is primary, or formed secondarily, possibly as a result of Mg-rich fluids flowing along small faults. (c) Geology for Global Development 20 ...[Read More]