Jurassic Argentina

2 March 2016
Geology

At http://phys.org/print375851809.html … Palaeontologists in Argentina have announced the discovery of a major Jurassic fossil bed in Patagonia – four years after it was first discovered. The site spans 60,000 square km and has an amazing diversity of fossils. Most of them were recently exposed by erosion and can be picked up from the surface (which is why scientists were loathe to make a public announcement). The Jurassic landscape is laid bare, it is claimed, one of thermal waters, lakes and streams with plants etc. The fossils, it is said, were preserved 'almost' immediately – within a day. You can even see worm holes, fungi spores and cyanobacteria in the soil.

The site lies a long a mountain range, the Desecualo Massif, and it might be interesting to find out a bit more of the geology.

Over at http://phys.org/print375952343.html … we have dinosaurs again – and a really big one on two bulky legs, the abelisaur. A student at Imperial College in London, Alessandro Chiarenza, found a fossil bone in a drawer at the Museum of Geology and Palaeontology in Palermo in Italy, and was impressed by the size. This started the ball rolling and she was joined by other researchers. It seems Abelisaurs were predatory carnivores with extremely small front limbs and powerful muscular hind limbs. Scientists think they were covered in downy feathers, somewhat like giant ostrich like creatures – but with razor sharp teeth and a bulkier build. The bone was retrieved from a fossil bed in North Africa. In the Jurassic this was a savannah like region criss crossed by rivers, streams, and marshes – quite unlike the modern Sahara.

It was calculated the abelisaurus was 9m in length and weight one and a half tons. Smaller abelisaurs have been found – but this one was huge. It was found in a sedimentary context in an outcrop in Morocco rich in Jurassic remains, with a variety of species that appears to have been laid down in a single dump. Scientists couldn't work out how so many predators were operating in the same neighbourhood but the young researchers have the answer it would seem – harsh and changing geology lumped them all together in a single deposit in Morocco coloquially known as 'Stromer's Riddle' – but riddle is no more.

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