Twenty three members attended the last meeting when Bob Loveridge (Visiting Research Fellow University of Portsmouth) entertained us all with a superb talk on the Crato Formation of the Araripe Basin of Brazil. The Araripe Basin is located in a forested cirque in the north central part of the Chapada do Araripe, a large tableland in north-eastern Brazil. The Crato Formation ( Late Aptian in age) is 50-60m thick and is composed of a series of rock types with the basal unit of micro-laminated limestones, the Nova Olinda Member, yielding spectacular fossils which earns the formation its status as a Fossil Konservat Lagerstätte. There is a huge number of fossils all of which are exceptionally preserved and includes insects, arachnids, vertebrates and plants.The Chapada do Araripe is now a UNESCO GeoPark and collecting fossils is illegal without a permit but the area continues to be used for extraction of the limestone for buildings and roads which is leading to it’s destruction.
The fossils are preserved by pyrite/geothite which is thought to be due to pore waters permeating the specimen and envelopment by bacteria which create a covering over the outside of the carcass causing a micro-environment in which mineralisation of tissues can occur i.e. “bacterial sealing”.
The talk was accompanied by superb photographs and SEM pictures of the fossils but also by the escapades that Bob and partners undertook in order to study them.