The Etches Collection – A National Treasure
Organic rich mudstones of late Jurassic age form the primary source rocks for many of the hydrocarbon accumulations of the Central and Northern North Sea as well as reservoirs as widely distributed as western Siberia, Arabia, the Gulf of Mexico and North America. The Kimmeridge Clay Formation outcrops at a variety of locations around the British Isle and in northern France, but it is undoubtedly best seen on the southern shore of the Isle of Purbeck at the eastern end of the Jurassic Coast, the only natural World Heritage Site in England. For many of us, the Dorset coast has been the location of field trips as students or petroleum geoscientists and engineers, where we have examined the character and distribution of organic-rich mudrocks, depositional and diagenetic carbonates, and the subtle textural and sedimentological features which allow an understanding of the source and sealing potential and more recently the reservoir potential of mudstone successions.
The Kimmeridge Clay in Dorset was deposited some 150 million years ago. At the time, rifting produced a depocentre to the south of an east-west trending high that extended across Purbeck to the Isle of Wight in the east. Fault blocks which defined the high would subsequently form the traps for the oils fields at Wytch Farm and Wareham and folding associated with inversion produced the small Kimmeridge field. During the late Jurassic, the land, possibly as close as a few kilometres to the north of Kimmeridge, was vegetated with tropical ferns and early conifers on which grazed giant sauropods. In the skies were large and small pterosaurs, dragonflies and the first feathered birds. But it is from the Jurassic seas that the greatest variety of fossils has come including Ichthyosaurs, Pliosaurs, fish, rays, arthropods, ammonites, teuthoids and other molluscs.
A lasting memory of trips to the Kimmeridge Clay for many will be the evidence for marine life that can be observed in this formation but, also, the difficulties of extracting and preserving quality fossils. This apparent paucity of collectable fossils is in stark contrast to the prolifically fossiliferous older Jurassic mudstone successions at the western end of the Jurassic Coast around Lyme Regis and Charmouth. However, the science of palaeontology rarely gives up its prizes easily and patience, persistence and perseverance are required to master the subject. Nowhere is this more evident than in the world class collection of fossils from the Kimmeridge Clay made by Steve Etches.
Steve Etches is not a geologist by profession or training, but he has had the great fortune to have lived and worked for much of his life in and around the village of Kimmeridge. Steve started to collect fossils found in the foreshore cut into the cliffs near Kimmeridge in the early 1980’s and over the last 30 years, he has amassed a unique collection of over 2000 vertebrate and invertebrate fossils. Through exquisite curation, Steve has compiled a world class collection of the most extensive and finest fossil specimens found in the Kimmeridge Clay.
The significance of Steve Etches’ collection is brought out by the quality and quantity of the finds as well as detailed records of their stratigraphical positions. The clay-rich, fine grained composition of some of the beds in the Kimmeridge Clay has allowed exquisite preservation of soft body parts rarely preserved elsewhere. The collection includes many species new to science and has significant impact on the understanding of the ecology of the Kimmeridge Clay. The significance of the finds and their importance to science has been recognised through awards from the Palaeontological Association (The Mary Anning Prize, 1993 and 2005), the Geological Society of London (R.H. Worth Prize, 1994) and The Geologists’ Association (The Halstead Medal). In June 2014, Steve Etches received an MBE for services to Palaeontology.
Visit Steve’s Collection on the Purbeck Field Trip on 26-27 September 2015.
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