A Geoconservation perspective on the trace fossil record associated with the end – Ordovician mass extinction and glaciation in the Welsh Basin

In this thesis I have illustrated the value of our geological heritage and geodiversity by focussing on a particular detailed aspect of the geological and palaeontological record, i.e. the trace fossil record associated with the end Ordovician (Hirnantian) global glaciation and extinction episode. The major elements of this work that are new are: • a significantly improved understanding of the nature of the soft sediment deformation, and in particular the role of “debrites” as basal landslide decollements in the Lower Palaozic Llangrannog rock succession of West Wales, • a much more detailed description of the trace fossil ichnocoenose present in the Llangrannog succession than has previously been published • an improved understanding of the nature of the ecological perturbation associated with the Hirnantian (Late Ordovician) Glacial “ice-house”, and the apparent role of an opportunistic soft body fauna in filling ecological niches vacated as a consequence of the associated extinction. • Considerable thought has been given to the question of how to value abiotic nature, and it is argued that the methods of conservation valuation associated with “Geosystem services” and in particular “Natural Capital” hold considerable potential for the Geoconservation community to engage with the public and with policy makers. • As a direct result of this research, two formal proposals have been put forward for new RIGS sites, together with a new geological SSSI