Keith Nicholls gave a very interesting talk based upon the research he is undertaking for his PhD. The focus of his research being the glaciation and subsequent extinction event during the Hirnantian Epoch of the Ordovician Period.
The late Ordovician extinction event is one of the five great extinctions in the geological record and is thought to have occurred in two phases 0.5-1 million years apart. The first phase at the beginning of the Hirnantian was closely correlated with the onset of glaciation due to the increase in the Gondwana ice cap which led to a fall in sea level whilst the second phase is correlated with a decrease in glaciation and subsequent rise in sea level.
His work focuses on paleoecology,sedimentology, sequence stratigraphy and stable isotope studies of the rocks in North wales. Using his research, and that from around the world, it has been shown that there was a large positive 13C excursion which suggests a global disturbance in carbon cycling. Also there was a parallel positive excursion in 18O suggesting evidence of cooling an/or ice sheet growth. Even so this area of research remains controversial.