Thursday 27th March 2014
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.
The next indoor meeting will be held on Wednesday 16th April with a talk by Professor Mike Rosenbaum entitled: Shropshire’s Evolution: highlights of a journey through time.
Sunday 9th March 2014
Our next talk will be on Wednesday the 19th of March, on “The Late Ordovician Ice Age: A Mass Extinction” by speaker Keith Nicholls.
Wednesday 26th February 2014
At the last meeting we heard a superb talk by Dr Geoff Steele on the origins of life.
Even the oldest rocks on Earth have traces of life. They date from the early Archaen, about 3.8 billion years ago. Hence to search for life’s origins we are forced back into the Hadean. The name means “Hell” and it‘s a good description. Huge volcanic eruptions, burning ultraviolet radiation, noxious gases, enormous tides and constant bombardment by meteorites and comets do not sound like a good place to start.
No fossils survive from the Hadean. But the biochemistry of our own cells, and that of all other living organisms, preserves a remarkable record of our earliest times. It has given us a new kind of fossil hunting. In particular the DNA and RNA that store and manipulate our genes can be read like a book, complete with the copying errors and editing errors that tell so much about previous owners. They prove to us that all life on Earth is indeed related, as Charles Darwin proposed, and even allow a reasonable reconstruction of our common ancestor (a simple prokaryote). But where did that come from?
If our quest is the origin of life then we need to think carefully about what we’re looking for. What exactly is life? How is it defined? It seems that replication and metabolism are the minimum requirements, and if they are confined within an enclosed space such as a membrane then that object is perhaps “living”. Could such a thing have formed naturally in Hell? Research suggests that the conditions were right for RNA molecules to form. And they can act as both genes and enzymes giving both replication and metabolism. Hence the simplest life may have begun with just RNA, wrapped in the lipid membranes that form naturally when oil and water are shaken together. And it is astonishing to discover that one of our most basic enzymes, crucial to all modern life, appears to be a living fossil from that time.
The next meeting will be held on Wednesday 19th March when Keith Nicholls will give a talk entitled “The Late Ordovician Ice Age: a mass extinction”
Saturday 8th February 2014
The next indoor meeting will be on Wednesday 19th February where Dr Geoff Steel will give a talk entitled ‘The Origins of Life’.
Thursday 23rd January 2014
Our first meeting of the year was the AGM for which 21 people attended. The AGM was followed by one of Dr Sara Metcalf's super talks. This time on the “Grinshill Fossil”.
On a club field trip to Grinshill quarry in 2013 the owners donated, to Powysland Museum Welshpool, a slab of Tarporley Siltstone containing a series of 19 fossilised footprints and rain drop pits. The talk given by Sara elucidated the current thinking on what formed the prints. Fossils of the herbivorous reptile Rhyncosaurus have previously been found at Grinshill and footprints found have been attributed to that reptile. She went on to say that the slab of Tarporley siltstone was Lower Anisian ( Middle Triassic) in age and would have been laid down in low energy rivers in an arid landscape. Recent re-evaluation of the so-called Rhyncosauroides footprints of Owen and others by Geoff Tresise of Liverpool Museum has shown them to be not related to the actual Rhyncosaur beast that has been found at Grinshill, but probably from a small archosaur reptile called a Protorosaur.
More photos of Sara's talk and the fossil footprints can be found on the Powysland Museum Facebook page.
The next meeting will be held on Wednesday 19th of February when Dr Geoff Steele will give a talk entitled “The Origins of Life”.