General—To join TVGS for the year, starting January 1st, the fee is £15. Members have free entry to evening talks, visitors £3 (if watching on Zoom a voluntary contribution would be appreciated). To make payments to TVGS–BACs: Sort 30-99-90 (Lloyds) , Account Number 69193560 • By Cheque to TVGS, c/o 2 Vernon Close Martley WR6 6QX • By Cash, either through the letterbox as above, or in person to John Nicklin or Dave Cropp. Whichever way you choose, it would help our records to know your contact details, so please email email@example.com once you have made payment, or include a note with your payment.
Note that Events are listed in REVERSE DATE ORDER
|Apr 2022||25||Dr. Nigel Woodcock, Cambridge University, “Sedgwick’s ‘Great Dislocation’ revisited: the Dent Fault, NW England” |
The Dent Fault is a 35 km long Variscan fault that throws the early Palaeozoic rocks of the Lake District against the Carboniferous rocks of the Yorkshire Dales. The talk describes the first description of the fault by Adam Sedgwick in the 1830s, and how it helped to improve interpretation of geological structure in general compared with the simpler views of William Smith. In the past twenty years the Dent Fault has again stimulated new views on how fault systems work and on the fault rocks that they produce. Finally, the structure across the Dent Fault and the Malverns is compared, through the involvement of John Phillips in early 19th century research in both areas.
|Mar 2022||28||Prof. Derek Siveter, University Museum of Natural History, Oxford, “ The Herefordshire Lagerstätte: a remarkable window into Silurian marine life” |
The Herefordshire Lagerstätte is an exceptional, globally important fossil deposit of mid-Silurian age (about 430 Ma), occurring in the Anglo-Welsh Basin. The fossils are hosted in nodules in a volcaniclastic layer and are represented by a rich soft-bodied invertebrate fauna. These are exquisitely preserved in the round and are studied mostly through use of physical-optical tomography. Digital images are combined by computer to reconstruct the animal as a three-dimensional virtual model that can be examined interactively on screen. The digital data can also be used to generate a physical model of the fossil through rapid prototyping technologies. Soft-bodied fossils belonging to the Cambrian Period have been fundamental for our understanding of the early evolution of animal life during the ‘Cambrian Explosion’ event. However, soft-bodied faunas from the Silurian are extremely rare, and the Herefordshire fossils are contributing much to our understanding of the palaeobiology of the wide variety of major invertebrate groups represented, and thus to the early Phanerozoic history of life on Earth.
|Feb 2022||28||Dr Carl Stevenson, Birmingham University, “Tectonics and magmatic structures in the West Midlands” |
The kinematics and history of major tectonic structures in the West Midlands and surrounding areas is linked with the ascent and emplacement of magma. Results from a series of student projects examining features including the Wren’s Nest, Lickey Hills, Malvern Lineament and the Rowley Regis Dolerite, Clee Hill Sill and other smaller intrusions are discussed and an emerging model presented for criticism. Can we link the kinematics of major tectonic structures to these intrusions? Does their timing/age of emplacement fit the tectonic history?
|Jan 2022||24||Prof Ian Fairchild, Birmingham University, “Stromatolites: Making Mountains out of Microbes” |
For most of Earth history the only macroscopic evidence of life comes from the intricately layered rocks called stromatolites. Like trace fossils they record an interaction between organisms and sedimentary processes. The key players are the cyanobacteria, formerly known as blue-green algae, which played a vital role in oxygenating the Earth through their photosynthesis. Build-up of sediments and precipitates over time under the sticky surface mats created by communities of such organisms can make limestone and dolomite masses up to hundreds of metres thick. Stromatolites reveal many fascinating stories of past environments and examples from several continents will be discussed.
|Nov 2021||29||Dr Seb Watt, Birmingham University, “Volcanic Tsunamis: Krakatau, 1883 and 2018” |
Although most tsunamis are generated by earthquakes, those generated by volcanic processes can cause devastating impacts. Volcanic-tsunami generation remains a poorly understood process but the hazard is significant, as demonstrated by the catastrophic eruption of Krakatau in 1883, where most of the 36,000 deaths were caused by the associated tsunami. A variety of volcanic processes can generate tsunamis, with unpredictable timing and the potential for locally extreme wave heights. Here, I will summarise results from ongoing research at Krakatau and other volcanic islands, drawing on insights from the 1883 eruption as well as the volcanic-landslide generated tsunami at Anak Krakatau in December 2018.
|Oct 2021||25||Prof. Rob Strachan, Portsmouth University, “A geotraverse across Shetland: new insights into the Scottish Caledonides“. |
Shetland is a microcosm of the Scottish Caledonides, containing potential correlatives of the Moine Thrust Zone, the Moine and Dalradian supergroups, and an overlying ophiolite derived from the Iapetus Ocean. New geochronology results shed exciting new insights into the geological evolution of this hitherto relatively poorly known part of Scotland.