Winter Programme 2021-2022

This seasons talks, again, will be, for the foreseeable future, on-line via Zoom. There is a reciprocal arrangement between ourselves - LL&PS Section C - and the Warwickshire Geological Conservation Group - WGCG - to share presentations. Those arranged by WGCG are annotated.
Non-members are directed to our Membership page - the Yearly subscription (September - September) is very modest.

Wednesday 15th September 2021
Dr Jonathon Paul

Subsurface engineering and water resources of Greater London

Wednesday 29th September 2021

Cindy Howells (National Museum Wales)

Dinosaurs and Deserts in South Wales

Recent discoveries, of new footprints and fossilised dinosaur bones, have increased our understanding of the terrestrial environments and faunas that existed during the Late Triassic and early Jurassic in south Wales. Hot deserts were subject to seasonal flooding events that preserved many footprints of both dinosaurs and other reptiles, in harsh environments where bone material did not fossilise. Subsequent sea-level rise created an island archipelago, where a diverse fauna of small vertebrates, including dinosaurs, lived within a karst landscape which preserved their fossilised bones and teeth in fissure deposits. Theropod dinosaurs are poorly represented from the earliest Jurassic, so the discovery of a partial articulated skeleton will bring better insights into the evolutionary relationships of this group.

Wednesday 27th October 2021
Dr Katie Strang (Scottish Geology Trust)

Celebrating Scotland’s geological heritage with the Scottish Geology Trust

The Scottish Geology Trust was launched in 2020, with the key objective of inspiring people, everywhere, to understand, love and care for, Scotland’s incredible geological heritage; and its' role in creating a sustainable future. From the 1st of September to the 17th October, the Trust, and partners, will deliver a packed programme of activities as part of the Scottish Geology Festival, from Stranraer to Shetland, that will showcase and celebrate Scotland’s geology. Join the Trust’s Secretary, Dr Katie Strang, for a virtual tour around Scotland’s most loved geological sites, and the fantastic festival events that are taking place around the country; and to hear more about the work the Trust has been doing to inspire and engage people with the rocks beneath their feet, and how important these are for exploring our future.

Thursday 18th November 2021
Professor Lindy Elkins-Tanton (School of Earth and Space Exploration, Arizona State University)
61st Annual Bennett Lecture - School of Geography, Geology & the Environment, University of Leicester

The NASA Psyche mission: Journey to a Metallic World

When our solar system was just an infant, thousands of planetesimals formed in fewer than one million years. Heat from the decay of the short-lived radioactive 26Al melted many planetesimals; allowing metal cores to differentiate from rocky mantles. Over the next few tens of millions of years, many planetesimals crossed paths catastrophically. Colliding worlds merged into even larger planets, eventually forming a small number of planetary embryos. Models show that some destructive “hit and run” impacts strip the silicate mantle from differentiated bodies. This is the leading hypothesis for the formation of asteroid 16's, Psyche, formation: it is a bare planetesimal core.
In 15 months time, the NASA Psyche mission will be launched to begin humankinds’s first exploration of a metallic world. This talk will introduce what is known, and what is hypothesized, about Psyche; how a mission to an unknown object was planned; where we are in the building of the spacecraft; and what we will measure, and discover, while our robotic spacecraft is orbiting the asteroid.

Wednesday 24th November 2021
Dr Seb Watt (University of Birmingham)

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; when 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.

Wednesday 15th December 2021
Professor Stuart Burley Emeritus Chair in Geology, Basin Dynamics Research Group, Keele University - Director, Discovery Geoscience, Lapworth, Warwickshire (WGCG)

A very British summer in the late Triassic: torrential rain; the Arden Sandstone; and the dawn of the dinosaurs

The Arden Sandstone Formation is a late-Triassic, distinctive, buff- to pale green-coloured sandstone and mudstone unit of Carnian age. Stratigraphically, the Arden Sandstone can be used to divide the Mercia Mudstone Group into a lower unit, of dominantly red desert mudstones - the Sidmouth Formation; from an upper unit, of rather similar, red desert mudstones - the Branscombe Formation. It is the lateral equivalent of evaporite deposits (Figure 1).


Figure 1. Triassic stratigraphy in a N-S section from the Wessex Basin, through the West Midlands, into the East Midlands, showing the occurrence of the Arden Sandstone (based on Newell, 2017).

A truly, local Warwickshire formation, it is named from its type section on the Grand Union Canal at Shrewley, that was first described by the Rev. Peter Bellinger Brodie, of Rowington, in 1856; and is now an SSSI. Indeed, the British Geological Survey reference sections are at Rowington (also on the Grand Union Canal), and in a cutting on Blackford Hill, SE of Henley-in-Arden. In fact, a similar thin sandstone sequence occurs across the Wessex Basin of southern Britain, through the Worcester Basin northwards into the West Midlands, then eastwards onto the East Midlands Shelf. A typical Arden Sandstone succession is up to 10m in thickness, and comprises thinly bedded, sharp-based, very fine to fine grained, rippled sandstones, which are overlain by thicker sets of cross-bedded sandstones that have high-energy plane beds. This upper unit has been widely used as a local building stone in Warwickshire, including in the construction of the fine St Peter’s Church in Wootton Wawen (and many other churches); and the National Trust medieval manor house at Baddesley Clinton.
The Rev. Brodie, vicar of Rowington from 1853 to 1897, and president of the Geological Society of London for 1894, found fossil fish and footprints of the reptile Rhynchosaurides from Shrewley and Rowington; whilst his son, Douglas Brodie, faithfully following in his fathers’ footsteps, described Chirotherium footprints (the famous ‘hand beast’) from near Preston Bagot (specifically ‘Whitley Green’), which is likely very close to the Blackford Hill exposure. Some of these rare fossil finds are on display in Warwick Museum, whilst examination of the Arden Sandstone, around Warwickshire, reveals abundant crustacean and worm burrows; desiccation cracks; common clam shrimp fossils of the genus Euestheria; plant remains; and small abraded remains of reptile bones (Figure 2).


Figure 2. A. Drawings of Semionotus fossil fish discovered by Rev. Brodie in the Arden Sandstone at Shrewley. B. Rhynchosaurides tracks found by Brodie in the Arden Sandstone at Shrewley, now in Warwick Museum (from Radley, 2005). C. Horsetail fossil plant remains from the Arden Sandstone at Badgers Dell, Baddesley Clinton. D. Cluster of Euestheria clam shrimp shells from the Arden Sandstone at Blackford Hill road cutting, Henley-in-Arden. E. Thin section micrograph from the Arden Sandstone coarse bed, also at Henley-in-Arden. Blue colour is dyed epoxy used to make the thin section and represents pore space between grains. The large yellow coloured grain is a bone fragment, probably that of a reptile.

The red-coloured Mercia Mudstone Group mudstones represent the deposits of extensive, flat-lying, desert alluvial plains; similar to those of the modern Ranns of Kutch in western India. Dolomitic soils developed on these alluvial plains, and ephemeral lakes formed in the adjacent basin centres. Gypsum nodules were precipitated in the soils, and when the lakes dried out, evaporitic halite beds were deposited. Studies of Carnian deposits, worldwide, have identified this as a time of major global climatic and evolutionary change. The recognition of dramatically increased rainfall at this time, gave rise to the term ‘Carnian Pluvial Episode’ (Simms & Ruffell, 2018). In this context, the Arden Sandstone records progradation of the Mercia Mudstone Group inland lakes; and deposition of sandy, lake-margin deposits. These were locally fed by fast-flowing ephemeral rivers, as in ‘flash floods’, exemplified by the sequences exposed at Rowington and Inkberrow, which now record the deposits of small lake deltas, or terminal splays. Clam shrimps, known today, from ephemeral fresh-water ponds and lakes, fed on algal mats in the temporary ponds, and were in turn eaten by Triassic amphibians and reptiles, that wandered the lake shorelines. Fish thrived in the shallow lakes, and Crurotarsans, the precursors of crocodiles, ate the crustaceans and fish. At the beginning of the Carnian, 90% of tetrapods were Crurotarsans. Some 8 ma later, at the start of the Norian period, Dinosauria dominated the tetrapod population (Figure 3). The cause of this extreme variation in the Triassic climate is elusive, but many geologists consider the contemporary, extensive, volcanic eruptions in western North America, as the driver for late Triassic climate change. These volcanic eruptions resulted in huge amounts of CO
2 being released into the late Triassic atmosphere, leading to increased rainfall, dramatic global warming, and rapid ocean acidification; thus turning a dry world, dominated by large deserts in the central part of the Pangaea super-continent, into a much more humid and wetter environment. Palaeontologists believe that the rapid diversification in the Dinosauria and related tetrapods, including turtles, crocodiles and lizards, was triggered by a major worldwide floral change that was directly associated with the Carnian Pluvial Episode. During this episode older floras, dominated by the seed-ferns, were replaced by conifers. So, on a pleasant sunny day, you can gently wander along the banks of the Grand Union Canal, to visit these important outcrops, trace the Rev. Brodie’s footsteps, imagine the torrential flooding of the Carnian desert, blooms of clam shrimps in ephemeral pools, and envisage the dawn of the dinosaurs, in the green sediments of the Arden Sandstone....

Mid December
Seasonal Social Meeting (tbc)

Wednesday 12th January 2022
Dr Aaron Hunter

The secret life of the starfish/crinoid

Wednesday 19th January 2022
Dr Rob Vernon rtd. (Coal Board)

Mining on the Iberian Peninsula (WGCG)

Wednesday 9th February 2022

Dr Ben Clarke (University of Cambridge)

Ethiopian volcanics (tbc)

Wednesday 16th February 2022
Dr Simon Drake (Research Associate, Birkbeck University of London)

The Kilchrist Caldera on Skye (WGCG)

Wednesday 9th March 2022

Wednesday 16th March 2022
Emeritus Professor Alex Maltman (Aberystwyth University)

Wine Whisky & Beer - the rôle of geology (WGCG)

Monday 4th April 2022
Professor Jane Francis DCMG FRS (Director British Antarctic Survey).

From Greenhouse to Icehouse; from Forests to Frosts. Antartica's Climate History

Wednesday 20th April 2022
Dr Stephan Lautenschlager (University of Birmingham)

Jurassic Brain Teasers (WGCG)