Winter Programme Abstracts 2023-2024

2023


Wednesday 21
st September


Stromatolites: Making Mountains out of Microbes (WGCG)
Professor Ian Fairchild (University of Birmingham)


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Stromatolite palmistry? Course of future evolution foretold?

For most of Earth history the only macroscopic evidences of life are 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 by 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 are discussed.

The YouTube link for this talk is:  https://youtu.be/5FjXmQpw7xk

Wednesday 11th October

Excavating Plesiosaurs
Richard Forrest (Peterborough Geological and Palaeontological Group)

Marine reptiles of the Jurassic, found in the UK, represent the largest collection of these amazing and charismatic animals from anywhere in the world. Museum collections contain many hundreds of such specimens, and many more are in in private collections, both in the UK, and other countries. Most specimens in such collections are relatively poorly documented. This limits the possibilities for unravelling the stories of the life and death of these animals from such scant evidence.
New specimens turn up regularly, but mainly from sea cliffs, or quarries, where there is a narrow window of opportunity to collect. Many are lost to quarrying operations or erosion, or are collected piece-meal and distributed between several different collections.
The Peterborough Geological and Palaeontological Group has developed a close working relationship with managers and operators, and by doing so has gained access to working quarries. When significant finds are made, it has been possible to carry out systematic excavation of several large marine reptiles with the full cooperation of the quarry management. This careful approach to uncovering and collecting such specimens, has recorded a wealth of data which can be used for scientific studies of taxonomy, taphonomy, sedimentology and other fields of research.
This talk is about three such finds made by members of the group.

Thursday 16th November

The Geology and Birds of Flamborough Head (WGCG)
Paul Hildreth (YGS)

Flamborough Head is Englands' most northerly outcrop of the Late Cretaceous Chalk Group, and is home to the highest chalk sea cliffs, and the only mainland gannet colony in the UK. In recognition of these latter claims, the RSPB has established the very popular, and successful, Bempton Cliffs Reserve which sees around half a million seabirds gather here, between March and October, to raise a family on towering cliffs overlooking the North Sea. Perhaps the most popular attraction is the puffin colony, though each visitor will have his or her own favourite.
The headland, founded on solid chalk, has a blanket of Quaternary deposits, mainly till and stratified gravels. In places such as Danes Dyke, these deposits fill deep ravines cut into the chalk bedrock, and provide a completely different habitat from the cliffs at Bempton. A walk from the car park to the beach, in early May, will take you through woodland where the sometimes harsh calls of seabirds give way to the more melodious sounds of the blackcap, wren and robin and the ‘tapping’ of woodpeckers.
The ornithologist notes that the northern side of Flamborough Head hosts most, if not all, of the breeding sites for sea birds such as gannet, guillemot, razorbill and puffin. The geologist notes that the Chalk of the northern side of the headland is different from that on the southern side, and that there is a significant variation in the influence of the Quaternary “blanket”. So this talk combines these observations, and looks for possible geological explanations to variations in bird distribution. In doing so I throw in some questions based on observation: do guillemots use clinometers; can seabirds recognise deformed rock layers; and are gannets and auks fellow members of the Flint Appreciation Society?
The preparation of this talk was helped by the staff at RSPB Bempton Cliffs; in particular Sarah Aitken, with whom I collaborated for a number of years, and for whom the YGS produced an information leaflet ‘The Geology of Bempton Cliffs’ for visitors to the reserve. Peter and Sylvia Nettleship, of Buckton, provided historical data, and a ‘seabird fact sheet’; and almost all of the stunning bird portraits are supplied by an old-school friend, Tony Malt from Malton, who came on a Yorkshire Geology Month boat trip from North Landing in 2016.



Thursday 18th January 2024

Volcanoes in the spotlight;  Exciting examples from La Palma, Stromboli and the ancient rock record (WGCG)
Dougal Jerram

Recent advances in the capture of 3D geological data has re-invigorated the way in which we study volcanoes and their deposits. The recent eruption on La Palma, and ongoing active volcanoes such as Stromboli, act as modern-day laboratories, to observe and record, while the ancient rock record is the legacy of such eruptions. Here we explore some exciting footage, and details of the 2021 La Palma eruption, which Dougal visited in person. We hear about techniques developed for mapping volcanoes in 3D on Stromboli, and will look forward to the role of digital geology in the ancient rock record.
The YouTube link for this talk is: https://www.youtube.com/watch?v=xb__01XJ9sY


Wednesday 14th February

Metal capture by Tufa: a natural process to engineering solutions?
Dr Susan Cumberland (University of Leicester)

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The leaching of heavy metals from legacy post-industrial slag, and other anthropogenic waste sites, is detrimental for human health and the wider environment. Tufa is a surface mineralised material that forms naturally when calcium-rich groundwater is exchanged with atmospheric CO2 at mid- to hyper-alkaline pH, resulting in a precipitation of calcite (CaCO3). Anthropogenic tufa may occur at old industrial sites (e.g. mining, steel works, paper mills) across northern England and Scotland. At the Howden Burn, near Consett in NE England, tufa forms in the stream as it emerges from the slag from the old steel works. Analysis of the streamwater, downstream of the tufa, shows metal concentrations are lower compared to those upstream. Examination of the solid tufa shows the presence of lead, arsenic, vanadium and zinc up to several 100 ppm. Cross-sectional element maps, at high resolution, of the tufa, using synchrotron µ-X-ray fluorescence (μXRF), reveal interesting pattens of metal distribution within the tufa laminations. This leads to the hypothesis that the metals precipitate together with the tufa during formation. Understanding, and exploitation of, artificial tufa for metal capture could have potential as a CO2 positive solution for sustainable in-stream remediation. This potential led to conducting experiments in engineering tufa to clean up metal leaching, as part of a doctoral project, and some preliminary results are shown.

Thursday 15th February


The caves of North Greenland - physical records of cryptic geological intervals (WGCG)

Professor Paul Smith (Oxford University Museum of Natural History)

Carbonate rocks of Neoproterozoic to Silurian age are abundantly distributed around the coasts of North and North-East Greenland. Large cave entrances are distributed across the whole of North Greenland, an ice-free area larger than England, from 80–82.5°N, and they constitute the northernmost documented karst caves globally. Data relating to the caves in this remote region have been collected on field expeditions over a 40-year period, and they provide information about palaeoclimates in otherwise poorly-documented geological intervals. These geologically young caves are mainly phreatic (sub-water table) conduits, and they are consistently located a few 100 m beneath the distinctive plateau that characterises the topography of the northern coast. Their identical context suggests that they developed in a single phase of cave formation; and the timing of cave development is constrained by the mid- to late-Miocene (15–5Ma) uplift of the plateau surface, and the onset of fjord-forming glaciation, in the latest Pliocene – earliest Pleistocene (c. 2.7–2.5 Ma). The caves of North and North-East Greenland offer a glimpse of large-scale phreatic drainage-systems that developed below an uplifted coastal peneplain during Neogene time. They preserve an important part of the geological history of North and North-East Greenland, that is otherwise absent from the physical geological record.


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