Monthly talk: Monday 14th October 2024 

The history of building stone use in south Cambridgeshire churches

by Dr Nigel Woodcock Department of Earth Sciences, University of Cambridge

A geological survey of about 120 medieval churches in south Cambridgeshire reveals a dominant theme of local fieldstone rubble walls with dressings of local Cretaceous Clunch and imported Jurassic Barnack limestone; the richer the church the greater the volume of costly Barnack. The Cretaceous Ely Sandstone forms rubble walls only near the city. Victorian renovations to the medieval fabric of south Cambs churches used a much wider range of stone from the Lincolnshire Limestone Formation and further afield, made possible by new canal, then rail, networks. St Laurence at Foxton, for example, has fieldstone rubble walls, partly rendered, with medieval dressings of Barnack and Clunch, much repaired with Bath stone in the nineteenth century.

Monthly talk: Monday 11th November 2024  7.15 pm start

The oldest fossilised trees ever found

by Dr William McMahon, Dept of Earth Sciences, University of Cambridge

The finding of what’s thought to be Britain’s oldest fossilised trees, calamophyton, and the world’s earliest known fossilised forest, in the cliffs in the Devonian age Hangman Sandstone Formation in Somerset.

Please arrive at 7 pm for 7.15 start as the talk will be preceded by our (short) AGM

Monthly talk: Monday 9th December 2024 

The Geodiversity Landscapes of Cambridgeshire

by Dr Steve Boreham, CGS Geosites team & WildReach

The CGS Geosites team has recently developed a landscape approach to describing the geology of Cambridgeshire and the geological (and geomorphological) features to be found here. This sets the geology in a context familiar to most people and also links it with local ecology and the key role that it has played in the economic development of the county, from limestone, chalk and clay to gravel, sand and peat. Our aim is to provide a comprehensive description of local earth heritage and to promote its geoconservation.

Steve Boreham (BSc PhD) is a geologist and ecologist with a special interest in Southern England, East Anglia, Fenland and the Cambridge District. He worked for the University of Cambridge, managing laboratories and teaching field and laboratory classes for more than 30 years before retiring in 2020. Steve has published several papers on the geology of Cambridgeshire and works with the Cambridgeshire Geological Society to protect the county’s geodiversity. He also assists the National Trust at Wicken Fen, The Wildlife Trust BCN at Great Fen, and Hobson’s Conduit Trust in Cambridge to enhance biodiversity, improve water quality and to protect peatland resources.

Monthly talk: Monday 13th January 2025 

Members’ talks and New Year Social

A series of short talks by members and a chance to learn more about the Society and meet other members. Remember to bring a few rocks and fossils for the ;show and tell’ table. Refreshments available.

Monthly talk: Monday 10th February 2025 

Railway Quaternary Geology

by Dr Sebastian Gibson, Dept of Geography, University of Cambridge

The challenges for railway design of digging through Quaternary deposits with examples taken from HS2.

Monthly talk: Monday 10th March 2025 

Crossrail Construction

by Dr Ursula Lawrence, WSP (Real Estate and Infrastructure) Ltd

A summary of the Crossrail project, explaining the main construction methods for the tunnels and stations. The Cretaceous to Holocene geology encountered along the route is presented including both the impact the geology has on the engineering and how recent infrastructure investigations have developed our knowledge of the geology of London. It also compares and contrasts the London geology with the Gault, more familiar locally.

Ursula is an engineering geologist with 35 years experience of geotechnical design of major infrastructure projects having worked on Crossrail and various sections of HS2. Ursula has a PhD in Civil Engineering and a Chartered geologist. Ursula has been involved with both the Engineering and South East Regional Groups of the Geological Society culminating in Chair of the Engineering Group 2020-2022. She has published a number of papers on ground risk in major infrastructure, London Basin geology and groundwater and the Clay-with-flints Formation. She is currently Assistant Editor of Quarterly Journal of Engineering Geology and Hydrology.

Monthly talk: Monday 14th April 2025 

Shooting Stars and Space Rocks

by Paul Fellows, Cambridge Astronomical Association

Comets and Meteors can be an impressive sight in the night sky, but the study of them has told us a huge amount about the origins of the Solar System and the Planets including Earth. Paul will show where these space rocks and dirty snowballs come from, and the story that they reveal including the implications for life on Earth and beyond.

Having built his first telescope aged 14 and experiencing the “wow” of seeing the rings of Saturn for the first time, Paul has been stargazing for some 45 years and has his own private observatory where he images the sky. He is chairman of the Cambridge Astronomical Association and presents the public live observing evenings at the University of Cambridge to audiences of 200+ each week. He holds a Master’s degree in Natural Sciences from the University of Cambridge and a post-graduate degree in Computer Science, also from Cambridge. He is a Fellow of the Royal Astronomical Society and of the Institute of Engineering and Technology. Twice a winner of the Queen’s award for Technology he was recently presented a lifetime innovation award by Emmanuel College Cambridge.

Monthly talk: Monday 12th May 2025 

Unravelling the glacial history of Eastern England

by Prof Phil Gibbard, Dept of Geography, University of Cambridge

Monthly talk: Monday 9th June 2025 

Landscapes and environments of long ago

by Mike Tuke

How geologists determine ancient environments, illustrated by an accompanying collection of rocks which provide evidence of some of he typical features of those environments. An excellent introduction to geology and how the characteristics of various rocks reveal the earth’s history and how landscapes are formed.

Field trip: Friday 20th September 2024 

Day trip to Bradgate Park in Charnwood Forest, Leics

to see spectacular Late Pre-Cambrian Rocks and associated fossils

Guide: Dr Alex Liu, Dept of Earth Sciences, University of Cambridge, Leader: Lee Wells, CGS (and Penny Goggill, CGS)

We will be following a well-explained tour examining the fascinating rocks of this one-time volcanic region of the East Midlands. The rocks we will see will include, Precambrian, Cambrian, Triassic and Pleistocene Boulder Clay. Lunch: either own packed lunch or cafe/restaurant at Newton Linford. Distance of round walking trip: c.5km. Terrain: disused quarries and crags as well as tarmaced paths. No Hammers. Limited to 15 people. Needs to be booked and paid for in advance. Cost £5 per person. Car sharing possible -with shared petrol & (£4.50 per car) parking costs.

Monthly talk: Monday 9th September 2024 

Stratigraphy and Sedimentology of Northern European Chalks

by Dr Haydon Bailey, Past President of the Geologists’ Association & Geological Adviser for the Chiltern Society

Dr Haydon Bailey is an expert on the Chalk: ‘The Upper Cretaceous Chalks of Northern Europe appear, on the face of it, to represent sedimentation during an extended period of relative tectonic and environmental stability. Nothing could be further from the truth. These uniform, white, fine grained carbonates are the sediments result from constant change in water temperature, oxygen content, dynamic water currents both at the sea surface and at depth.

Back in 1994 I presented a talk at a European conference entitled “Chalk, white, as above!”, because that was the comment frequently seen on core logs, geologists’ description sheets and engineering geologists’ well logs. Just how much information were we losing because of this phrase? Over the last 30 years our understanding of chalk deposition, and the environmental conditions which control it, have fundamentally shifted. Hopefully I can convince you that this might be the case.’

Visit: Sunday 14th July 2024 2.30pm to 4.30pm

Living Fossils of the Botanic Garden, Cambridge

Guided by Franziska Norman, Cambridgeshire Geological Society

Franziska will show us the ‘living fossil’ plants she described in her talk last April that are flourishing in the Cambridge University Botanic Garden. She will take us on a tour of the glasshouses and the garden to see the plants that have been growing somewhere in the world since the middle of the Jurassic Period.

Easy walking, all welcome. Free but you do need to pay entry to the Botanic Garden (£8, free for Friends of the Garden). Please book (as it is limited to 15 people) by emailing us on info at cambsgeology.org to reserve a place. Details of the meeting place will be given after booking.

Monthly talk: Monday 10th June 2024 7.30pm

My favourite fossils held at the Sedgwick Museum

Rob Theodore, Exhibitions and Display Coordinator, Sedgwick Museum, Cambridge

Learn about some of the amazing fossils that are held by the world-famous Sedgwick Museum of Earth Sciences in Cambridge. This will be a personal look at some of Rob’s favourites.

This talk will be in our usual venue at St Andrew’s Centre, Histon.

Walk: Friday 14th June 2024 morning (10.30am to 12.30)

Building Stones of Cambridge

Celebrating Cambridge Nature Festival

Guided by Penny Coggill, Chair, Cambridgeshire Geological Society

By popular demand, a repeat of the walk held on Friday 7th June 2024 which was overbooked.

Cambridge is a beautiful city! Why? Because it has a great number of very fine buildings – university, ecclesiastical, public and commercial – built with some affluence, which meant the owners could use stone, and the more fashionable and pleasing to the eye that stone was the better. Join us for this guided walk around the city to see how these different stones were used, where they came from, how building and architectural fashions changed over time with improvements in transport and see what stones are used today to enhance the built environment. Our locally sourced stones tell us about the past environments of the area –  as seen in the fossils that many of them contain –  from Chalk ‘clunch’ to highly prized Jurassic limestones. Others, such as granites and ‘exotic’ pebbles tell the story of earth’s history elsewhere in the world. You will never walk through the city with the same eyes again.

Easy walking, about 1 mile total, all welcome, free (as it is part of the Cambridge Nature Festival) but you do need to book.Please email us on info at cambsgeology.org to reserve a place. Details of the meeting place will be given after booking.

Monthly talk: Monday 13th May 2024 7.30pm

Potential for carbon dioxide sequestration in volcanic rocks of the North Atlantic Igneous Province

by Dr Simon Passey, CASP

In the quest to achieve the objectives of the Paris Agreement, which aim to restrict anthropogenic warming to 1.5–2.0°C this century, carbon capture and storage (CCS) plays an indispensable role. The majority of CCS projects are focussed on the injection of carbon dioxide (CO₂) into porous sedimentary rocks at greater than 1 km depth; these require impermeable overlying rocks to stop the CO₂ escaping to the surface. An alternative approach, however, involves the injection of CO₂ into reactive rocks (e.g. mafic or ultramafic lithologies) leading to carbonate mineralisation; this process permanently locks carbon away with minimal risk of it re-entering the atmosphere. The CarbFix project in Iceland has made significant strides in demonstrating the viability of this approach by injecting CO₂ into basalt lava flows. The project is, however, on a relatively small scale and there are uncertainties regarding the feasibility of scaling up this technology for widespread commercial use, such as utilising the large volumes of volcanic rock formations of the North Atlantic Igneous Province (NAIP). These volcanic rock formations vary significantly in terms of facies, mineral composition, porosity and permeability, all factors that need to be addressed in adopting the CarbFix approach. The potential of carbon mineralisation within the NAIP will be explored and the challenges faced will be discussed.

Monthly talk: Monday 8th April 2024 7.30pm

Members evening – all welcome

A series of short talks and updates plus a chance to chat and find out more about geology and CGS. Light refreshments provided – please feel free to bring some contributions if you would like to. Non-members also very welcome. Includes:

Dr Terry Allsop – Old Svalbard

Chris Wagner. – Gault Clays in Cambridgeshire- An Engineer’s Perspective

     Lee Wells – Charnwood Forest

Monthly talk: Monday 11th March 2024 7.30pm

The interpretation of the periglacial landsystem through LiDAR

by Dr David Giles, Technical Director, Card Geotechnics Ltd

This presentation presents a review of the relict periglacial landsystem that gave rise to a significant ground legacy of geohazards and will demonstrate the advances in ground model assessment offered by airborne LiDAR (laser scanning) data sets for engineering geomorphology. High resolution digital elevation models derived from the LiDAR data can be utilised to interpret and visualise the on-ground geomorphology. Derivative models can be generated for hydrological studies providing a variety of new opportunities for ground model development. The available LiDAR data and generated models are described, and examples of their use presented from classic case study sites.

Monthly talk: Monday 8th Jan 2024 7.30pm

(not the 15th Jan as previously stated)

The Northwest Highlands Controversy

– How one man’s ego held back science

by Dr Reg Nicholls, previous Chair of CGS

The North West Highlands of Scotland can be classed as one of the most complex and interesting geological areas in the world. Due to its complexity, it was amongst the last to be properly mapped and explained. To this day new observations/evidence allows us to revise its story. The elucidation of the geology was not helped by the massive ego of one of the giants of 19^th century geology – Sir Roderick Impey Murchison! The story of the path to the geological truth has now been termed the “Northwest Highland Controversy”.

By the 1860’s Murchison was director of the Geological Survey and thus held great sway over the “accepted” opinion. Other academics who had studied the area were forming an alternative view of the geological story of the NW – but were “drowned-out” by the establishment. Murchison was on a mission to claim more and more territory for “his” Silurian system and was convinced that the mass of the rocks in Assynt were a conformable sequence of Silurian age – others (like Professor James Nicol of Aberdeen University) thought it was much more complicated. This had followed on from Murchison’s “brow-beating” of Adam Sedgwick into accepting the Silurian in Wales extended down to meet the Cambrian that Sedgwick had worked out.

By 1883, a new view was taken by Charles Lapworth (Prof University of Birmingham). He had already forced the Survey under Giekie (Murchison’s man) to have a volte face over the structure in the Southern Uplands and now he succeeded in establishing the true facts in the NW – much to Murchison’s displeasure. This talk will discuss the politics and personalities as well as the science that led to the fuller understanding of the rocks of the NW.

Monthly talk: Monday 11th Dec 2023 7.30pm

Introduction to the Geology of the Chalk Springs and Chalk Streams of Cambridgeshire

by Dr Steve Boreham

The Chalk Springs of Cambridgeshire provide a unique aquatic habitat and have a vital role in feeding the Chalk Streams that flow through the southern part of the county. These springs arise in a variety of styles and geological settings, and there is considerable debate about what constitutes a ‘chalk stream’. Spring types appear to be linked to the lithology and stratigraphy of the Cenomanian Chalk and their distribution may also be influenced by past glacial and periglacial activity. Understanding these variations is essential if the geodiversity of these landforms is to be preserved.

Field trip: Sunday 16th July 2023 10am

Great Fen Local Geological Site

 Led by Dr Steve Boreham, Chris Donnelly (CGS Geosites Team) & Henry Stanier (Wildlife Trust BCN)

Over recent years, the CGS Geosites team, with the help of Dr Steve Boreham, has been working with The Wildlife Trust BCN to highlight the geological importance of this key fenland site, also obtaining its designation as a Local Geological Site. This guided visit will explore the area to provide an understanding of the geology of the local and wider Fens and how it relates to both ecology and local history. We will see Holme Fen, which contains the remains of raised bogs and some of the deepest peat still surviving in fenland, and also the site of Whittlesea Mere, which has extensive deposits of shell (lake) marl. Underlain by Jurassic clay and ‘Ice Age’ gravels, the area also contains the ‘Fen clay’ from the Bronze Age marine incursion, seen within complex layers of buried peat or in small roddons at the surface, and the site of the ancient Trundle Mere, near to where the old River Nene enters the fenland. We will examine a core taken through the layers of peat that reveal the local history from the Neolithic and Bronze Age to the present. Visiting five sites, this will give a ‘behind the scenes’ insight into the Great Fen habitat restoration work and include a walk in Woodwalton Fen National Nature Reserve to enjoy the wildlife and see the historic Rothschild Bungalow. The area is rich in history and we will see the Holme Posts that show the dramatic effect of fenland drainage (particularly that of the famous mere), limestone blocks once destined for the walls of historic buildings as well as the remains of the old brick kiln at Ramsey Heights.

Easy walking during a few short walks. We can use the ‘facilities’ at Ramsey Heights Countryside Classroom, where we meet at 10 and return for a late lunch (coffee/tea/soft drinks provided but you will need to bring a picnic lunch). You will need to drive (in own vehicles) from Ramsey Heights Nature Reserve to the other sites – lift sharing may be possible.(Unfortunately, there is very limited public transport to within walking distance of Ramsey Heights NR and none to other sites visited). Info: www.wildlifebcn.org/nature-reserves/ramsey-heights. Full itinerary, maps and times provided after provisional booking. £5 CGS members (non members £6, subject to space availability). Contact us to book.

Fen Edge Trail Walk: Sunday 2nd July 2023 10am

Thorney – ‘an iconic fen island – monks, marshes and a model village’

 Led by Dot Halfhide (Thorney Museum) & Penny Coggill (CGS Chair & Fen Edge Trail Team)

In partnership with Thorney Museum and the Thorney Society. Well-known for its ancient Abbey, Thorney is also a good example of fenland’s interesting geological history. This will be a guided Landscape Heritage walk on the Fen Edge Trail on the ‘island’ of Thorney. The walk will cover cultural history, fenland landscape and  geology. Thorney, the ‘Isle of Thorns’, was a fen island surrounded by marshes until the drainage projects of the 17th century. It has been known since the 7th century for its major Benedictine Abbey; the large Abbey church remains impressive, even though much of it was lost in the 16th century. The Victorian village is of the characteristic local brick and is famous for being a ‘model village’, built in the 19th century under the Duke of Bedford’s ownership.

All welcome. £3 per person (payable in advance). Children free. Needs booking. About 2.5 hours to 12.30pm. Easy walking about 2 miles, slow walk, some on pavement, most on grassy tracks. For more details see the website www.fenedgetrail.org where you can also download the full Walk Guide. Contact us to book.

Visit to Cambridge Botanic Garden to see ‘Living Fossils’: Tuesday 27th June 2023 10.30am – 12 noon

 Led by Franziska Norman, CGS

Following Franziska’s fascinating talk on ‘Living Fossils’ to CGS in March, she has arranged a visit to the Botanic Garden where she will give a tour of the Garden to take in these ancient plants and see how they are growing and surviving in the UK.

The cost is just the usual entrance fee to the Garden of £7.20 or £8 including Gift Aid (free for Friends of the Garden). However, that will allow you to explore the garden after the tour is over and take refreshment in the café.

All welcome. Needs booking (more details given after booking). Easy walking. Contact us to book.

Fen Edge Trail Walk: Saturday 17th June 2023 10.30am

For Celebrate the Fens Day

 ‘through the fen edge town that became one of the world’s most famous cities’

 Led by Martin Evans, CGS Fen Edge Trail Team

Approx. 2.5 hours to 1 pm. For Celebrate the Fens Day, this walk starts on the distinctive landscape feature of Castle Hill (a Chalk hill) and finishes at the Sedgwick Museum of Earth Sciences. It gives a landscape heritage and geological perspective to the city: the river’s gravel terraces, the chalk stream-fed river and the ‘fen’ meadows of alluvium and peat. The walk will also draw attention to buildings and places of historical and social interest. Guiding you through what is now a mostly hidden landscape, the walk takes you back in time, giving a glimpse into the city’s past and the natural history of the area, from ‘Ice Ages’ to sub-tropical swamps and fenland rivers. You will discover how its natural character still filters through, seen in the riverside meadows, the numerous water channels, the subtle changes in the height of the land and even in the building stones used in many of its famous buildings.

All welcome. Free as part of Celebrate the Fens Day but needs booking in advance. Easy walking, about 3 miles. For more details see the website www.fenedgetrail.org where you can also download the full Walk Guide. Contact us to book.

Fen Edge Trail Walk: Sunday 21st May 2023 2.30pm

(postponed from 14th May)

The Old & New Bedford Rivers, Earith

‘along the great drains created in the 17th century by the Company of Adventurers’

Led by Peter Daldorph (The Word Garden) and Chris Donnelly (CGS Geosites & Fen Edge team)

This walk, at the southern end of the Ouse Washes near Earith, visits the two great ‘drains’ that created the Washes which now play a vital role in the flood management of the Fens whilst also being an internationally important wildlife conservation area. You will learn about the incredible construction of the the 100 Foot River (also called the New Bedford) by the Company of Adventurers in the 17th century during the ‘Common Wealth’ and the rule of Oliver Cromwell. This is also a good area to visit to understand the changes in the course of the River Great Ouse as it enters the fenland, and its links with the Old West River and the West Water.

All welcome, needs booking. £3 per person (to be paid in advance), children (under 18) free. Easy walking, about 2 miles, 1.5 hours to 4pm, but a longer walk is possible for those who wish. For more details see the website www.fenedgetrail.org where you can also download the full Walk Guide and accompanying podcast. Contact us to book.