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chalksea.bsky.social
ChaSE Project
@chalksea.bsky.social
240 followers 190 following 59 posts
Chalk Sea Ecosystems project, investigating marine ecosystem response to Cretaceous climate change. Funded by NERC, based at Natural History Museum, London and UCL. Account curated by Dr James Witts, NHM (@jdwitts.bsky.social). 🔗 chalksea.co.uk
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Reposted by ChaSE Project
marcehjones.bsky.social
Emma Bernard presenting her research as part of @chalksea.bsky.social that samples chalk nannofossils fossils from over 1000 Cretaceous fossil fish specimens at @nhm-london.bsky.social to significantly clarify their stratigraphic context.

Meeting Room Hall 4
#2025SVP
#SVP2025
Emma on stage in Meeting Room Hall 4 with her title slide.
November 14, 2025 at 9:41 AM
chalksea.bsky.social
#FossilFriday at #SVP2025 today! Emma Bernard will be talking about dating the amazing @nhm-london.bsky.social chalk fish collections at 09:30 in Hall 4. Then check out posters by Twitchett/Underwood and Kaia Spence on new #chalk sharks & coelacanth size in Poster Session III, Hall 3 (4:30 - 6:30).
A fossil coelacanth (Macropoma) from the Chalk in a drawer in the NHM London collections. Well preserved fossil fish from the Chalk in the NHM London collections.
November 14, 2025 at 8:35 AM
chalksea.bsky.social
A great time was had at the 'Festival of Geology' today! Thanks @geolassoc.bsky.social and @geolsoc.bsky.social for having us, and to all the enthusiastic visitors who were interested in our work. Thanks especially to @spissatella.bsky.social and Tessa for sharing your knowledge and helping out.
A flag outside the Geological Society of London advertising the Geologists Association Festival of Geology. Three people stand behind a table which is covered in chalk fossil, images of chalk fossils, and postcards/business cards. One person holds a chalk fossil echinoderm while another touches various chalk fossils on a table which is also covered with images of chalk fossils
November 1, 2025 at 6:55 PM
chalksea.bsky.social
If you're in #London today then come along to the @geolassoc.bsky.social FREE 'Festival of Geology' @geolsoc.bsky.social on Piccadilly. We'll be there showcasing some #chalk fossils and talking about our work on #Cretaceous ecosystems and environmental change. Come and say hello!
The library of the Geological Society of London with tables set out for the Festival of Geology. A series of chalk fossils and information about life in the chalk seas.
November 1, 2025 at 9:31 AM
chalksea.bsky.social
Great to be in San Antonio, Texas this week! 🇺🇸 We were at the @geosociety.bsky.social annual meeting, where @jdwitts.bsky.social & project PI Rich Twitchett presented a talk and poster on the latest science from ChaSE, studying #Cretaceous environmental and marine ecosystem change.
A billboard on the side of a large building advertising the Geological Society of America Connects 2025 conference. A man stands at a podium delivering a scke tirich talk. On the screen are images of chalk cliffs and a map. A large poster on a black board.
October 23, 2025 at 6:42 PM
Reposted by ChaSE Project
nhmbryozoa.bsky.social
#FossilFriday This large slab in the NHMUK covered with screws of the Carboniferous bryozoan Archimedes was unknown to me until last week. For at least 46 years it has been lurking among large specimens in the coral collection.
October 17, 2025 at 6:51 AM
chalksea.bsky.social
Historic specimens of the unusual #Cretaceous crinoids Marsupites and Uintacrinus @nhm-london.bsky.social made by Dr Arthur Rowe in the 1900s, including some beautiful pencil drawings. These extinct 'sea lilies' are abundant at certain levels in the #chalk making them useful for global correlation.
A museum drawer full of ball-shaped crinoid fossils. A fossil crinoid belonging to the genus Marsupites A pencil drawing of the test (skeleton) of the crinoid Uintacrinus. A pencil drawing of a crinoid skeleton.
October 15, 2025 at 8:15 AM
chalksea.bsky.social
#FossilFriday from the chalk seas of #Yorkshire - a good day in the field yesterday sampling a working chalk pit containing outcrops of the 'Black Band'; corresponding to #Cretaceous Ocean Anoxic Event 2. Thanks to the folks at Ashcourt Group for facilitating our visit!
An outcrop of chalk with a tape measure for scale. A prominent layer of dark shale - the 'Black Band' - runs through the middle of the sequence. A large chalk pit under a blue sky. A man in a high vis jacket and hard hat is examining the rock outcrops. A close up of a finely laminated rock showing small fossil burrows- proof thst even during an 'Ocean Anoxic Event' there was life on the sea floor. A red poppy growing on rubbly chalk.
October 10, 2025 at 9:40 AM
chalksea.bsky.social
🚨New ChaSE paper!🚨 'Slimehead Size Through Time'. Led by Masters student Chloe Griffiths, we used #chalk collections @nhm-london.bsky.social of the 🐟 genus Hoplopteryx & stable isotope analyses @ucl.ac.uk to see how fish body size varied with #Cretaceous climate change. 🌡📏 doi.org/10.1002/ece3...
Slimehead Size Through Time: Testing the Temperature–Size Relationship in Late Cretaceous Trachichthyidae
In this study, we use the extensive fossil record of the extinct Late Cretaceous Trachichthyid fish genus, Hoplopteryx, from the British Chalk Group to explore how this family responded to past clima...
doi.org
September 25, 2025 at 9:29 AM
chalksea.bsky.social
A good day in the field logging and sampling at high resolution new site containing a record of #Cretaceous 'Ocean Anoxic Event 2' (can you spot it?) near Ringstead, #Dorset yesterday. Plenty of finds for #FossilFriday including sharks, sea urchins, sponges, belemnites and fish!
A large quarry with a face made of chalk, a dark grey band runs across the center of the face. The sky is blue. A fossil echinoid with a scale bar and arrow pointing to the fossil. A fossil belemnite embedded in rock with a scale bar. A fossil gastropod (snail) with a tape measure for scale.
September 12, 2025 at 1:05 PM
chalksea.bsky.social
Great to be in Hannover at the 12th #Cretaceous Symposium! @jdwitts.bsky.social is presenting an overview of our #Chalk project @nhm-london.bsky.social @ucl.ac.uk
A poster on the work of the Chalk Sea Ecosystems project.
September 1, 2025 at 1:38 PM
Reposted by ChaSE Project
fossilsinthills.bsky.social
Picture in your mind a shark tooth... We bet this isnt the shape you were thinking of!

The shark Ptychodus had a 'pavement' of these strange teeth for crushing hard-shelled prey. Ptychodus fossils have been found all over the world, including from Hessle near Hull.

🏛️ Sedgwick Museum #FossilFriday
August 15, 2025 at 9:30 AM
Reposted by ChaSE Project
jdwitts.bsky.social
Some of today's #chalk views at Eastbourne. 🚁 🐚
August 6, 2025 at 6:00 PM
chalksea.bsky.social
#FossilFriday. In 1950, 10-year-old Stephen found a fossil #sponge on the beach at Seaford, East Sussex & donated it @nhm-london.bsky.social. 75 years later, Stephen visited us to see the specimen! Thanks to all the #ChalkHeroes who donated their finds over the years and make our research possible.
A man holding up an ornately written certificate A flint nodule containing a fossil sponge in a white box. Two labels identify it as Plinthosella from the upper chalk, Seaford Sussex
August 1, 2025 at 9:55 AM
chalksea.bsky.social
Yesterday was #MicrobalanceMonday. Working at the Bloomsbury Environmental Isotope Facility @ucl.ac.uk weighing out #chalk samples for carbon & oxygen isotope analyses. These will tell us about both temperature and carbon cycling in the chalk sea. UCL campus also has some lovely spots for a break!
A laboratory work bench with a microbalance, some glassware, and tubes filled with white powder A view looking up through some trees to a blue sky
July 29, 2025 at 7:25 AM
chalksea.bsky.social
#MolluscMonday a selection of inoceramid bivalves (and bonus sponges!) from the late Cenomanian Plenus Marls at #Eastbourne. These rocks were deposited during a period of #Cretaceous climate change known as 'Oceanic Anoxic Event 2', but these unusual clams don't seem to mind.
A large fossil clam embedded in a grey rock with a black-and-white scale bar. A large clam fossil embedded in a grey rock with a black-and-white scale bar. A large clam (labelled 37) and a sponge (38) fossil embedded in grey rock with a tape measure for scale. Fossils of a large clam (56) and sponge (57) embedded in a grey rock with a yellow tape measure for scale.
July 21, 2025 at 9:15 AM
chalksea.bsky.social
Highlighting a new paper from our team for #FossilFriday! On the discovery and diversity of bone-eating worms in historically collected marine reptile specimens @nhm-london.bsky.social from the UK #chalk.
marcehjones.bsky.social Marc Jones @marcehjones.bsky.social · Jul 17
Happy Birthday #EuniceNewtonFoote! 🎂
She would be 206 years old today!

We recently named the trace fossil #Osspecuseunicefooteae after her in this study led by @plesiosarahs.bsky.social on Cretaceous bone-eating worms:
- journals.plos.org/plosone/arti...
- journals.plos.org/plosone/arti...

🦴🪱
Images of the trace fossil Osspecus eunicefooteae. The inset shows a post mortem burrow in the bone of an fossilised ichthyosaur (from the Cretaceous of the UK) as seen in a slice from a micro X-ray CT scan. The main panel shows a 3D digital model of the burrow made in specialist software (Avizo) by tracing the burrow slice by slice. The burrow is about 2.7 mm across.
July 18, 2025 at 3:51 PM
Reposted by ChaSE Project
jdwitts.bsky.social
Looking forward to a fun few days of science and catching up with coclleagues @lifeandplanet.bsky.social @geolsoc.bsky.social. Our @chalksea.bsky.social project has two posters and a talk on #Cretaceous environmental change and effects on marine ecosystems. Come and say hello!
A man stands at a podium in front of a dcreen advertising 'Life and Planet 2025' Two scientific posters set up in a library.
July 14, 2025 at 9:11 AM
chalksea.bsky.social
It's the final day of the #FossilFestival at Lyme Regis! Still time to join our team in The Hub to learn about our science reconstructing #Cretaceous ecosystems, handle some chalk fossils from @nhm-london.bsky.social, and draw your own #ChalkSea creatures.
A group of smiling people stand behind a table which is covered by fossils and pictures of chalk fossils. A large poster with a reconstruction of a water column on which people have drawn reconstructions of fossil animals on stickers.
June 15, 2025 at 8:37 AM
chalksea.bsky.social
We had a great first day at Lyme Regis #FossilFestival talking to a lot of visitors from local schools, somem fabulous additions to our #chalk ecosystem! If you fancy drawing your own #Cretaceous creature and learning more about our project, we're in The Hub today!
A group of people working for the Natural History Museum stand behind a table of fossils in a marquee. A poster representing an ancient seafloor environment covered in drawings of fossils
June 14, 2025 at 7:16 AM
chalksea.bsky.social
Fun few days #fieldwork touring and logging beautiful Cenomanian - Campanian chalk outcrops in North Lincolnshire and Yorkshire with Prof Andy Gale and Paul Hildreth. Including exposures of the 'Black Band', the northern expression of #Cretaceous Oceanic Anoxic Event 2.
An exposure of rock (chalk) mostly white and grey. A distinctive black and grey layer runs horizontally through the center of the photo. There is a geological hammer for scale at the base. A sea arch cut into white chalk cliffs with a field of boulders in the foreground. The chalk shows obvious bedding and dark grey flint layers. A man in a black coat and white hard hat looks at a cliff of white chalk showing obvious layering. A man in a high visibility jacket uses a geological hammer to expose layers of rock at the base of a low cliff.
April 18, 2025 at 7:45 AM
chalksea.bsky.social
Lovely day in the field at Culver Cliff (Isle of Wight) with @echinerd.bsky.social and PhD student Chia-Hsin Hsu. We looked at the beautifully bedded Cenomanian-Turonian #chalk, finding plenty of echinoderms, bivalves, serpulids and even a nice nautilid!
Three people stand talking in front of a cliff made up of distinct bands of light and dark coloured chalk. A fossil echinoderm in white chalk. A finger for scale! The impression of a large fossil Nautilus in grey chalk. A black and white scale bar is at the top of the photo. A tiny star-shaped ossicle from a fossil crinoid in the chalk. With a finger for scale.
April 9, 2025 at 5:54 PM
chalksea.bsky.social
#FossilFriday Chalk Sea fish, big and small! From the amazing historic chalk collections of Booth Museum of Natural History in #Brighton. Part of ongoing research to understand how these fish were affected by #Cretaceous climate change. 🐟🌡
Skeleton of a fossil coelacanth fish (Macropoma mantelli) preserved on a block of chalk. A cm scale bar is present at the top. A beautifully preserved fossil fish (Ctenothrissa radians) complete with scales, sitting on top of a block of chalk on a white background. A cm scale bar is at the bottom left. A person measuring a fossil fish skeleton using a pair of digital calipers. A tiny fossil fish skeleton preserved in a block of chalk. The scale bar above shows it is only 3cm in size.
April 4, 2025 at 10:54 AM
chalksea.bsky.social
#MacropomaMonday - MRes student Kaia Spence is at UCL this week, preparing samples of chalk matrix for stable isotope analysis. By comparing oxygen isotope/temperature data with morphometric measurements from fossils, Kaia is examining how body size in coelacanths was affected by climate change.
A well-preserved fossil fish skeleton sitting in chalk matrix within a wooden box. Someone using a razor blade to scrape chalk matrix off the side of a fossil skeleton onto a piece of paper. A fossil fish skeleton set in chalk. A small area of the matrix is visibly whiter where a sample has been taken for stable isotope analysis.
March 10, 2025 at 9:43 AM
chalksea.bsky.social
Welcome to new PhD student Chia-Hsin Hsu from @unisouthampton.bsky.social - Chia-Hsin will be studying morphological evolution of echinoids from the #Cretaceous chalk sea. Including these beautiful Hagenowia from #Yorkshire.
A man with dark hair and glasses examines fossils in chalk blocks from a wooden drawer. Several pieces of chalk containing unusually shaped fossil sea urchins. A label says they are from Yorkshire.
February 19, 2025 at 10:48 AM