220-5 The ChaSE project: Chalk Sea Ecosystems and Cretaceous environmental change in the Chalk Group of the United Kingdom

Session: Life and Environments Through Time and Space: Multi-Record Approaches to Stratigraphic Paleobiology (Posters)

Poster Booth No.: 131

Presenting Author:

Richard Twitchett

Authors:

Witts, James¹, Tangunan, Deborah², Bernard, Emma³, Bohun, Harriet⁴, Collins, Katie⁵, D'Souza, Leila⁶, Day, Mike⁷, Ewin, Timothy A.M.⁸, Fogherty, Thomas⁹, Griffiths, Chloe¹⁰, Howard, Richie¹¹, Hughes, Zoë¹², Jones, Marc¹³, Miller, Giles¹⁴, Spence, Kaia¹⁵

(1) Natural History Museum, London, LONDON, United Kingdom, (2) Earth Sciences, University College London, London, United Kingdom, (3) Natural History Museum, London, United Kingdom, (4) Imerial College, London, United Kingdom; Natural History Museum, London, United Kingdom, (5) Natural History Museum, London, United Kingdom, (6) Natural History Museum, London, United Kingdom, (7) Natural History Museum, London, United Kingdom, (8) Natural History Museum, London, United Kingdom, (9) Natural History Museum, London, United Kingdom, (10) Natural History Museum, London, United Kingdom, (11) Natural History Museum, London, United Kingdom, (12) Natural History Museum, London, United Kingdom, (13) Natural History Museum, London, United Kingdom, (14) Natural History Museum, London, United Kingdom, (15) University College, London, United Kingdom; Natural History Museum, London, United Kingdom, (16) Natural History Museum, London, United Kingdom, (17) University College London, London, United Kingdom; Natural History Museum, London, United Kingdom, (18) Natural History Museum, London, United Kingdom, (19) Earth Sciences, University College London, London, United Kingdom, (20) University of Portsmouth, Brading Sandown, United Kingdom; Natural History Museum, London, United Kingdom, (21) Network Stratigraphic, Potters Bar, Hertfordshire, United Kingdom, (22) School of Natural Sciences, Birkbeck College, University of London, London, United Kingdom, (23) Earth Sciences, University College London, London, , United Kingdom, (24) Natural History Museum, London, United Kingdom,

Abstract:

This poster showcases the work of the ChaSE (Chalk Sea Ecosystems) project. The onshore Chalk Group of the United Kingdom provides a continuous and well-exposed rock and fossil record spanning the Late Cretaceous (Cenomanian – Maastrichtian stages, ~100 - 72 Ma). As an economically important resource, the chalk has been quarried and studied for >200 years and a detailed stratigraphic framework is available. The sequence is abundantly fossiliferous, recording every marine trophic level from nanno- and phytoplankton to apex predators such as marine reptiles and sharks. Key events recorded in the Chalk include peak Cretaceous warming and biodiversity crisis across the Cenomanian – Turonian boundary (Oceanic Anoxic Event 2), the highest global sea-levels of the last 250 myrs during the Turonian, and a long-term cooling from the Coniacian onwards which culminates during the Maastrichtian with the coldest temperatures of the Late Cretaceous.

The Natural History Museum, London (NHMUK) alone contains >50,000 UK Chalk Group macrofossil specimens, including rare taxa and material from now inaccessible localities. Only a fraction of these have been published or are available in public datasets. Many specimens contain limited metadata, and ages or stratigraphic position are poorly constrained. To unlock these ‘dark data‘ we are re-dating >1,500 macrofossil specimens using calcareous nannofossil biostratigraphy. Combining these with specimens bearing excellent locality and stratigraphic information, as well as data from new fieldwork to localities across the UK, we are conducting the first ‘whole-ecosystem‘ study of the functional diversity and ecology of the Chalk Sea. These data will provide an unprecedented record of the effects of global Cretaceous climate change on marine ecosystems at a variety of temporal and spatial scales, all within the same depositional system.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8796

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