174 Environmental Instability During Greenhouse Periods: Impact on Terrestrial and Marine Ecosystems

Greenhouse conditions and transitions to and from such climate states put environmental stress on terrestrial and marine ecosystems. We invite contributions that leverage multidisciplinary/proxy approaches to constrain the impact of environmental changes on paleobiodiversity.

Tuesday, 21 October 2025
8:00 AM - 12:00 PM
HBGCC, 303C

Palaeoecological response to Earth System changes across the Cenomanian – Turonian boundary in the UK Chalk Sea

Paper number: 174-7
Program: Technical Sessions
Time: 9:40 AM – 9:55 AM

Authors

Abstract

The Cenomanian-Turonian boundary interval (Late Cretaceous ~93.9 myrs ago) coincides with a dramatic period of environmental change. This includes the global carbon cycle perturbation of Oceanic Anoxic Event 2 (OAE-2), rapid changes in seawater oxygenation and temperature on both a local and global scale (e.g., the ‘Plenus Cold Event’ and early Turonian thermal maximum), as well as sea level and productivity fluctuations. Despite a wealth of proxy and geological data, the effects of these events on the diversity and functional ecology of marine ecosystems remain uncertain. The Chalk Group of the United Kingdom provides a complete and abundantly fossiliferous record across this interval within the Anglo-Paris Basin, and is currently the focus of the ChaSE (Chalk Sea Ecosystems) project. Using extensive macrofossil collections from the expanded Cenomanian-Turonian marine sedimentary sequence exposed at Eastbourne (East Sussex, United Kingdom) held at the Natural History Museum, London as well as new quantitative field and geochemical proxy data, we document several intervals across the broad C-T boundary interval where the marine macrofauna in the UK Chalk Sea underwent significant changes in both taxonomic and functional diversity. We demonstrate how these data are related to and driven by each of the environmental changes outlined above, and how they provide important evidence for the complex regional response, and resilience, of marine ecosystems to Earth System perturbations in the greenhouse world of the Late Cretaceous.

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

doi: 10.1130/abs/2025AM-413349

© Copyright 2025 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.