An assessment of sediment noise modelling on the Upper Jurassic Kimmeridge Clay: Implications for aquifer-eustasy

• Published in: Proceedings of the Geologists' Association p. 101136
• Main Authors: Davies, Andrew, Simmons, Michael D.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2025
• Subjects: Aquifer-eustasy; DYNOT; Eustasy; Kimmeridge Clay Formation; Relative sea-level; Sediment noise modelling; Upper Jurassic; Aquifer-eustasy; Relative sea-level; Upper Jurassic; Sediment noise modelling; Kimmeridge Clay Formation; DYNOT; Eustasy
• ISSN: 0016-7878
• DOI: 10.1016/j.pgeola.2025.101136

Relative sea-level curves obtained from analysis of the stratigraphic record provide crucial insights into various aspects of the Earth system. In recent years, several studies have employed sediment noise modelling (DYNOT and lag-1 autocorrelation coefficient) of astronomically tuned records to obtain information on changes in water depth and relative sea-level. Many of these studies provide support for aquifer-eustasy by demonstrating an out of phase relationship between relative lake level (from sediment noise modelling) and published eustatic curves. However, few studies have validated the sea/lake level curves derived from sediment noise modelling with independent water depth indicators. Here sediment noise modelling is critically evaluated using data from the Upper Jurassic Kimmeridge Clay Formation of the southern UK, where astronomical forcing has previously been demonstrated. Sediment noise modelling-derived water depth records are compared to detrital quartz-silt concentrations, previously shown to be an excellent proxy for relative sea-level changes through correlation with contemporaneous proximal successions. There is minimal correlation between the sediment noise modelling results and the independent quartz-silt record. Consequently, more research is required to demonstrate the validity of sediment noise modelling as a proxy for water depth change in sedimentary successions. This work implies that support for aquifer-eustasy as a primary driver of short-term, moderate magnitude sea-level change from sediment noise modelling studies should be re-evaluated.