Monthly Lecture – 21st of May 2026

Zechstein platforms in the Southern North Sea were thought to be fringed by kilometre-scale high-energy progradational carbonates with lowstand wedge geometries. Instead, the Pensacola exploration well (41/05-2) encountered a halite-rich evaporitic wedge that replicates the coveted progradational carbonates.

Wedge precipitation predated the well-characterised basin-wide Z2 drawdown event, and therefore the localised evaporitic progradational system was onlapped by basin-fill halite. The evaporitic wedges often feature domino slumping along weak progradational bedding planes, resulting in blocks that collapsed into the basin. The earliest progradational beds contained the highest concentration of microbialites, and microbial fragments were reworked downslope into brecciated debris flow deposits demonstrating the relationship between wedge construction and syndepositional collapse.

This analysis characterises a rare evaporitic phenomenon which can hide in plain sight in seismic data and act as a depositional intermediary between platform construction and basin-fill halite precipitation.

 

About the speaker

Thomas’ research at the University of Aberdeen focusses on the Zechstein deposits of the Mid North Sea High and surrounding area. Whilst the earlier work demonstrated the importance of regional reinterpretation of legacy exploration data, privileged access to modern seismic data and new wells allowed for the analysis of unique depositional geometries that are rarely observed in the stratigraphic record. Funded by the GeoNetZero Centre for Doctoral Training, Thomas’ research not only derisks frontier exploration but also provides groundwork for emerging low-carbon technologies that will depend on robust sedimentological and palaeoenvironmental descriptions of the Zechstein. Thomas is due to submit their PhD thesis this summer, which will contain two completed publications and two manuscripts current under review.

 

Program:
17:30-18:00 hrs: Social hour
18:00-19:00 hrs: Lecture
19:00-20:00 hrs: Social hour

Venue:
Oudaen, Oudegracht 99, Utrecht