Ongoing Research Projects

North Sea Dome influence on geochemical evolution of Lower Jurassic intervals

Update November 2023 (New!): Our manuscript was accepted within Global and Planetary Change, check this link.

Update May 2023: We submitted our manuscript to Global and Planetary Change and we are currently under a major revision.

Update November 2022: We submitted our manuscript to PPP in June 2022 and it was also rejected. Now, we have re-evaluated the structure of the paper and plan to submit soon another journal.

Update January 2022: Paper submitted to EPSL December 2021. Stay tuned for the paper!

Update May 2022: The paper in EPSL was rejected. Its subsequent revision submitted to PPP also just received a rejection. While an upsetting decision given the amount of work put into each phase, I still think this exciting work will find a home somewhere.

Abstract

The Early to Middle Jurassic (~201-163.5 Ma) was characterized by major fluctuations in Earth’s climate, global tectonic activity, and large-scale magmatic events. However, there is a scarcity of records within the Viking Corridor during this time interval that provide a broader context of punctuated events. Considerable focus has been applied to understand the mechanisms that triggered the Early Jurassic Toarcian Oceanic Anoxic Event (TOAE; ~183 Ma)—a warming episode associated with a perturbation of the carbon cycle marked by a negative carbon δ13C isotope excursion (CIE). The event is linked to the release of CO2 from the Karoo-Ferrar Large Igneous Province (KF-LIP), resulting in euxinic (anoxic and sulfidic) marine conditions. Despite extensive study of the TOAE, these records are: 1) from the NW European epicontinental shelf; 2) solely based on δ13Corg; 3) of low-resolution; and/or 4) span short time intervals. Moreover, less focus has been placed on assessing pre- and post-TOAE events, such as the uplift and eruption of the North Sea Dome (NSD; ~182-170 Ma) within the Viking Corridor. The NSD uplift is a local feature that is commonly invoked as a driver of regional paleoclimatic conditions that acted as a thermal barrier between warm Tethyan Ocean and cooler waters from the Boreal Sea. This study contributes new, high-resolution geochemical data from the Viking Corridor, North Sea Basin, that fills a critical gap in published records that span the Early-Middle Jurassic. These records presented here aim to reconstruct paleoredox conditions, track local and global mercury sources, and assess the interplay between the TOAE, global KF-LIP, and the North Sea Dome (NSD).

The expression of the TOAE in the Viking Corridor is not well understood. Moreover, while we understand the role that the NSD played in the tectonostratigraphic configuration of the NCS, the impact on redox conditions during NSD onset and evolution remains unclear. We confirm the TOAE presence with a negative CIE that coincides with the onset of KF-LIP along with elevated Mercury (Hg) and redox-sensitive elements (RSE). Our data also shows a spatial Hg trend across a basinal transect, where proximal settings are elevated in Hg and RSE. In proximal settings, post-TOAE deposits are Hg-enriched across the Early-Middle Jurassic, linked to either pulses of NSD uplift/doming and a major eruption, or enhanced weathering that transported terrestrially-derived Hg into the marine system. RSE enrichment factors suggest a particulate shuttle mechanism acting beneath an oxygen-minimum zone. Distal settings have punctuated peaks of slightly elevated Hg during the earliest Middle Jurassic, suggesting NSD pulses. Together, this work provides insights into the interplay between TOAE, LIP, and Hg-RSE systems during an important transition in the Earth’s biogeochemical history.