Conférence GM & ED Gaïa

The IODP South Atlantic transect: Low-temperature Ridge Flank Contributions to Global Biogeochemical Cycles and Archives of Changing Global Conditions

By Rosalind COGGON (University of Southampton, UK)

14:00 amphi 23.01, campus Triolet, Université de Montpellier

Take part in the online conference (ID : 978 5251 9118)

Throughout its life the ocean crust is a key boundary between Earth’s interior and the oceans/atmosphere. Hydrothermal circulation of seawater-derived fluids through the cooling and aging crust results in chemical exchange between Earth’s interior and oceans and atmosphere, playing an important role in long-term biogeochemical cycles.

I will present an overview of how scientific ocean drilling experiments across ridge flanks contribute to our understanding of the processes that control ridge flank hydrothermal exchanges, the role these exchanges play in global geochemical cycles, and the extent to which they record and respond to wider changes in the Earth system.

The South Atlantic Transect (IODP Expeditions 390C/395E/390/393) was designed to recover the upper crust and overlying sediments across the western flank of the slow-spreading Mid-Atlantic Ridge to investigate hydrothermal aging and microbiological evolution of the ocean crust, and the paleoceanographic evolution of the overlying South Atlantic. I will focus on how the recovered crustal cores have revealed that the extent and duration of ridge flank hydrothermal carbonate precipitation are influenced by crustal architecture, which is strongly influenced by spreading rate. Consequently, ridge flank hydrothermal contributions to the long-term planetary carbon cycle depend on the global length of slow-, intermediate-, and fast-spreading ridges and the age distribution of the ridge flanks, which have varied significantly throughout the Phanerozoic.

 

 

 

Dr Rosalind COGGON is Royal Society University Research Fellow. Her research focuses on the role of fluids in the formation and evolution of the ocean crust, with a particular emphasis on quantifying the thermally driven chemical exchanges between the aging ocean crust and the overlying oceans and their influence on global geochemical cycles.

She is heavily involved in scientific ocean drilling, serving as co-lead editor of the 2050 Science Framework: Exploring Earth by Scientific Ocean Drilling.