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Geoscientists like to reconstruct the past so they can better understand climatic and geological events today. For example, gradual closure of the marine corridors linking the Atlantic and Mediterranean prior to the formation of the Gibraltar Strait is known to have caused vast water- and salt-level changes in the Mediterranean Sea, and an accumulation of oil and gas over millions of years.
“Marine corridors or ‘gateways’ play a critical role in the exchange of water, heat, salt and nutrients between oceans and seas, which also influences regional and global climate conditions,” explains Rachel Flecker of Bristol University. “But to truly understand the phenomenon and the extent of its impact on climate over time, we needed more data about ancient marine gateways.”
Decades of research into the exact timing of this closure, the geometry of the corridors and the flow and exchange through them had barely scratched the surface, according to the EU-funded MEDGATE training network, which she led. The problem had been one of scale and the difficulty of gathering surface and subsurface data without sufficient skills, funds and equipment.
Total commitment by both academia and industry during the four-year programme meant the necessary tools and people were available to deliver 10 interdisciplinary projects exploring marine ‘gateway exchanges’ in unprecedented detail. Findings revealed the sensitive relationship between changing climate and saline levels during the Miocene period, 5 to10 million years ago, as well as the petroleum potential of the region.
The project’s emphasis on practical training and sharing field results was critical in helping to address what MEDGATE’s industrial partners described as “declining skills and expertise” in recent graduates.
New theory on a ‘Salinity Crisis’
The research focused on two marine gateways: the Rifian (Morocco) and Betic (Spain) corridors that linked the Mediterranean with the Atlantic. As these two ‘fossil gateways’ began to close, the Mediterranean experienced massive salinity fluctuations leading to around 6 % of global ocean salt being deposited on the Mediterranean’s sea floor in an event known as the Messinian Salinity Crisis.
MEDGATE’s findings have upended long-held theories on what happened during this critical event, and when. Evidence now suggests that the Gibraltar Strait was still open during the Salinity Crisis, thus supplying Atlantic water to the Mediterranean for much longer. This insight has important implications for oil and gas exploration in the region.
MEDGATE has also been fruitful ground for new climate models to emerge. Several of the trainees have quantified and compared different aspects of Mediterranean freshwater levels and salinity information embedded in rocks to reconstruct the patterns of exchange between Mediterranean sub-basins over a 20 000-year climate cycle. Their findings challenge accepted ideas about the timing and nature of the exchange through the corridor and the volume of freshwater involved.
“This has wide implications on water density and the formation of permanent ice sheets on and around the north pole – which, in turn, feeds into current climate change research geared towards understanding the drivers of major climate shifts,” explains Flecker.
Front-loaded training and outreach
MEDGATE put the expertise of 29 geoscientists from the oil industry and academia to the task of training 10 researchers in the early stages of their careers. A “strong ethos” of cross-disciplinary collaboration was the key success factor, according to Flecker.
The training element was front-loaded both to ensure the researchers had the skill-set needed for the initial phase of each programme, and to give them time to develop expertise in a chosen topic. This know-how could then be shared and leveraged to fill skills gaps identified in the industrial partners.
One researcher, hosted by MEDGATE partner Repsol, an oil company, was offered full-time employment following her secondment. Several participating PhD researchers have taken up post-doctoral and permanent lectureship positions at prestigious academic institutions worldwide. Others have gone on to use their technical skills in different industries.
Several major international research drilling initiatives inspired by MEDGATE’s work are currently led by project participants. And through high-level events and publications, the project’s scientific findings are continuing to pique interest in geoscience academic circles and in the oil and gas exploration business.