IODP Expedition 381 Corinth Rift: FEC Co-Chief Scientist Duties and Post-Moratorium Research

Lead Research Organisation: University of Southampton
Department Name: School of Ocean and Earth Science

Abstract

The discovery of plate tectonics in the 1960's has provided geologists with insight into the causes of earthquakes and the continued re-organisation of the continents. An important part of plate tectonic theory is continental rifting and breakup, the process that begins the process of breaking apart a continent and ultimately can result in the formation of a new ocean. There are many continental margins on Earth where we know rifting has acted in the past and these margins are the source of much of the world's oil and gas resources, but there are limited places where we can witness the active processes that presently characterise the formation of a rift valley. Of the relatively small number of places on Earth where the process of continental rifting is just starting, the Gulf of Corinth, Greece stands out as a rare location of earthquake activity, high rates of the plate being split apart and a record of the rifting process contained in the sediments now filling the rift basin. Therefore it holds vital clues as to how a tectonic plate stretches and splits into two.

The Corinth Rift has been studied for several decades, with scientists investigating its rift deposits and active fault traces exposed on land. But much of the activity is hidden below the inland sea of the Gulf of Corinth and in order to investigate this part of the rift, researchers have used marine geophysics to image the faults and sedimentary layers below the seafloor. They have also sampled the shallowest sediments using coring techniques. The has allowed us to see how faults have developed to create the basin and cause it to gradually subside as the rifting process evolves. We can also see how the sediment, eroded from the land surrounding the basin, has gradually filled the subsiding basin and records the movement of the faults through time. What has been lacking is direct sampling of these sediments over a significant part of the time since rifting began. This would enable us to determine how old the different sedimentary layers are and therefore how fast the faults are moving and how quickly the rift is opening and changing. Sampling and investigating the plants and animals living within and around the basin would also tell us the environment of the basin - was it a marine sea, a freshwater lake, or a series of river and delta systems and how has this changed as the rift has developped? These flora and fauna would also tell us about the local climate of this part of the Eastern Mediterranean and how this related to changes in the global climate in the last 1-2 million years, and how climate might have affected how and how much sediment was eroded and transported into the basin.

The Integrated Ocean Discovery Program (IODP) will be drilling 3 boreholes in order to sample these rift basin sediments to answer the problems and questions raised above. This method, using a drillship, is the only way these sediments can be accessed. Approximately 32 scientists of a wide range of geoscience disciplines will analyse the cores and log data (which give information on the physical properties of the sediments) together over a period of 3 months offshore and onshore and then over a period of 3-4 years after the expedition. In addition, McNeill will take some of the drilling results and compare them with the already collected marine geophysical data to get a better idea of how fast faults are slipping, the basin is opening up, and how fast it has been subsiding, which can tell us how much the continental crust of the plate has thinned since the start of rifting. The results will be very relevant to understanding the potential for earthquake hazards in the region (how fast faults move is a major control on earthquake potential) and also to understanding how and where hydrocarbon resources collect within the earliest and deepest part of a rift system.

Planned Impact

1. Who could potentially benefit from the proposed research over different timescales?

Geohazards: The Expedition results will have a direct bearing on the assessment of hazards from earthquakes and triggered tsunami and slope failure (in particular submarine) from slip on active Corinth rift faults. The results will provide much improved constraint on the slip rates of these active faults, and may also provide direct information on the frequency of large slope failures or on the timing of earthquakes from liquefied layers or "seismites". The key dataset will be high resolution absolute chronology for the stratigraphy which can be translated using geophysical data to faults to determine their displacement history. Therefore the results will benefit regional populations, including areas of coastal and high population density around the Gulf of Corinth and in the Athens metropolitan area.
Natural resources: The results will be provide quantified information on how rifts open and evolve, rates of subsidence and thermal evolution of an early rift basin, history of faults linking and developing networks that control fluid flow, and how sedimentary deposits start to build up within a rift basin. These factors are all relevant to the petroleum industry which has interest in the earliest phase of the rift process. But in active exploration regions, these deeper parts of the rift are often difficult to evaluate directly. Therefore the Corinth Rift provides an analogue for more mature rift systems (failed continental rifts and rifted margins), but with directly sampled data.
Outreach: Outreach efforts and wide broadcast of the results of the Expedition will impact the general public, in terms of increasing understanding of Earth science processes, plate tectonics, rifting processes, earthquake hazards, and the climate of the Eastern Mediterranean, and of scientific ocean drilling. These are areas of science that capture the public's interest in part due to their societal relevance. Public awareness is important for several reasons: general scientific education of the population; understanding of the importance of scientific research for all; encouragement of the next generation to study science and take up scientific careers; and the need for awareness of natural hazards and of the origin of our natural resources.

2. How might the potential beneficiaries benefit?

Geohazards: Results from the expedition, namely fault slip rates and any evidence for history of earthquake shaking, will be shared with Greek collaborators for entry into regional fault databases. We will work with our Greek colleagues to ensure these results reach policymakers working on mitigation and reduction of natural hazard risk in the region.
Natural resources: Several of the science party and collaborators on this proposal have direct connections to the petroleum industry. By using these links and through presentation of results at industry-academic conferences such as AAPG and potentially within industry-related publications (AAPG Bulletin, Basin Research), we will work to raise awareness of the results within the petroleum industry.
Outreach: Outreach is a major component of any IODP Expedition, including 381. The ECORD Science Operator (ESO) outreach team are planning press conferences, regular reports and blogs during the expedition broadcast online, social media reporting, a Reddit Ask Me Anything session, video coverage of expedition activities, and promotion of the expedition at visitor attractions and museums in the UK and beyond. Target audiences include the media, general public, the wider scientific community, policymakers (including in Greece, as related to geohazards) and educators and science communicators. The Co-Chief Scientists will work the with ESO Outreach team to deliver this outreach programme, along with the rest of the expedition science party.
 
Description Recent results published in McNeill et al (2019), Scientific Reports, demonstrate the environmental history of the Corinth Rift Basin and the combined influence of tectonic subsidence, sediment supply and sea level on changing conditions and faunal/floral populations. The results indicate the timings and rates of the processes and also that sediment flux into the basin is 2-7 times larger during glacial periods than interglacial periods due to changes in vegetation cover around the flanks of the basin.
Exploitation Route They are the first long and high resolution record of the conditions in a young rift basin and can be used to see sedimentary and environmental conditions at this stage.
Sectors Energy,Environment

 
Description Talk at UKIODP annual meeting on results from IODP Expedition to Corinth Rift 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Invited presentation on initial research results from first ocean drilling in a young active rift
Year(s) Of Engagement Activity 2018