- Start date: 1 June 2018
- End date: 30 November 2018
- Funder: NERC
- Value: £20,137
- Primary investigator: Dr Richard Collier
Rift basins evolve through subsidence on the downthrown side of faults and uplift of the rift flanks, on the upthrown side of the main rift faults. As a result, slopes in the surrounding landscape evolve through time in response to growing rift-related topography, but in competition with erosion that also occurs through time.
The higher the slope angles (the higher the relief), the higher are the associated rates of erosion for any given climatic setting. Rates of sediment supply to the basin therefore provide a record of rift structural evolution over the life of an active rift. Sediment supply also interacts with rates of tectonic subsidence within the rift, and with any fluctuations in sea (or lake) level through time, to determine whether the basin is underfilled with sediment or alternatively gets progressively filled and ultimately overfilled with sediment.
The Corinth Rift is currently underfilled, with water depths in excess of 800m, but there may have been periods of preferential infilling and other periods of basin deepening, for given tectonic subsidence rates, depending on the shorter-term rates of sediment input to the basin.
The prediction of associated sedimentary geometries within rift basins is an important aspect of hydrocarbon exploration and so a better understanding of these processes could reduce uncertainties in commercial exploration efforts. Studying a young and active marine continental rift system (of which there are only few in the world) means that we can date the sediments accurately, using a variety of absolute and relative dating methods.
Over the last several ice ages, we also already have an accurate record and understanding of sea level changes and of palaeoclimate changes in the eastern Mediterranean region. This means that the new cores from Expedition 381 will allow detailed quantification of variations in sedimentation rates over the last few hundreds of thousands of years.
This will allow us to establish for the first time the magnitude of variations in sediment erosion rates and transport into the rift during this interval, and how these variations in sedimentation rates relate to short-term climate fluctuations, over time periods of only thousands to tens of thousands of years. This will aid our understanding of how future changes in climate may impact upon sediment transfer from the onshore landscape to the offshore in a wider range of sedimentary basins.
ImpactThe work targets fundamental research on tectono-sedimentary interactions and rates of sedimentary process. However, this will provide important input to understanding and modelling of sequence stratigraphic geometries in modern and ancient rift basins worldwide.
The interpretation of these geometries is critical in hydrocarbon exploration in syn-rift settings. An improved understanding of these tectonic/base level/sediment supply interactions may reduce interpretation uncertainty and lead to reduced risk estimations in drilling decisions.
The proposer regularly trains and presents to oil company geoscientists and a generic talk on the aims of Exp. 381 is already planned - for presentation to the Dhahran Geoscience Society in Saudi Arabia. Results will however not be released until the end of the moratorium period.
The Expedition 381 team has already run a number of outreach and public awareness events, most notably through Greek national news coverage of the onset of Exp. 381 drilling and through events facing the Athens Department of Geology and Geoenvironment.
A blog is running and has been promoted for School students and others to follow. More education and outreach activities are planned for the onshore science party in Bremen. More generically, IODP has regular outreach activities associated with major international research conferences such as EGU, AGU and GSA.