By unexpected good fortune and against all odds, we have been able to start our field research this summer!
Gravity Surveys
A team from the National Technical University of Athens (NTUA), led by our long-time collaborator, Prof. George Apostolopoulos, has been carrying out detailed Gravity Surveys in various locations in the Thinia valley.
It’s our hypothesis that the valley follows the course of a marine channel that once separated the Paliki peninsula (Ithaca) from the rest of Kefalonia. Our evidence suggests the channel was filled in by a massive land slip at the southern end as well as by more conventional smaller landslides.
Gravity surveys measure the tiny changes in the Earth’s gravitational pull caused by differences in the density of the underlying rock. The result is a map of the valley’s geology. To work out what happened,.we can combine the data with the results of other geoscientific investigations, such as the boreholes drilled in the valley in 2011.
Fugro gravity survey: a new analysis
This work builds on an earlier gravity survey carried out by the geoscience company Fugro during their sponsorship of the project. It was recently reanalysed by Prof. Peter Styles.
His research revealed structures that can be interpreted in two ways.
They might be the folded layers of the ancient bedrock formed when Africa collided with Europe many millions of years ago, in which case no channel could have been possible.
Toe thrusts
Or they might be evidence of “toe thrusts”, where the overlapping layers of rock are pushed upwards by a major tectonic event.
This would be consistent with the evidence we have found for a massive land slip at the southern end of the valley.
Subtle signs of what may be a buried channel
Peter’s analysis also revealed subtle but encouraging signals suggestive of a deep boundary between rock layers of very different densities. This potentially might be the original bottom of the marine channel. The gravity surveys by the NTUA team are designed to shed more light on both these intriguing mysteries.
Further important data analysis
Over the summer we’ll also complete the analysis of additional samples from the marine sediment cores we drilled in the Gulf of Argostoli.
And we’ll also be using sophisticated new imaging and mapping software to look much more closely at several key sites.
