Aerial view of the Thinia valley

Research Plans for 2021

In 2021 we will focus our research plans on the Thinia valley (highlighted in the aerial photograph above, looking north). The area is crucial to the Odysseus Unbound theory that we’re testing. It is the presumed site of the marine channel that Strabo describes as having once separated the Paliki peninsula from the rest of Kefalonia.

Our aim is to get and examine evidence that will allow us to determine if the channel existed and was there at the time of Odysseus, in the Late Bronze Age (c.3000 years ago).

Summary

Research ProjectOutcomeCost
Long Electrical Resistivity Tomography (ERT) across the Thinia valleyA detailed 3-D picture of the geology under the valley floor right down to modern sea level. Combined with existing gravity survey data it will give us the best possible understanding of the very complex way the valley has been filled by one or more major landslides. Read more…£20,000
Optically Stimulated Luminescence (OSL) dating of buried walls in the ‘wooded triangle’OSL dating reveals when buried rocks (including man-made features) were last exposed to light. This will give us a date for the landslip that buried the walls under the ‘wooded triangle’. Read more…£5000
Cosmogenic Radionuclide Exposure (CRE) dating of back scarps of eastern mountainsCRE dating reveals how long rock has been exposed to cosmic rays. This will give us a date for when the eastern mountainside broke off to crash down as a massive landslip, exposing a new cliff face. Hopefully the OSL and CRE dates will be similar! Read more…£10,000
Field surveys in Thinia valleyDetailed mapping of previously identified faults in the valley hillsides should tell us how different sections of rock moved in the landslides. We may find surface evidence of marine sediments thrown up by the landslides. Together, we will get a more complete picture of how the valley was filled. Read more…£2750
Analysis of Fugro sediment coresIf we find evidence for layers of disruption and deformation caused by landslides we will be able to correlate the dates and extent of the landslide events. Read more…£5000
Exploratory archaeological investigationsWe will collaborate with the Greek Ephorate of Antiquities on Kefalonia and the National Technical University of Athens to support their investigations of a Mycenaean tomb site on Paliki. Read more…£10,000
TOTAL COST£52,750

Background to the formation of the Thinia valley

Our research in the subsurface of the valley has already revealed new evidence that shows that a marine channel existed some 400,000 years ago, something that is not apparent from surface geology.

Significantly, we now know from analysis of the marine core sediments we drilled in 2018 that sea levels rose after the last Ice Age (in the past 10,000 years) to a level high enough to flood such a deep valley, potentially creating a marine channel again.

Crucially, our evidence also shows this happened before the Late Bronze Age, so making a channel at the time of Odysseus much more likely.

A core of sediment is carefully carried to be wrapped and boxed.
A core of sediment is carefully carried to be wrapped and boxed ready for analysis in the lab onshore.

The Roman geographer Strabo described an intermittent channel some 2000 years ago. And we know a massive landslip blocked the southern exit of the valley to a depth of some 180m.

The 2021 Research Projects in detail

These fundamental questions will be addressed through a combination of geological and geophysical methods for which we seek your financial support.

The field mapping, geophysical data acquisition, use of other innovative dating methods and the sampling and analyses of the core material that is now housed in Edinburgh will enable Professors John Underhill and Peter Styles to address and answer the remaining questions and produce a definitive answer about the existence and date of Strabo’s Channel.

Surface geology map of the Thinia valley
Surface geology map of the Thinia valley (field survey by Professor John Underhill).

We plan to collaborate with a team from the National Technical University of Athens (NTUA) to carry out an extensive Electrical Resistivity Tomography (ERT) survey of the valley.

The NTUA scientists will use new state-of-the-art equipment, that can look up to 200m below the surface (ie. below current sea level).

750m long cables stretched across the valley will send electrical signals through the ground to measure its resistance.

We’ll be combining the ERT data with data from gravity surveys we carried out in 2020; the results of a new analysis by Professor Peter Styles of the data from an earlier Fugro gravity survey and the data from Fugro’s aerial EM survey of the valley.

Between them, gravity and ERT can distinguish between the dense limestone bedrock, the looser landslide material and the softer sediments that are found in the bed of a marine channel.

This holistic, multi-technology approach will create a 3-D picture of the underlying geology of the Thinia valley and should reveal whether any evidence for a channel remains.

Electrodes are hammered into the ground every 2m along the resistivity line
Electrodes are hammered into the ground every 2 metres along an ERT line.
2020 07 23 i8 DSC 014a Thinia Gravity Research
Professor George Apostolopoulos (NTUA) making a gravity measurement in the Thinia valley, July 2020.
View of the "wooded triangle"
Looking west across the southern end of the Thina valley towards the “wooded triangle”

Landslip material from the eastern mountains swept across the valley to cover ancient walls on the western side.

It is visible as a tongue of landslip material that we call the “wooded triangle”.

We plan to excavate the buried walls and use a technique called Optically Stimulated Luminescence (OSL) to date when they were covered by the landslide. OSL is an advanced technique that has proved tremendously useful in dating buried ancient structures.

The analysis will be carried out by one of the world’s leading OSL experts, Dr Jean-Luc Schwenninger, the Head of the Luminescence Dating Laboratory at the School of Archaeology at Oxford University and we are very grateful for his collaboration.

jlschwensmall
Dr Jean-Luc Schwenninger, Oxford University, in the OSL laboratory

When stones are buried, low-level natural radiation causes electrons to become trapped in defects in the crystal lattice structure of quartz grains in the rock.

The number of trapped electrons builds up steadily over time.

In an OSL lab, the electrons are exposed to a special light (optically stimulated) which releases them as photons of light (luminescence).

Measuring the amount of light released gives the date when the stones were buried.

CRE dating is a widely-used technique in the study of landscape changes over time periods from as short as ten years to tens of millions of years.

When the massive landslide happened, a huge chunk of the mountainside to the east of the Thinia valley broke away, crashed down and spilled across the valley.

That sudden event left behind a newly-exposed cliff face.

As soon as a rock face is exposed it begins to be bombarded by cosmic rays, high energy charged particles from outer space.

The particles smash into the atoms of the rock creating new isotopes of the chemical elements that make up the rock.

Thinia Rotation
Approximate outline of the massive segment of mountainside that we believe dropped as a single block to choke the southern exit of the valley.

By measuring the concentration of these new isotopes, the scientists can determine a date for when the rock was first exposed to daylight.

Professor John Underhill will carry out a finely detailed field survey of the valley to hunt for clues about how the landslide(s) happened and what might have triggered it (them).

We’ll be looking at geological faults identified in earlier surveys. They are the boundaries where sections of rock have moved past each other and their topography should give us clues to how the landslide(s) moved.

We’ll also be searching for signs of marine sediments on the surface that might be evidence for the marine channel. Such sediments may have been raised up in the valley due to the violence of, and rotation induced by, the landslide(s).

Thinia drilling rig
Fugro drilling rig in the Thinia valley

The geoscience company Fugro drilled sediment cores in a number of locations during their sponsorship of the Odysseus Unbound project. Those cores are now stored at Heriot-Watt University where they can be properly analysed by Professor John Underhill and others.

When a landslide hits water it can trigger a tsunami. The violent wave churns up the top layers of sea floor sediment, creating a distinct layer of disturbed sediment in the geological record.

We intend to sample the sediments in the Fugro cores to look for signs of disruption and deformation due to landslides.

We will also look for any evidence for any sudden marine invasion due to earthquake-induced tsunamis, similar to that identified by German scientists (Willershäuser et al, 2013) in cores they drilled in the Livadi Marsh.


Willershäuser, T., A. Vött, H. Brückner, G. Bareth, O. Nelle, M. J. Nadeau, H. Hadler and K. Ntageretzis 2013. Holocene tsunami landfalls along the shores of the inner Gulf of Argostoli (Cefalonia Island, Greece). Zeitschrift für Geomorphologie 57, 4, 105–138.

There is evidence of Late Bronze Age (Mycenaean) occupation of Paliki in tombs found dug into soft limestone on the peninsula.

All the known tombs have been robbed in antiquity but some artefacts exist and are held at the Argostoli museum (currently closed after damage during the 2014 earthquake).

2016 10 06 c DSC 013a New Vouni tomb
Mycenaean tomb on Paliki

In 2021/22 we will continue our fruitful collaboration with the Greek Ephorate of Antiquities for Kefalonia and NTUA to support their work surveying and excavating a tomb site on Paliki.

Appeal for sponsorship and donations

These advanced geophysics techniques are expensive, even though we conduct them in collaboration with academic colleagues from Greece and elsewhere.

We estimate our plans for 2021 will cost some £52,750. But they are carefully chosen to give us the best chance of answering the questions at the heart of the Odysseus Unbound project.

Please contact us if you’d like to sponsor all or part of the research. Commercial or individual sponsors are both welcome. Please email us at [email protected] for more details.

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