James Peter & Kousoulakou Maria
University of Liverpool &
Greek Ministry of Culture
Environmental Change in the area of Oropos. A discussion of research questions and methods.
The remains of the pre-Classical settlement of Oropos lie between the hills and the sea, beside the course of one of the intermittent streams that flow across the coastal plain. Neither the level of the sea nor the regime of streams was stable during the Early Iron Age. The people of Oropos could hardly have been aware of a rise in sea level (research by others has shown a rise throughout the Holocene, and of more than 2 m since the Classical period), but the streams were capricious. Revealed in the excavation of the EIA site are flood defences and flood damage, including the deposition of sand and gravel above the level of floors. And worse was to come. At some time, possibly in the second half of the 6th c. B.C., the site disappeared beneath 3 m of mud washed from the valley immediately behind it.
In 2002 we undertook a one-week reconnaissance study of the mud sediments
exposed in the excavations, and of the landforms, sediments and soils in the
hills inland of Oropos and on the coastal plain. The mudflow sediments covering
the site have little bedding and show few changes in style of deposition,
possibly indicating deposition either in one or very few major events. The
valley system that forms the hinterland of the site is cut into thick deposits
of Neogene gravels and clays, the latter having been the source of the mudflow
sediments.
The stream from the valley behind the site is not the only one to have affected the area of the site. A large alluvial fan at the mouth of the Asopos valley forms the coastal plain to the northwest of Oropos. The modern Asopos flows into the sea 4 km from the site, but waters from this river system clearly flowed eastward across the plain at some time to deposit distal sediments of the fan within a few hundred metres of the site.
The research planned for 2004 will address questions concerning geomorphological change on the coastal plain and the significance of change in the hills. The questions, some of which have implications for the wider late Holocene environment of Greece, are:
1. The mudflow: What lies buried beneath it that has not been excavated? When and why did the mudflow occur? Why did the stream change from a manageable force to one that engulfed the site in mud? What triggered the hillslope instability that caused the mudflow? Could it have been a shift in amount or intensity of rainfall, a very severe deluge, an earthquake, an intrinsic threshold in the development of the valley system, a change in land use, or a combination of causes? Do major erosion events date from the same time elsewhere in Greece or were circumstances in the Oropos area unique?
2. The Asopos drainage system: did the Asopos River flow through the site?
3. The lagoon: can its sediments yield evidence of coastal change and a chronology of deposition by the Asopos River? This is a tectonically unstable region: is there evidence of earthquake-triggered tsunamis that could have hit the site?
We propose, in 2004, to carry out a programme of coring (to a maximum of 10 m) through the sediments in the area of the site and in the lagoon, and to sample the range of soils in the valley catchment inland of the site. The corer will be a machine percussion gouge, which has the advantage of being (necessarily) manoeuvrable and of taking good sediment cores, but the drawback of being relatively light and incapable of penetrating coarse gravel. We trust that perseverance will bring success with the coring. In addition to logging sediment stratigraphy, we shall sample sediment units for mineral magnetic, particle-size and selected chemical analyses. Similar analyses will be made of the catchment soils in order to determine whether precise sediment sources can be identified. Any dateable organic materials will be collected from the cores, and any artefacts recorded.
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