Tag Archives: GPS

THaWS 2016. A Late Start and Sediments Beyond the Temple of Ay and Horemheb

So another season of survey and augering is under way at Thebes. The Theban Harbours and Waterscapes Survey has, for the past 5 years, been using geoarchaeological and geophysical survey to study the changing floodplain of the river Nile, and the dynamics between the ancient harbours and waterways and the Theban temple complexes on the West Bank and Luxor and Karnak temples. In 2015 the survey work focused on the areas around Kom El Hetan and the Ramesseum, with Electrical Resistivity Tomography profiles and auger locations running from the edge of the floodplain to the modern course of the Nile. In addition an area survey was conducted over the mounds at Malqata, associated with the harbour of Birket Habu. This year the season is focussing its attention on the floodplain between the colossal seated statues of Amenhotep III and his huge ceremonial lake (Birket Habu), immediately to the east of the funerary temple of Ay and Horemheb.

 

Sunrise over the Nile floodplain as viewed from the West Bank

Sunrise over the Nile floodplain as viewed from the West Bank

 

After a slight delay at the start of the project for permits, the work commenced on 19th January. Reconnaissance of the area to the east of the temple, looking for a route across the floodplain for both ERT and auger locations, was conducted last autumn and walked over by the team as we waited for our paperwork to be completed.

The aim of the transect of boreholes (hand augering and a percussion coring) and geophysical survey (Electrical Resistivity Tomography (ERT)) is to understand the geoarchaeological history of the floodplain in this area of Thebes. We are using our RTK GPS to establish the location of the ERT profiles and to survey in borehole locations during the course of the work.

Carolin Johansson (Medelhavsmuseet, Stockholm) setting up the GPS base station

Carolin Johansson (Medelhavsmuseet, Stockholm) setting up the GPS base station

 

Carolin conducting GPS survey along an ERT traverse

Carolin conducting GPS survey along an ERT traverse

 

As the ERT survey was set up and continued to collect data across the floodplain from west to east, the team also attempted some GPR. However, issues with the equipment meant that no survey could be completed, and this will have to wait until later in the season. The augering got off to a flying start, with boreholes starting immediately east of the temple of Ay and Horemheb and supported by the ERT profile data. The coring and hand augering both revealed the variation in the sediments from the desert edge, running east across the floodplain, with different depths of silts and sands.

 

Ben Pennington (University of Southampton) removing sediment from the auger head assisted by Mohammed

Ben Pennington (University of Southampton) removing sediment from the auger head assisted by Mohammed

 

Dominic Barker (University of Southampton) gets to grips with a corer sample

Dominic Barker (University of Southampton) gets to grips with a corer sample

 

Jan Peeters (Utrecht University) recording sediments from Auger site 71 in the West Bank floodplain with the Theban hills in the background and assisted by Moustapha (auger) and Hassan (sitting) and onlooked by Zazou, who is working on the ERT profile behind them

Jan Peeters (Utrecht University) recording sediments from Auger site 71 in the West Bank floodplain with the Theban hills in the background and assisted by Moustapha (auger) and Hassan (sitting) and onlooked by Zazou, who is working on the ERT profile behind them

 

Willem Toonen (Aberystwyth University) working at auger site 67 with Youssef and Ahmed in front of the funerary temple of Ay and Horemheb with Medinet Habu immediately south (in the background)

Willem Toonen (Aberystwyth University) working at auger site 67 with Youssef and Ahmed in front of the funerary temple of Ay and Horemheb with Medinet Habu immediately south (in the background)

 

The work with the augers was matched by the pace of the ERT, with resistivity data being collected along a traverse completed in four separate profiles, measuring over 2.7km in length. This traverse is located to complement the borehole data and the ERT data collected in the traverse to the east of the Ramesseum in 2014 and 2015, allowing comparison of the varying resistivity values from both locations.

 

Zazou, Ahmed, Reis Alaa and Sumara take a well-earned rest while the ERT collects data

Zazou, Ahmed, Reis Alaa and Sumara take a well-earned rest while the ERT collects data

 

As with many field projects, in some cases the work in the field marks only a part of the overall effort. Once the geophysical survey data is collected, and the auger samples are bagged or put into plastic tubes, the hard work of data processing and study of the augered samples begins. After a week of work, the whole team was called on to soak, sieve and pick through the sediments, weighing and measuring the different inclusions in the sediment to glean as much information about the nature and chronology of the floodplain sediments as possible. This data will be compared with the geophysics to help ground-truth the data and provide crucial information of the potential date of different deposits.

The preliminary data is already pointing to some interesting results on the deposition of sediments deposits, and their relationship with the West Bank monuments. There is still lots of processing and studying to be done!

 

Bird’s eye view of clasts from sieved samples drying and then being sorted from the borehole sediments

Bird’s eye view of clasts from sieved samples drying and then being sorted from the borehole sediments

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The Portuslimen Project. Geophysical survey at Tarragona, and the constraints of modern urban areas

Over the past few months of field survey, work has swung around to a series of projects lined to Roman ports in the Mediterranean. In June and July I headed back for a season of excavations at Portus, and in August and September geophysical survey at the site of Ephesus in Turkey (more on this in a future post). In October and November work has commenced on a geophysical and topographic survey of the Roman port area of the town of Tarragona in Catalonia, Spain. The work, together with that of Ephesus, forms part of the Roman Meditteranean Ports (RoMP) project, or Portuslimen (http://portuslimen.eu/). A component of this project involves the survey of a number of port sites, to understand the form and extent of these sites, and help analyse the ways in which they may have functioned through time. The work at Tarragona is being conducted in collaboration with colleagues from l’Institut Català d’Arqueologia Clàssica (ICAC).

 

The modern port of Tarragona, with its harbour, docks and factories

The issue with Tarragona is that the development of the town and port spans from the pre-Roman period, to the establishment of the Roman town in the third century BC, to Late Roman and Visigothic settlement in the 6th, 7th and 8th centuries, and later Islamic influence. Over this time the town and its port expanded and contracted, and archaeological deposits were buried under fluvial deposits from the Francolí river to the west of the port. Later post-medieval expansion of the town, particularly in the 19th and 20th centuries saw much of the Roman and later port built over, and a new harbour constructed over the remains of the ancient port. The aim of our survey is to attempt to locate significant structural remins of the Roman port and harbour through intrusive methods. The good news is that a number of areas in the city have been excavated in the past 40 years, which helps in the location of the survey to gain as much as possible from the efforts. The bad news is that, due to the modern town plan, many of the survey areas are constrained by modern buildings and infrastructure. Thus our work has to use some specific techniques to conduct survey in the areas that are available. This includes topographic survey and location of survey grids using RTK GPS and total station survey, and use of GPR and ERT along streets and in plazas to map buried remains.

Set up of the GPS and GPR by the University of Southampton team in the Placa dels Carros

Set up of the GPS and GPR by the University of Southampton team in the Placa dels Carros

 

The GPS base station collecting static data for the survey

The GPS base station collecting static data for the survey

 

Fortunately for the University of Southampton team, the open plazas of the town provided sufficient space for static data to be collected by the GPS base station, and for a series of preliminary stations to be established using the GPS. Where the streets became narrow a total station was used to establish further stations in a traverse around the port area of the town.

Geophysical survey s far has focused on 500MHz GPR, propagating 3-4m below the modern street level to find the buried archaeology. In some of the streets in the northern part of the port area, particularly along the roads close to the Roman baths and theatre a number of walls and other features are visible. As the survey progresses southwards, however, modern infrasructure such as manhole covers, and the nature of the made-up ground close  to the modern harbour, make the results more difficult to interpret. The restrictions in terms of spatial coverage have also provided a challenge in terms of data interpretation.

Total station survey in one of the streets of Tarragona

Total station survey in one of the streets of Tarragona

 

500MHz GPR survey in one of the plazas

500MHz GPR survey in one of the plazas

 

To better understand the geoarchaeology of the site we have been applying Electrical Resistivity Tomography (ERT) to record both archaeology and deeper deposits in the town. The main constraint with this is that the paved areas of the town preclude the use of survey probes (these cannot be dug through cement and Tarmac). Thus we have had to adapt using a system of electrode copper conductors and a conductive gel. Most surfaces will allow an electrical current to be passed through them, but asphalt and Tarmac act as insulators, meaning that for the ERT to work long stretches of cement pavement need to be surveyed.

A conductor formed from crocodile clips, wire and pipe end copper usually used for plumbing.

A conductor formed from crocodile clips, wire and pipe end copper usually used for plumbing.

The ERT profile being conducted adjacent to the Roman theatre

The ERT profile being conducted adjacent to the Roman theatre

 

In spite of our initial misgivings, the conductors and gel, with the ERT equipment, have proved to work very well indeed. The profile alongside the Roman theatre has revealed a number of areas of walls and rubble aligned adjacent to the excavated theatre remains. The team hope to conduct a long profile of ERT in the southern part of the modern port which, together with the boreholes of Ferreol Salomon, will investigate the nature of the harbour deposits.

The survey work is being conducted until 15th November, and there are many features of the topography of the ancient harbour that remain to be discovered, including the line of the Roman seafront and mole.

The bay to the east of the port

The bay to the east of the port

 

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