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ABINGDON ARCHAEOLOGICAL GEOPHYSICS

 

 

 

 IRAN

In 2006-9 we assisted the Gorgan wall project and Edinburgh University in surveying forts and other features associated with this wall which is in north east Iran

Here is a photo of Arman, who did much of the magnetometry, standing over the  mud brick feature in fort 4 of the Gorgan Wall. Full details may be found in the publication of this site in the journal Iran. It would however appear that mud brick here may be easier to see magnetically than it is by excavation as the mud bricks could only be detected by the experienced excavators below approx 1metre. Above that the bricks had decayed but were detectable magnetically.

magnetometer on Gorgan wall in Iran

Here is the magnetometer survey. This shows 3 rows of virtually identical rooms with a largely empty area at the top of the illustration. The highest readings are shown in red. These are mainly fairly recent funerary monuments made from fired brick which will have come from the Gorgan wall itself.

magnetometry survey of Sassanian fort

                             Magnetometry survey of Fort 4 on the Gorgan Wall, Iran

                               

 The survey was carried out using 30 metre grid squares and these were aligned to be at an angle to expected features in order to maximise the chances of finding anomalies.

We were fortunate in that the organisers of the project had the vegetation cut down before we surveyed. This enabled the magnetometer sensors to be kept less than 15 cms from the ground surface. We were then rewarded by being able to locate mud brick walls which gave a typical anomaly strength of 2nT above that of the surrounding soil.

We were also fortunate in that this fort interior has been little damaged, if at all, by ploughing. Whilst root action had made the top 1.5metres of the mud brick walls virtually unrecognisable to the human eye, the soil from which they were made had remained in situ. The individual bricks were visible below 1.5m depth and the bottom of the wall which was excavated was 3.6m below the present ground surface.

This fort is one of the largest of those which are on the Gorgan wall which is a defensive wall built from fired brick and dated to the 5th century AD.

Our 2007 season located many rows of small gullies and mud brick remains in another fort and in 2008 we located a town to the north of the Gorgan wall.