ABINGDON ARCHAEOLOGICAL GEOPHYSICS

                                            IRAN

In 2006  and 2007 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 magnetometery, standing over the  mud brick feature which was located by this method. It would however appear that mud brick here may be easier to see magnetically than it is by excavation.

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 areas containing fired bricks which are the walls around the fort and areas where these have been used in recent times to construct funerary monuments.

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.