Case Study
Tell Ahmar (Til Barsib)
City Wall and Suspected Gate
See also: - Summary page
- Urban Zone - City
Wall & Monumental Architecture - Isolated
Farmstead
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The image above shows a shade plot of electrical resistance
data showing the city wall and a number of adjacent structures.
Magnetic field gradient data has been overlaid as colored contours.
Corelation between the two data sets can greatly aid in their interpretation.
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- Orange - magnetic anomalies
associated with city wall
- Red - resistance anomalies
associated with city wall
- Dark blue - other magnetic
anomalies
- Light Blue - low resistance
anomalies
- Green - high resistance
anomalies
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Mud brick walls are thought
to appear as diffuse low-resistance anomalies, generally
linear. Low resistance anomalies might also be caused by
organically enriched features or a variety of other cultural
or natural features.
High-resistance anomalies
may be caused by concentrations of stone or fired brick.
Where a resistance high is spatially correlated with high
amplitude bipolar (both positive and negative) anomalies,
basalt or fired brick is suspected. Where resistance highs
are correlated with weak magnetic lows, we suspect limestone
to be the origin of the anomaly.
To date there has been no
invasive testing of the geophysical survey results within
this area. The identification of the city wall can be made
with some confidence by interpolation of ground truthing
results and by large-scale patterning in the survey data.
Limited excavation would greatly inform our interpretation
of this data.
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