ABINGDON ARCHAEOLOGICAL GEOPHYSICS

SAMPLE REPORT 

Reports are usually sent in draft electronically and followed up with a printed copy. This also contains a compact disc with the report and the data saved in various ways to enable it to be further processed at a later date.

Please note that locational detail has been omitted to seek to protect the site. 

(title) LONG MEADOW, NOWHERE, NO COUNTY. 

(authors) R. Ainslie ARICS AIFA

                A. Another

(contractor) Abingdon Archaeological Geophysics

(client)     Mr Someone

(report reference number) NOWH 230904

(date)   xx September xxxx 

Abstract

Magnetometery and earth resistance surveys located a rectangular anomaly approx 17m x 17m with an area of high magnetic contrast within it. This is interpreted as a tile kiln with its stoke hole on its eastern side. The presence of Roman tile on the site indicates that it is of that period. 

Introduction

The site is located  at grid reference SOXXX XXX

A scatter of tile ,including deformed waster tiles, was located by Mr xxxxxx whilst walking his dog who then asked for the survey to be carried out.

The objective of the survey was to see if any structural remains could be located.

Magnetometery and earth resistance surveys were carried out.

This was because the overburden was thought to be shallow enough for these techniques to produce results. The resistivity survey was to look for building and structural remains which may have been invisible to magnetometery if the soil type proved to be unsuitable for that method.

Methods

Weather – dry

Crop - wheat stubble

Geology - Oolitic limestone 

Survey area – An area of 60 x 60 metres

Magnetometer Survey

Date– xxSeptember xxxx

Equipment – Bartington Grad 601/2 magnetometer in gradiometer configuration

Line spacing   1m

Reading spacing  0.25 m

Line direction – west – east. Start NW corner.

Grid size – 30x30m     

Number of grids – 4

Relationship of grids   1  4

                                2   3 

Processing – ArcheoSurveyor software

Resitivity Survey

Date -xx September xxxx

Weather – showers

Equipment - CIA/TR Systems resistivity meter

Electrode configuration – Twin electrode

Line direction – west – east. Start NW corner.

Mobile Probe spacing – 0.5 m.

Reading spacing  - 1m

Grid size – 30 x30m

Number of grids 3

Relationship of grids   1

                                2   3 

Processing – TR Systems software 

Magnetometery 

Here is the unfiltered survey result – hopefully the programme you use should enable you to click onto it to produce handles to enable it to be enlarged.

Here is the processed version:- 

The processes were:-

Processes:     6

  1   Base Layer

  2   Clip at 3 SD - prevents the plan from being dominated by very high or low readings as these are often caused by modern water pipes.

  3   De Stagger: Grids: 01.asg 02.asg 04.asg 03.asg  Mode: Outbound Inc: -2 -removes an error which can happen if the button to indicate that a line of data is being collected is not pressed exactly on time. Many people find that the Bartington system tends to have a half metre stagger although the reason for this is not known.

  4   Clip at 2 SD

  5   Interpolate: Match X & Y. This inserts additional data points to make p for the fact that 4 readings are taken per metre along the lines but the lines are a metre apart.

  6   Zero Mean Traverse: Threshold 2 SDs .This seeks to correct problems caused by the sensors not remaining balanced during a survey. the sensitivity of the equipment is such that some balancing errors and drift is likely to occur on most surveys.

Here is the greyscale plot:- 

Here is the resistivity plot 

Light colours are higher resistivity indicating walls or similar drier features. 

Here are the magnetometery and resistivity plots combined. This time the colour scheme for the resistivity has been reversed to stop the light colours of the resistivity walls counteracting the dark colour in the mgnetometery. 

Location plan and information 

This would normally be  provided but is not included here in order to safeguard the  site.

Grid reference  of survey grid (approx)

North west corner DD  2233 4455

North east corner 

South west corner

South east corner 

Interpretation Plan

RESULTS 

The enclosure around the high magnetic anomaly has a high magnetometery reading and low resistivity compared with the natural background indicating that it could be made from tile or brick or is itself burnt.  

There are other high spots to the north west of the main area which could be features filled with lots of waste fired ceramic.

The resistivity also hints at other enclosures but these are not definite and could be of geological origin.

Whilst magnetometery has located a 15mx15m enclosure with a large amount of burning, the resistivity has added some detail to this and there are indications of internal supporting walls running north south within the enclosure.

The speckled area going north east from the possible kiln is probably the spread of waste material near the surface.

CONCLUSION

There appears to be a main kiln with a square enclosure around it with its firing access to the east and other ceramic filled or burnt features to the north west of the kiln.

However, whilst there is a lot of burning there and tile wasters on the surface, the size of the enclosure is, at 15m x 15m, almost as large as the combined size of the 6 Roman tile kilns at Holt near Chester.

There were many pieces of Roman roof and flue tiles on the field surface including over -fired wasters which indicates that it is of Roman date.

The survey therefore achieved its objectives. Whilst the magnetometery identified the  burnt areas, the enclosure and the waster scatter, the resistivity helped to define the kiln structure. Ideally resistivity should take place at a 0.5m sample interval to give further definition to the kiln structure before more work takes place.

Acknowledgements

We would like to thank the landowners for allowing us access.

References

As far as we are aware this site is previously unrecorded.

Reference to geological map 

Reference to The pottery Kilns of Roman Britain  RCHM,1984

Other

Please send this to your local inspector of Ancient Monuments and County Archaeologist when you no longer consider this information to be confidential.

Please let me know if you wish this to be kept confidential for longer than 3 months from the date of this report.