Title: |
River of Life II: Written Scheme of Investigation for geophysical surveys |
Series: |
DigVentures unpublished report series
|
Downloads: |
digventu1-349366_190275.pdf (3 MB)
:
|
Download
|
|
Licence Type: |
ADS Terms of Use and Access
|
DOI |
|
Publication Type: |
Report (in Series)
|
Abstract: |
An area of 8.3ha be subject to geophysical magnetic survey at Hurst Water Meadow, 17.8ha at Clifton Meadow, and 37.7ha at Church Farm.
To carry out the magnetic survey Phase Site Investigations Ltd will use a MACS (multi-sensor array cart system). The MACS utilises eight Foerster 4.032 Ferex CON 650 gradiometers with a control unit and data logger. The gradiometers are carried on a non-magnetic cart and usually have a spacing of 0.5m, although other intervals can be adopted. Readings are generally taken generally at between 10cm and 15cm intervals, depending on the speed the cart is pulled at. A MACS utilises an RTK GNSS system which means that survey grids do not have to be established. Instead an area is surveyed over a series of continuous profiles and the position of each data point is recorded using an RTK GNSS system. The survey will be referenced direct to Ordnance Survey (OS) National Grid and so temporary survey stations (wooden stakes) will not be established unless specifically asked for prior to the commencement of the survey.
Data was collected on zig-zag profiles along the full length or width of a field, although fields can be sub-divided if they are particularly large. Marker canes were set-out along field boundaries at set intervals and these are used to align the profiles. The survey profiles are usually offset from field boundaries, buildings and other metallic features several metres to reduce the detrimental effect that these surface magnetic features have on the data. The Foerster gradiometers have a resolution of 0.2nT but the stability of the cart system significantly reduces noise caused by instrument tilt and movement when compared with a traditional hand-held gradiometer system and the increased data intervals provide a higher resolution data set. The sensors have a range of ± 10,000nT.
The data was imported into a gridding and interpolation software package, such as Archaeosurveyor (DW consulting) or Surfer (Golden Software). A plot of the data was exported from the gridding software. This will be imported into AutoCAD where it was displayed relative to the available map detail. The survey has provided evidence for possible archaeological activity in the Clifton Meadow field, in the form of several series of positive linear / curvi-linear responses and trends. A Roman settlement is present to the south of Clifton Meadow and a trackway, of presumed Roman date, has been identified which leads towards the survey area. Some of the responses could relate to a continuation of this trackway and other, possibly related, features. No anomalies that could be clearly related to archaeological features / activity were identified at Church Farm or Overy Mead.
Most of the areas are dominated by responses relating to natural features / variations, probably including gravel / alluvial deposits and palaeochannels. These responses have created a variable magnetic background which has made it difficult to differentiate between individual responses, which could be related to infilled features or other potential archaeological activity, and responses caused by natural features variations. As such the majority of isolated responses within these areas have not been shown on the interpretation and it should be noted that if discrete archaeological features are present it is unlikely it would be possible to differentiate between responses related to discrete features and the responses related to natural features / variations.
The majority of the remaining anomalies identified by this survey relate to modern material / objects, agricultural activity and geological / pedological variations. |
Author: |
Hannah Russ
Brendon Wilkins
|
Publisher: |
DigVentures
|
Year of Publication: |
2019
|
Locations: |
District: |
Stockton-on-Tees |
Parish: |
Stockton-on-Tees, unparished area |
Country: |
England |
County: |
Durham |
Grid Reference: 445789, 519349 (Easting, Northing)
|
Grid Reference: 445679, 519419 (Easting, Northing)
|
|
Subjects / Periods: |
|
Identifiers: |
OASIS Id: |
digventu1-349366 |
|
Source: |
|
Relations: |
|
Created Date: |
06 Jul 2023 |