| Title: |
Geophysical Survey at Land south of Halifax Road, Pendle |
| Series: |
Wessex Archaeology unpublished report series
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| Downloads: |
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wessexar1-516828_213562.pdf (2 MB)
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| Biblio Note |
This report was uploaded to the OASIS system by the named Publisher. The report has not been reviewed by the relevant HER. The report has been transferred into the ADS Library for public access and to facilitate future research.
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| Licence Type: |
ADS Terms of Use and Access
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| DOI |
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| Publication Type: |
Report (in Series)
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| Abstract: |
The magnetic data for this project were acquired using a non-magnetic cart fitted with four SenSys FGM650/3 magnetic gradiometers. The instrument has four sensor assemblies fixed horizontally 1 m apart allowing four traverses to be recorded simultaneously. Each sensor contains two fluxgate magnetometers arranged vertically with a 0.6 m separation and measures the difference between the vertical components of the total magnetic field within each sensor array. This arrangement of magnetometers suppresses any diurnal or low frequency effects.
The gradiometers have an effective resolution of ±8 µT over ±1000 nT range. All of the data are then relayed to a CS35 tablet, running the MONMX program, which is used to record the survey data from the array of FMG650/3 probes at a rate of 20 Hz. The program also receives measurements from a GPS system, which is fixed to the cart at a measured distance from the sensors, providing real time locational data for each data point.
The cart-based system relies upon accurate GPS location data which is collected using a Leica Captivate system with rover and base station. This receives corrections from a network of reference stations operated by the Ordnance Survey and Leica Geosystems, allowing positions to be determined with a precision of 0.02m in real-time and therefore exceed the level of accuracy recommended by European Archaeologiae Consilium recommendations (Schmidt et al. 2015) for geophysical surveys.
Data may be collected with a higher sample density where complex archaeological anomalies are encountered, to aid the detection and characterisation of small and ephemeral features. Data may be collected at up to 0.01 m intervals along traverses spaced up to 0.25m apart. The geophysical survey has identified several areas in the south and east of the site containing anomalies which may be associated with mine workings, however other explanations such as agricultural, general land management, manholes and rubbish disposal are also likely.
In the south-west of the site structural features, likely foundations and associated demolition material have been detected within a wider area of rubble. It is likely these are the remains of structures recorded in historical OS mapping. Whilst not the properties typically exhibited by a mine shaft, as there would normally be a larger area of magnetic disturbance, there is the potential for this being a building associated with mine workings. Other origins such as an agricultural building are also likely.
In the east of the site a highly magnetic large square structural feature has been detected. It is possibly the concrete foundations of a large building or other structure such as a large footing, or cap, related to a mine and its entry. Other modern origins related to landscaping or a building are possible however further investigation would be needed.
Several large ferrous responses have been detected in the south of the site, with two close to a recorded mapped mine shaft. Whilst these anomalies have the potential to be a small metal mine shaft covers, given the continued use of the site including landscaping and drainage, these anomalies are likely manhole covers or large pieces of modern metallic waste.
An area of highly magnetic rubble or disturbed ground has been detected in the very east of the site. This may be related to former mine works, equally however, this may be caused by waste from nearby allotments or housing developed around the perimeters of the site.
Two areas of highly magnetic responses have been detected in the north and west of the site. In the north are the remnants of allotments built between 1955 and 1965-67 and demolished between 1965-67 and 2000, as recorded in OS historical mapping and satellite imagery. |
| Author: |
Lydia Jones
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| Publisher: |
Wessex Archaeology
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| Year of Publication: |
2023
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| Locations: |
| County: |
Lancashire |
| Parish: |
Brierfield |
| Country: |
England |
| District: |
Pendle |
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Grid Reference: 386040, 436510 (Easting, Northing)
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| Subjects / Periods: |
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| Identifiers: |
| OASIS Id: |
wessexar1-516828 |
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| Source: |
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| Relations: |
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| Created Date: |
15 Aug 2023 |
