| Title: |
Geophysical Survey at Pump House |
| Series: |
Wessex Archaeology unpublished report series
|
| Downloads: |
|
wessexar1-513670_211948.pdf (4 MB)
:
|
Download
|
|
| Licence Type: |
ADS Terms of Use and Access
|
| DOI |
|
| Publication Type: |
Report (in Series)
|
| Abstract: |
The cart-based gradiometer system used a Leica Captivate RTK GNSS instrument or equivalent, which receives corrections from a network of reference stations operated by the Ordnance Survey (OS) and Leica Geosystems or equivalent. Such instruments allow positions to be determined with a precision of 0.02 m in real-time and therefore exceeds European Archaeologiae Consilium recommendations (Schmidt et al. 2015).
The detailed gradiometer survey was undertaken using four SenSys FGM650/3 magnetic gradiometers spaced at 1 m intervals and mounted on a non-magnetic hand-pushed cart. Data were collected with an effective sensitivity of ±8 µT over ±1000 nT range at a rate of 100 Hz, producing intervals of 0.02 m along transects spaced 4 m apart. A long linear feature has been detected in the north of the site which is considered to be the extension of a ditch previously detected in both geophysical survey and trenching in 2015. It is considered likely to be a late Iron Age or Romano-British field boundary given the dating evidence found near to it’s very eastern extent in 2015. Several other much smaller curvilinear anomalies have been detected across the north of the survey area however it is less certain whether these are of archaeological origin. Pit-like features were detected in the north. Given the amorphous anomalies’ similarity in shape and signal to an anomaly determined through trenching to be a small-scale quarrying pit in 2015 containing Romano-British pottery, it is possible that these anomalies are also small quarry pits. Other small discrete pit-like features have been detected across the site which may be archaeological pit features associated with agricultural or small-scale quarrying activity, although given a lack of a discernible pattern a geological origin cannot be ruled out.
An old field boundary and the former Strettington Lane End road have been identified in the north of the site. An area of enhanced variation in the underlying geology has been detected in the north of the site. Numerous magnetic trends have been identified in the north of the site. Some of these relate to modern ploughing trends, whilst others do not have a clear origin. Ferrous responses and areas of magnetic disturbance have been detected that are likely relate to telegraph poles, the building of the A27. The remaining anomalies are thought to be modern, relating to services, drains and extant field boundaries. |
| Author: |
Lydia Jones
|
| Publisher: |
Wessex Archaeology
|
| Year of Publication: |
2023
|
| Locations: |
| Parish: |
Boxgrove |
| Country: |
England |
| District: |
Chichester |
| County: |
West Sussex |
|
Grid Reference: 489329, 106828 (Easting, Northing)
|
|
| Subjects / Periods: |
|
| Identifiers: |
| OASIS Id: |
wessexar1-513670 |
|
| Source: |
|
| Relations: |
|
| Created Date: |
03 Jul 2023 |
