1.6 Assessment of Geophysical Survey Data
1.6.1 Introduction 112. The Site is located approximately 2.6km to the west of Bramford, Sussex and 6.45km to the WNW of Ipswich city centre. The proposed development area lies adjacent to an existing electrical substation; a total of 24.4ha was surveyed (Figure 25.14).
113. The Site comprises four arable fields and a small area of a pasture field to the west of Bullenhall Farm, near Bullen Lane. The survey areas are defined by field boundaries on the most part with some of the southern and eastern extents defined by the limits of the proposed development. The Site lies within an area of undulating relief with the height rising from around 45m above Ordnance Datum (aOD) towards the edges of the site to a little over 55m aOD towards the centre. No watercourses are recorded running through the Site but a number of unnamed streams are recorded nearby that flow into the River Gipping further to the east.
114. The soils underlying the Site are likely to be a mixture of typical calcareous pelosols of the 411d (Hanslope) association and typical stagnogley soils of the 711t (Beccles 3) association (SSEW 1983). Soils derived from such geological parent material have been shown to produce magnetic contrasts acceptable for the detection of archaeological remains through magnetometer survey.
115. The detailed magnetometer survey was conducted using a Bartington Grad601-2 dual fluxgate gradiometer system. The survey was conducted in accordance with English Heritage guidelines (English Heritage 2008b).
116. The geophysical survey was undertaken by RSK in 2013. The data was provided to Wessex Archaeology to be reprocessed and reinterpreted. Full details of their methodology used can be found in their survey report (RSK 2013) but a summary of their methodology will be outlined below.
1.6.2 Method 117.
Individual survey grid nodes were established at 20m x 20m intervals using a Leica 1200 RTK GNSS instrument, which is precise to approximately 0.01m and therefore exceeds English Heritage recommendations (English Heritage 2008b).
118. The magnetometer survey was conducted using a Bartington Grad601-2 fluxgate gradiometer instrument, which has a vertical separation of 1m between sensors. Data were collected at 0.125m intervals along transects spaced 1m apart with an effective sensitivity of 0.03nT, in accordance with English Heritage guidelines (English Heritage 2008b). Data were collected in the zigzag method.
Preliminary Environmental Information April 2014
East Anglia THREE Offshore Windfarm Appendix 25.1: Potential Archaeological Receptors Page 34
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145