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Mineral magnetic profiling of archaeological sediments
Author(s) -
Linford Neil
Publication year - 1994
Publication title -
archaeological prospection
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.785
H-Index - 38
eISSN - 1099-0763
pISSN - 1075-2196
DOI - 10.1002/1099-0763(199411)1:1<37::aid-arp6140010105>3.0.co;2-1
Subject(s) - alluvium , excavation , geology , archaeology , sediment , floodplain , natural (archaeology) , magnetic survey , bioturbation , magnetic anomaly , paleontology , geography , cartography
The commercial extraction of mineral aggregates from a 140 ha site at Yarnton, Oxfordshire instigated a continuing programme of archaeological evaluation in advance of the eventual destruction of the site. It was hoped that geophysical survey, particularly rapid gradiometer coverage, would amplify the information recovered from both aerial photographs and trial excavation. Unfortunately, results from those areas of the site on the Thames floodplain proved disappointing and initially were believed to have been hampered by more recent alluvial overburden. Subsequent area excavation revealed a wealth of archaeological remains from the early/ mid‐Neolithic to the late Bronze Age and a significant variation in both the depth and distribution of the alluvial deposits. This study aims to investigate the local contrast in magnetic behaviour between samples recovered from excavated archaeological features and the surrounding natural sediment; initially concentrating on a series of detailed magnetic measurements made on fractionated soil samples from two pit‐type features. The study confirmed that despite a marginal contrast in magnetic susceptibility a distinguishable magnetic signature was evident within the anthropogenically modified samples and that a combination of measurements, including artificially induced remanent magnetization, provided the greatest degree of discrimination from natural sediments. The results of the detailed investigation were then applied to a more rapid analysis of bulk soil samples from a wider range of archaeological contexts, by examining a variety of samples from a site where there appeared to be little or no magnetic contrast between anthropogenically modified features and the surrounding natural sediments.