5. Environmental Evidence by I. López-Dóriga

A total of seventeen samples were taken during the two phases of fieldwork. Four samples from the watching brief and thirteen samples from the excavation were taken from a range of deposits associated with modern industrial activities and were processed for the recovery and assessment of environmental evidence, primarily charred plant remains and charcoal.

The purpose of this assessment is the evaluation of the quality of plant remains preserved at the site and the potential for further analysis to address specific site archaeological issues and to provide archaeobotanical data valuable for wider research frameworks.

The size of the samples varied between 10 and 40 litres. The bulk samples were processed by standard flotation methods; the flot retained on a 0.25mm mesh, residues fractionated into 5.6mm and 1mm fractions and dried. The coarse fractions (>5.6mm) were sorted, weighed and discarded. Large flots were split into fractions and the large (>4mm) fractions were subsampled for the assessment of environmental evidence. After recording the volume and the assessment of the subsamples, made of industrial debris, the remainder of the subsampled fractions were discarded. The smaller fractions (<4mm) of the flots were scanned using a stereo incident light microscopy at magnifications of up to x40 using a Leica MS5 microscope for the identification of environmental remains. Different bioturbation indicators were considered, including the percentage of roots, the abundance of modern seeds and the presence of mycorrhizal fungi sclerotia (e.g. Cenococcum geophilum) and animal remains, such as earthworm eggs and insects, which would not be preserved unless anoxic conditions prevailed on site. The preservation and nature of the charred plant and wood charcoal remains, as well as the presence of other environmental remains, is recorded in Appendix 8 of the archive report [PDF]. Preliminary identifications of dominant or important taxa are noted below, following the nomenclature of Stace (1997) for wild plants, and traditional nomenclature, as provided by Zohary and Hopf (2000, tables 3, page 28 and 5, page 65), for cereals. Abundance of remains is qualitatively quantified (A*** = exceptional, A** = 100+, A* = 30-99, A = >10, B = 9-5, C = <5) as an estimation of the minimum number of individuals and not the number of remains per taxa.

Results

The flots were generally large but made of lightweight industrial debris type slag or clinker or very small. There were low numbers of roots and modern seeds that may be indicative of stratigraphic movement and the possibility of contamination by later intrusive elements. Little environmental evidence was preserved, comprising a few charred plant remains and wood charcoal fragments. No evidence of remains preserved by waterlogging was observed.

The charred plant material was poorly preserved and comprised the remains of cereal grains and a few wild plants.

The analysis of the environmental evidence has no further potential. The few remains of cereals and wild plants recovered might indicate the existence of some crop-processing by-products (cereal grains) in the environment.

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