2. Background to Block Lifting

As previously mentioned, block lifting has been used in the past at Star Carr in order to develop the technique and to allow for finer-scale laboratory excavation of the deposits (Mellars 1998). In 1989, one cubic metre of material was removed from the section edge of Trench A by cutting into the section and inserting a sampling chamber with sharpened edges, a device constructed by engineers. The chamber was driven into the deposits using screw-operated acrow-jacks and then guillotined along the back using a steel sheet driven down by a sledge hammer. Metal ropes were then attached to the chamber and it was lifted using a tractor, the whole being wrapped in polythene sheeting and taken to Cambridge on an open-loader truck. In the laboratory the block was moved with a fork-lift onto a pallet. Excavation was carried out using illuminated magnifying lenses and material was retained for further sieving or flotation. All potentially informative components of the sample (wood and other macrofossil plant remains, etc.) were recorded on graph paper and photographed, and all were given finds numbers and bagged for further analysis. Unfortunately only the very top part of the block was ever excavated and the Mesolithic finds level, where antler (cut in half during the lifting process) was known to be located, was never reached (Paul Mellars pers. comm. 2008). The block was left in the Cambridge Archaeology stores but was moved when the room became a thin-sectioning laboratory in 1993. When the block was removed, it was noted that the floor where the block had first stood was permanently damaged, leaving a scar in the linoleum (Julie Boreham pers. comm. 2009). Normally, this would not be expected, but as is noted here, oxidation of the peat deposits at Star Carr is resulting in extremely high acidity which must have been the cause of the damage to the floor. In 2003 the block was removed using a JCB and disposed of (Jessica Rippengal and Julie Boreham pers. comm. 2009), presumably because it had deteriorated.

Block lifting was used more successfully on Mesolithic material elsewhere in the Vale of Pickering in 1983 when a small block measuring 300 x 200 x 150mm was lifted from the site of Seamer K (David 1998). Microliths were found eroding from a machine-cut section associated with degraded wood. The block was lifted in order to excavate carefully, in conjunction with environmental sampling, what was suspected to be a composite tool. The fully excavated group consisted of 16 backed blades. Unfortunately, owing to the poor preservation of the wood it was not possible to establish whether this represented a cache or a composite tool; however, a sample of the wooden material obtained a radiocarbon estimate of 8210±150 BP (HAR-6498), a rare example of a securely dated microlithic assemblage. In this case the block lifting was needed because of the precarious situation of the potential composite tool, eroding from a section, and it allowed the secure excavation of this material.

Block lifting has also been used on Mesolithic sites beyond the Vale of Pickering. In 2003, at the inter-tidal Mesolithic site of Goldcliff East, Martin Bell used the technique for excavating sites A, B and D, which were particularly difficult to access because the tides enforced only short windows of opportunity (Bell 2007, 34). He had previously used this technique at Westward Ho! (Balaam et al. 1987) and there it involved dividing each 1m square into 16 blocks, each 250mm². Each block was cut and loosened, a four-sided metal tin was placed around it, and each block was lifted, then wrapped. The blocks were transported back to a Community Hall, where they were reassembled into the 1m² in a divided wooden frame with 16 compartments, and excavation proceeded on dry land. Finds were recorded in 3-D, as on the site. Although this procedure took considerable effort, the benefits were clear: artefact recovery was better and footprints in the mud were visible that might not have been observed on site. In addition, more sediment was available for sieving. The main disadvantage was that small features such as stakeholes might potentially have been missed, but it was felt that in this circumstance the advantages outweighed the drawbacks.

Another example of Mesolithic block lifting comes from March Hill in the central Pennines. Here two 0.5 x 0.5m blocks were taken and excavated by CC (Conneller nd; Spikins 2003). The first was removed in 1993 and excavated as part of a student practical project to investigate vertical spatial clustering of micro-debitage. Though this was successful, the project was extremely time-intensive and similar results could be achieved in the field through a small-scale sieving programme. The project would have been unfeasible without student labour. The second block was more significant. It was removed in 1994 from March Hill Top (trench B). This block contained a Mesolithic stone-built hearth, which had been uncovered on the last day of the 1994 season. Since this area was regularly raided by flint collectors (indeed this was considered to be a particular collector's 'patch'), it was decided that the safest procedure would be to lift the hearth and excavate it at leisure. This proved to be a wise precaution since this area was indeed dug into by a collector before the team's return in the 1995 season. The micro-excavation of this feature was extremely successful, revealing two phases of use and demonstrating the association of a rod microlith with one of these phases. However, this micro-excavation was again very time-intensive, taking several weeks to complete. Given enough time and decent weather conditions, similar results would have been achievable in the field. Furthermore, removal of the hearth from its surrounding context made it more difficult to interpret. While the removal of the block undoubtedly led to the hearth being recorded for posterity (rather than being destroyed) and the entire exercise was worthwhile in investigating the potential of alternative methodologies, overall the increased amount of time/money needed was not matched by an equivalent increase in the amount of information produced.

Block lifting has also been used on Danish Mesolithic sites and particularly for burials, e.g. at Nederst (humans and dogs), Vængesö and Holmegård on Jutland (Søren Andersen pers. comm.). In addition, in the Vedbaek area of Zealand, a number of other burials have been block lifted including two whole graves from Bögebakken, which were taken to the National Museum: one of these, a child grave, was not possible to excavate in the field and an adult grave was transported to the Museum for display purposes (Albrethsen and Brinch Petersen 1976, 6). The mass grave of eight individuals at Ströby Egede was also lifted en bloc and transported to Copenhagen for further excavation at the National Museum (Brinch Petersen 1987). Two dug-out canoes from Tybrind Vig and one from Lystrup have also been removed in a block for further excavation in a laboratory (Andersen 1996; Fig. 2).

Figure 2
Figure 2: Boat from Lystrup being lifted for further examination in the laboratory (Andersen 1996, fig. 20, 28).

Block lifting is, of course, not restricted to the Mesolithic period. For instance, at West Heslerton blocks from some of the graves found in the Anglian cemetery were lifted for further analysis in the laboratory (Haughton and Powlesland 1999, 20-21). Many of these graves contained fragile assemblages, often with mineral-preserved or mineral-replaced organics. The method developed as the excavations went on, but generally the blocks were isolated on a pedestal and then wrapped in cling-film and plaster bandage before being sealed with plaster or polyurethane foam. Once indoors, they were X-rayed and dismantled. In this case the lifting of the block was essential because very fragile materials such as textiles could be retrieved in this way. The main problem was the length of time taken to dismantle the blocks, which took nearly six years of work after the completion of the excavation.

In summary, block lifting has some advantages in certain circumstances and particularly when there are physical constraints, such as at Goldcliff East, or very fragile finds, such as at West Heslerton. But block lifting can also be extremely time-consuming and costly and these factors must also be weighed up. This article will examine these factors and present a verdict on whether block lifting is a viable method for the site of Star Carr.


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Last updated: Thu Mar 25 2010