Printed from the APC web site: navigation and non-essential images removed.
Please view on-line for full content (URL at end of document).
Archived News ~ Week ending Friday 6th February 2004.
Reconnaissance evaluation of 'The Flasks'
An area of pasture known as 'The Flasks’, situated to the northeast of Nosterfield Quarry, has been the subject of archaeological evaluation during the summer of 2003.
Location of The Flasks (dark red) with other investigation areas shaded light red.
The area under evaluation represents an area of about 8 hectares. The Flasks is on the site of a prehistoric lake which became filled with sediment during the early Holocene. Fen peat then developed overlying the in-filled lake. Radiocarbon dating of the early peat suggests the area was no longer underwater by around 8705-8440 BC. It may be that after this, the area was exploited for its natural resources, and finds of knapped flint at the Flasks also suggest this.
Flint recovered from 'The Flasks'
Evaluation programme
The evaluation programme consisted of two phases, the first aimed to map the ground surface by topographic and hachure survey, to map visible earthworks in the field, and model the underlying deposits and lake extent by auger survey. Phase 1 allowed areas of highest archaeological and palaeo-environmental interest to be defined; these were subject to further investigation in Phase 2.
Phase 2 involved the excavation of two trenches, A and B, at locations identified in Phase 1. Trench A was designed to investigate further a sinuous channel (located between S3 and S6 on hachure map), likely to be the result of peat-cutting. Trench B was designed to investigate further an earthwork mound (S1 on hachure map), the origin of which was unclear, but which may have attracted activity as either a small natural island in an otherwise wet or boggy area, or as an artificial mound. Two core holes were additionally taken from targeted locations by Dr Jim Innes and Dr Mairead Rutherford from the Swale-Ure Washlands Project (Department of Geography, University of Durham), to investigate further the sequence of sediment infill.
Augering in progress
Phase 1
Phase 1 successfully mapped the earthworks in the area, and the auger survey showed that underlying deposits at the Flasks become deeper towards the south due to underlying desiccated and humified peat. The northern area of the Flasks tended to have shallower buried deposits, but isolated swallow holes were identified in this area and reached depths of over 1.50m below ground surface.
Phase 2
Trench A, located over the sinuous channel, found peat intact within the channel. This, alongside a change in local geology, suggests the channel is natural in origin and is likely to be an erosion feature. Trench B showed that the make-up of the mound was geological. The layers consisting of a topsoil overlying a geological knoll made of gravels which were tested during excavation. One feature located at the summit of the mound was filled with burnt, scorched and fire-cracked stones. The feature was completely excavated but no dateable material was present. Other stray finds from topsoil included five flint flakes, animal bone and medieval to post-medieval pottery.
Results of pollen analysis from two augers
Results from palynological reports, authored by Dr J Innes and M Rutherford, Department of Geography, University of Durham, have been summarised below. The analysis has been undertaken as part of the Swale-Ure Washlands Project funded by English Heritage as part of the Aggregates Levy Sustainability Fund.
One auger sample encountered the sequence of sediments which had infilled the prehistoric lake; the other samples the sequence infilling an isolated 'swallow hole’ which in itself may have been a small pool.
The lake sequence has been analysed by Dr Jim Innes and, while not yet tightly dated by radiocarbon dating, it has provided environmental evidence from the Late Glacial to early Holocene period from a core measuring 2m in depth. The initial sediment sequence of the pond is characterised by clays and silts some of which contained mollusc shells. These silts and clays represent the silting of the prehistoric lake and this is overlain by peat. Unfortunately, the upper half of the peat deposit is desiccated and not suitable for further study, although the sequence below the desiccated horizon has been suitable for analysis. The earliest silting sequence seems to have taken place during an interstadial (warmer period during an ice age) period when the surrounding area was woodland including birch and willow. This is followed by a Late Glacial stadial (cold period during the last ice age) period when the surrounding area was overtaken by hardy plants forming sedge-tundra landscape. Once the lake had infilled, the temperate Holocene (the period after the last ice age) climate allowed the development of peat over the lake area in which the pollen from a wooded landscape, again including birch and willow, became deposited in the peat. In order for the peat to form, the area must have been waterlogged with pools of water. The extent of the standing water would be affected by long terms trends in climate change, and may also have varied seasonally, possibly being wetter during the winter, and drier during the summer.
The sequence encountered in the swallow hole is similar to the latest peat deposits in the lake in so far as it represents environmental evidence from after the last ice age. Mairead Rutherford has undertaken analysis of the 5m core and analysis shows a wooded landscape made mainly of deciduous (not evergreen) trees. Tree species included birch, oak, lime, alder, elm and hazel and also included pine. At a certain point evidence for tree species drops significantly and this coincides with the presence of pollen from grass, herb, shrub and cereal species. Some aquatic species are recorded such as algae, which may have been living on the surface of the water in the swallow hole.
While radiocarbon dating results have not yet been received, this sequence is similar to the traditional model for landscape change observed elsewhere in Britain. This suggests that, in the immediate Post Glacial period the area was wooded with a mix of tree species, at some point, possibly from the Neolithic, the woodland may then have been deliberately cleared, as suggested by the drop off of pollen quantity from tree species. At the same time, grass, shrub, herb and cereal pollen numbers increase or feature for the first time. This mix of species suggests an open grassland environment with some possible cereal cultivation taking place in areas of woodland clearance.