Excavation

Date 10 June 2009 - 17 July 2009

Event ID 605407

Category Recording

Type Excavation

Permalink http://canmore.org.uk/event/605407

NR 72010 09289 One of the key pieces of evidence from the early Neolithic in the northern Irish Sea zone are chambered cairns. Examples have been excavated in northern Kintyre, but these excavations were over 50 years ago, and a range of new research questions and techniques have developed in the intervening period.

Blasthill chambered cairn sits close to the summit of Blasthill, an upland area surrounded by agricultural land.

Since 2006, over 50 fields have been fieldwalked and flint obtained from every field investigated, including a number of large lithic scatters (DES 2006, 2007 and 2008). We have also conducted a detailed walkover survey of the whole of Blasthill which has revealed a large number of previously unrecorded features. Survey and trial excavations have confirmed the presence of Bronze Age cairns, houses and field systems (DES 2007 and 2008). Environmental work has revealed a 4m peat sequence in a bog next to the chambered cairn (DES 2006).

In 2009 two trenches were opened across Blasthill chambered cairn. Before excavation a detailed measured

survey was made of the monument and 1:50 and 1:20 plans produced. The work undertaken 10 June–17 July

2009 demonstrated a complex constructional sequence. Environmental and dating samples were taken and a range of Neolithic and Bronze Age artefacts recovered.

Trench A (5 x 5m) targeted the forecourt area of the monument, with the aim of looking for potential in situ

prehistoric activity associated with use and abandonment of the monument. The original RCAHMS and our pre-excavation survey seemed to indicate that there was considerable infilling in the forecourt area. On removal of the topsoil we came down onto stone infilling. This context clearly abutted the orthostats of the façade and therefore represents the final use and abandonment of the monument. Finds from this context included a hammerstone and two pieces of flint, one of which was burnt.

Removal of the stone infilling revealed a paved surface, consisting of red sandstone slabs. A single bead, of a jet-like material, was found on the paving. Beneath the paving were two silt deposits and underlying this was a dark charcoal-rich deposit that may represent the clearance of vegetation (through burning), prior to the monument’s construction. Removal of the blocking revealed the full 1.2m height of the façade stones. Between two of the façade stones coursed walling was found, consisting of one large igneous stone near the base and a series of smaller thin sandstone slabs (see photograph). This coursed walling clearly pre-dates the blocking.

The kerb and cairn of the monument in this trench were constructed directly on bedrock. Distinctions in the

construction of the cairn strongly suggest a long sequence of construction and modification. The kerb stones did not appear to be load-bearing, but seem to have been placed against the cairn and chocked into place. It is also suggested that the façade stones were added onto a pre-existing cairn, and that the façade was also remodelled extensively throughout its life.

Trench B (13 x 3m) was opened across the body of the cairn, incorporating half of the side chamber, with the aim of understanding the constructional sequence of the monument. The location of this trench allowed the excavation of c50% of the chamber deposits. Chamber 2A (outer compartment) contained a fill of stone in a heavily bioturbated matrix. One large stone of this fill covered a complete early Neolithic pot, which appeared to have been deposited whole and flattened in situ. Other finds included numerous pot fragments including a large fragment of decorated early Neolithic pottery, a hammerstone and quartz. A large number of tiny tooth enamel fragments were subsequently found via wet sieving. The entranceway into this chamber was blocked

by an infill of stones, a result of the construction of the long cairn. Chamber 2B (inner compartment) contained

a single fill. This 0.5m deep fill was homogeneous due to heavy bioturbation. Finds included six pottery fragments (Carinated Bowl pottery), a number of small beach pebbles and quartz. A number of tiny tooth enamel fragments were also found via wet sieving. Additional sherds of pottery and a flint knife were found on the surface of the cairn just outside this chamber.

The body of the cairn comprised large stones in a substantial matrix, indistinguishable from the topsoil. Consultation with a soil scientist suggested that this matrix was the result of the bioturbation of large quantities of turf. This explains the lack of substantial stone cairn material within the monument, originally interpreted as robbing. There seems little doubt that a considerable component of the cairn was made from

turf. To the N, a well-preserved kerb defines the edge of the cairn. Beyond this kerb a compacted spread of stones abut the outer face of the kerb. The stone spread appears to have been deliberately laid at some point after the construction of the kerb.

The southern edge of the cairn was hard to define, marked only by a spread of cairn material. The contour on this side of the cairn indicates two breaks of slope, neither of which is natural. At the top of the first break of slope was the start of a mass of large cairn stones which seem to be the remains of a primary phase of construction. These stones form an arc just beyond the chamber entrance and seem to demark the edge of a primary cairn. This primary cairn appears to have been sub-circular in shape, with the chamber at its core. This

has parallels with sites in Dumfries and Galloway, notably Mid Gleniron I and II. The lower break of slope represents a later phase of cairn construction and modification associated with the incorporation of the primary cairn within the longcairn. On the surface of this later phase of construction small abraded fragments of coarse ware pottery were found. Stratified material suitable for dating was retrieved from both trenches in order to secure the constructional sequence of the monument.

Archive: RCAHMS (intended)

Funder: The Kintyre Antiquarian Society, Robert Kiln Charitable Trust, the Royal Archaeological Institute and the University of Central Lancashire

Vicki Cummings and Gary Robinson – University of Central Lancashire/Bangor University