OR/15/053 Kilchurn Castle

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Everett, P A, Gillespie, M R and Tracey, E A. 2015. Provenance of building stones in four 'galley castles' in Argyll. British Geological Survey Internal Report, OR/15/053.

Kilchurn Castle is located on a peninsula at the northeast terminus of Loch Awe. It was built on a rocky outcrop, surrounded by marshy land. When the water is high, the castle appears to be on an island.

Layout and building chronology

Kilchurn Castle is comprised of several buildings contained within a ruinous Curtain Wall with cylindrical Towers at the north, south and west corners. The entrance to the inner courtyard is through the ground floor of the five-storey Tower House, located at the east corner. Laich Hall, now ruinous, stood on the inner face of the South Curtain Wall. Additional ranges are located to the southeast, north and northwest facing the inner courtyard. The Southeast Range contained two cellars, loft and chapel. The North and Northwest Ranges contained four-storey barrack blocks. A timeline of construction and alterations for Kilchurn Castle is presented in Table 5.

Table 5 Timeline of construction and alterations in Kilchurn Castle
Information from: RCAHMS (1975) [1]
Date Action Location or masonry element
Mid-15th C Construction Tower House
1475–1513 Construction Laich Hall
Mid-16th C Reconstruction Tower House, upper storeys with turret corbels
1614 Reconstruction Laich Hall, rebuilt and raised two storeys
1616 Construction Southeast Range
1643 Repairs Tower House and Laich Hall
1690–8 Construction North, West and South Corner Towers
1690–9 Construction North and Northwest Ranges
Mid-18th C Abandoned All
1770 Unroofed All
Figure 14 Plans for Kilchurn Castle with periods of construction and alteration. Source: RCAHMS (1975) [1];
pages 230, 233.

Building stones

Kilchurn Castle sits on a small outcrop of hard metamafic-rock (Figure 15a) that forms a small knoll above the surrounding softer metasedimentary rocks of the Ardrishaig Phyllite formation, which have been preferentially eroded. The knoll of metamafic rock on which the castle sits has been quarried on its east side. A sample was collected from the quarried outcrop and a thin section was prepared (Appendix 1). The castle walling commonly contains sub-tabular blocks of variably foliated metamafite, which are similar in character to the stone from the quarry. The quarry probably provided a substantial volume of stone for the castle walling.

Most of the Kilchurn Castle walling stone is variably foliated greenish-grey pyrite-bearing metamafite. Occasional rounded blocks of coarse pinkish granite are present; these are likely to have been field boulders that originally came from the nearby Cruachan Granite Pluton (a granite intrusion).

The coarse sandstone mentioned in Walker (2000)[2] was not encountered in this project.

Decorative stone

Flaggy metamafite

Almost all of the decorative stone in Kilchurn Castle is strongly foliated, greenish grey schistose metamafite (many blocks contain scattered crystals of the iron sulphide mineral pyrite). Most of the dressing stones in all building phases are formed of this material, which is shaped into quoins, windows and door dressings and was used to form structural turret corbels (Figure 15b, c).

Blocks of flaggy metamafite used as decorative stones are more strongly foliated, and therefore more likely to form tabular blocks, than the metamafite used as walling stone, but they may both have been sourced from the same bedrock unit. Both are typical of metamafic rocks found extensively in the Dalradian Supergroup around the north end of Loch Awe.

Some shaped blocks, which may represent re-used decorative stone from previous reconstructions of the castle, are present in later stages of the walling (Figure 15d). Blocks used to form a doorway surround on the top floor of the tower may consist of pyroclastic rock (Figure 15e); thin section examination would be needed to test this hypothesis.

All of the walling and decorative stones used in Kilchurn castle are essentially similar in character throughout all stages of the castle construction.

Figure 15 Decorative stone in Kilchurn Castle.
a – quarried bedrock beneath Kilchurn Castle; looking NNE towards the SE Tower. b – dressed stone blocks around a window opening between the ground floor and first floor of the Keep. c – the Keep. d – random rubble walling showing re-use of dressed blocks within the walling. e – surface detail of a dressed stone block forming the left side of an open doorway on the top floor of the Keep; the stone is weathered (pitted), greenish-grey, foliated metapyroclastic-rock with scattered large crystals of tarnished pyrite.

References

  1. 1.0 1.1 RCAHMS. 1975. Argyll: an inventory of the ancient monuments, Vol. 2 Lorn. HMSO Press: Edinburgh
  2. WALKER, F A. 2000. The buildings of Scotland: Argyll and Bute. (London: Penguin Group.) ISBN 0140 71079 5