This section, simplified from Butler (1982), shows the larger-scale geometry of the Pipe Rock duplex (but see the detail from the field!). CST - Creag Shomhairle Thrust (as seen in its type area), MT - Moine Thrust.
The ridge of Conamheall is composed of imbricated Pipe Rock together with local slices of the stratigraphically younger Fucoid Beds and Salterella Grit. In detail this structure is a series of intraformational and intrabed duplexes that have thickened the stratigraphy considerably (Butler 1982a). The original stratigraphic thickness of the rocks forming these structures was just 75m, above a floor thrust that glided just above the base of the Pipe Rock. The burrows within the Pipe Rock retain circular sections on bedding surfaces and are generally perpendicular to bedding in profile. Consequently thrust sheet stacking was achieved with almost no internal distortion. This style, while typical of the Pipe Rock duplexes of the Foinaven site, is in marked contrast to those found in Heilam, for example, part of the adjacent Eriboll area.
The Conameall outcrops contain the most continuous exposures of thrusts in the British Isles. The geometries visible at outcrop are best appreciated via the photographs. Balanced cross-sections provide an estimate for original width of the 6 km of Pipe Rock section on Conamheall of 54 km, a figure used for crustal balancing in NW Scotland (Butler and Coward, 1984).
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