The Loch Awe Syncline (Argyllshire)

Abstract

T he district described in the present paper forms portion of the low-coastal region of Argyllshire, and presents few physical difficulties to the investigator. There are, however, other difficulties, resulting from the fact that igneous and sedimentary schists occur together here in about equal proportions, and have been alike subjected to a system of small-scale isoclinal folding; moreover, though lavas are well represented, fully half the igneous schists are sills, and so are of little use for stratigraphical purposes. Under the circumstances, it is not surprising that progress has been slow. Macculloch, writing in 1819 [1, p. 292\, did himself less than justice, for he seems to have decided against the igneous origin of any of the schists of the region, erecting his Chloritic Formation to include the whole assemblage. In regard to structural matters he was more fortunate, for he gave a clear account of the lie of the rocks in the southern part of the district, where he located [l, pp. 288-89\. In nature, of course, the line is rather vague, being more correctly designated as a narrow belt, where both bedding and cleavage are often extremely steep or vertical. This belt runs from the eastern shores of Loch Sween, north-north-eastwards through the southern end of Loch Awe. For some miles to the south-east of its course the prevalent dip of both bedding and cleavage is towards the north-west, and vice versá . There is also a tendency for the angles of inclination to be higher near the central belt