Geology of the Quernmore area : 1:10 000 sheet SD55NW : part of 1:50 000 Sheet 59 (Lancaster)

Abstract

This report describes the surface geology of the 1:10 000 Series sheet SD 55 NW, part of the 1:50 000 Series sheet 59 (Lancaster). Detailed descriptions of the geological sequence encountered in the Wyresdale Tunnel, which crosses beneath the eastern part of this area, can be found in Johnson (1981) and Wilson et al. (1989). The area was first mapped at the 1:10 560 scale by J.R. Dakyns and R.H. Tiddeman in 1875-76 and published at the 1:10 560 scale in 1880 as parts of the Lancashire County Series sheets 30, 31, 34 and 35. In 1884 the geological information was published at the 1:63 360 scale as part of the Old Series sheet number 59 (Lancaster). During the present survey, the area to the south-east of the Quernrnore to Garstang road (approximately three quarters of the sheet) was mapped by Dr A.A. Wilson in 1984, as part of the BGS work commissioned by the North-west Water Authority in response to the Abbeystead Explosion Public Enquiry. Several, significant and previously unknown marine band localities were discovered by Dr Wilson during this survey. The remainder of the sheet was surveyed by Dr R.A. Hughes in 1988. A limited amount of field work was carried out by Dr A Brandon in 1990 and parts of the geological mapped revised. The area is one of hilly pastureland, marginal to the high, heather covered moorland of the Bowland Fells to the north-east. The rugged escarpment of Clougha extends into the north-east corner of the sheet, the highest point [5492 5939] being 421 m above Ordnance Datum. In the west, the north-east trending valley of the River Conder is the major topographical feature, and drains to the south. The lowest point is at the western end of the Conder valley [579 500], where elevation is less than 45 m above Ordnance Datum. To the east of the Conder valley the main lines of drainage flow from north to south along a series of glacial meltwater channels. The only centre of habitation is the ribbon development of Quernrnore [59 51]. The north-eastern part of the area was mapped by Moseley (1954). A detailed geological log of the Wyresdale Tunnel, constructed to link the drainage systems of the Rivers Lune and Wyre, was made by E.W. Johnson, N. Aitkenhead, J.I. Chisholm, R.S. Arthurton, and D.J.C. Mundy of the BGS, during construction. The results were published in a sedimentological synthesis by Johnson (1981), who described the succession in terms of a prograding delta-front sequence. Following the Wyresdale Tunnel explosion in May 1984, the BGS surveyed the area in an attempt to identify the source and the trap of the methane which exploded. A description of the geology as found during this survey is given in Wilson, Brandon, and Johnson (1989). All fossils recorded in this report were identified by Dr N.J.Riley. Subsequent to the preparation of the original draft report the stratigraphy and geological map of the area has been revised, particularly with regards to the Roeburndale Formation. This report therefore includes parts revised by Dr A Brandon in consultation with Or A A Wilson