The geology of the Barbon and Middleton Fells, near Kirkby Lonsdale, Westmorland

Furness, R. R. (Robert Rae), 1940

Abstract

The results of stratigraphical, palaeontological, petrographical, and sedimentological investigations into the Silurian strata of the Barbon and Middleton Fells, east of the Lune Valley Westmorland, are described,and compared with strata of a similar age in other parts of the country.

A detailed stratigraphical succession has been erected for the first time, the strata having been sub-divided on a lithological basis into the Coniston Grits and Bannisdale Slates. Zoning of this succession by means of the graptolite faunas reveals that the lundgreni, nilssoni-scanicus, leintwardinensis incipiens and leintwardinensis leintwardinensis zones are present in the area. The lundgreni fauna which is indicative of the upper part of the Wenlock Series, is restricted almost entirely to the southern extremity of the area. The remainder of the strata fall within the Ludlow Series.

Statistical investigations into the petrography of the coarse sediments have shown that they may be classified as fine grained greywackes, which have been derived from the northern part of the Southern Uplands. Consideration of sedimentary structures and changes in thickness and grain size of the sediments in adjacent areas supports this conclusion. This indicates that there is little evidence in favour of the Lake District and Southern Uplands areas of deposition being separated by a border land mass in Ludlovian times.

The coarse grained sediments are shown to have been brought into the area from the north-west, by comparatively vigorous turbidity currents. Finer grained sediments, however, are considered to represent deposition from low grade currents during quiescent periods which become more and more dominant in the higher parts of the succession. Pyritic films in these finer sediments suggest that deposition took place under anaerobic conditions.

Consideration of the structure has revealed that during the Caledonian orogeny the sediments were folded and faulted along WNW-ESE axes, to produce two large open synclines on which minor folding is superimposed. The effect of the later Hercynian orogeny was to introduce a set of N-S and NE-SW trending faults into the area, and to tilt the strata slightly to the north-west.

Citation

Furness, R. R. (. R. 1. The geology of the Barbon and Middleton Fells, near Kirkby Lonsdale, Westmorland. (Thesis). University of Hull. https://hull-repository.worktribe.com/output/4215903

• Thesis Type: Thesis
• Deposit Date: Jul 25, 2014
• Publicly Available Date: Feb 23, 2023
• Keywords: Geology
• Public URL: https://hull-repository.worktribe.com/output/4215903
• Additional Information: Department of Geology, The University of Hull
• Award Date: Aug 1, 1965