The Borrowdale Volcanic Series of Coniston, Lancashire

Abstract

I. Introduction The Furness Fells lie at the extreme northern corner of Lancashire between the higher reaches of the River Duddon and the upper end of Lake Windermere. The highest summits are those of Wetherlam (2502 feet), Swirl How (2630 feet), Brim Fell (2611 feet), Old Man of Coniston (2633 feet), and Dow Crag (2555 feet). These are but the most prominent peaks on a high ridge extending from north-east to south-west. This watershed divides the waters which flow westwards to join the Duddon and northwards to the Brathay from those which find their way south-eastwards into Coniston Lake. From north to south there are six principal becks which, rising near the watershed, make their way ultimately to Coniston Lake. In the north Tilberthwaite Gill descends through its picturesque gorge along a course which is nearly northward in direction as far as Tilberthwaite, where, turning abruptly south-east and then south-west, it becomes known as Yewdale Beck, thereafter forming a strike stream almost along the junction between the Borrowdale Volcanic and later rocks. Approaching Coniston it again turns south-eastwards over the low ground to the lake. Church Beck is formed by the gathering together of a bunch of tributaries which are known as Red Dell Beck, Levers Water Beck, draining the tarn of that name, and Low Water Beck, which issues from Low Water. These all descend in marked steps to the Coniston Copper Mines, below which the main stream of Church Beck descends by a further succession of falls to

Controls of copper mineralization at Coniston, English Lake District

“…Mineral veins occur in all rock types, but as Mitchell (1940) pointed out, are most productive in the rhyolites. Mineral veins occur in all rock types, but as Mitchell (1940) pointed out, are most productive in the rhyolites.…”

“…In addition there are large numbers of small faults which are apparent on aerial photographs. Results for the whole area are shown on the composite diagram, which shows 3 main horizons (Mitchell, 1940) and again would probably have accompanied folding. The orientation of these faults is shown in Figure 2 for 6 sub-areas along strike from Coniston to Tilberthwaite.…”

“…Geology based onMitchell (1940). maxima, corresponding to the main trends of mineralized faults in Figure 2.…”

Pre-Acadian copper mineralization in the English Lake District

“…This wall-rock control of mineralization has long been recognized in the Coniston mines (e.g. Mitchell, 1940); typically, the veins are wide and productive within acid wall rock, but are characteristically poor or barren in andesite, andesitic tuff and volcaniclastic sandstone.…”

High‐level peperitic sills in the English Lake District: Distinction from block lavas, and implications for borrowdale volcanic group stratigraphy

“…An idpersistent and generally concordant andesite sheet, up to 15 m thick, can be traced for 2 km from Church Beck (SD 295 980) northwest across the Yewdale Fells to Low Wythow (SD 305 995, Figure 1). It occurs within subaqueously deposited fine-to coarse-grained bedded andesitic sediments which form part of Mitchell's (1940) 'Yewdale Tuffs'. Mitchell interpreted the sheet as a lava flow and noticed that it appeared to have burrowed down into underlying sediments.…”