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Mineral exploration in the Lower Palaeozoic rocks of south-west Cumbria. Part 1, regional surveys

Cameron, D.G.; Cooper, D.C.; Johnson, E.W.; Roberts, P.D.; Cornwell, J.D.; Bland, D.J.; Nancarrow, P.H.A.. 1993 Mineral exploration in the Lower Palaeozoic rocks of south-west Cumbria. Part 1, regional surveys. Nottingham, UK, British Geological Survey, 90pp. (WF/93/004) (Unpublished)

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Abstract/Summary

The results of geochemical, geological and geophysical surveys over Lower Palaeozoic rocks in the south-western part of Cumbria are given in two reports. This report (Part 1) describes the results of a geochemical drainage survey and an examination of mineralised sites, and relates them to information from new geological mapping and an assessment of regional geophysical data. Part 2 contains details of follow-up surveys in the Black Combe inlier. The geochemical drainage survey, involving the collection and analysis of heavy mineral concentrates and stream sediment samples from 119 sites, found substantial antimony, arsenic, barium, bismuth, copper, iron, lead, tin, tungsten and zinc anomalies. Gold was reported for the first time from this part of the Lake District: small amounts were noted in panned concentrates from five sites. Other minerals identified in panned concentrates included arsenopyrite, baryte, bismutite, bismuthinite, cassiterite, chalcopyrite, cerussite, pyrite, pyromorphite, scheelite, sphalerite, stolzite and wolfram&e. The examination of old workings and outcrops revealed many undocumented occurrences of quartzsulphide vein-style mineralisation. The chemical analysis of samples taken from old workings and other occurrences confirmed field observations that locally, particularly in the Black Combe area, this mineralisation is polymetallic with variable amounts of arsenic, gold, bismuth, copper, lead, zinc and in a few cases antimony, barium, cobalt, nickel, tungsten and tin. Iron mineralisation occurs both as oxide (hematite) and sulphide deposits. Mercury was present in appreciable amounts in samples from the High Brow pyrite mine. The distribution of panned concentrate anomalies suggests that the vein-style mineralisation is polyphase and that individual phases may be zoned. Highest zinc anomalies occur near Torver and the highest lead on the west side of Black Combe. Tin and tungsten are restricted largely to the central part of Black Combe, and the most prominent arsenic and bismuth anomalies are found in the same area. Copper anomalies are widespread over the Skiddaw Group and the Borrowdale Volcanic Group. Barium anomalies indicate that baryte mineralisation is weak and localised, occurring principally within the Black Combe area and close to the Windermere Supergroup basal unconformity. Iron oxides from host rocks and hematite mineralisation are responsible for local enrichments of iron, antimony, arsenic and molybdenum in panned concentrates.

Item Type: Publication - Report (UNSPECIFIED)
Programmes: BGS Programmes > Economic Minerals
Funders/Sponsors: British Geological Survey
Additional Information. Not used in RCUK Gateway to Research.: This item has been internally reviewed but not externally peer-reviewed
Date made live: 03 Mar 2015 15:37 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/509953

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