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

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

Vanadiferous nodules from the Littleham Marl near Budleigh Salterton, Devon

A collection of nodules from the Littleh~ Marl sequence near Budleigh Salterton was submitted for investigation of their composition and mineralogy (13 specimens, table A). Initially, three were selected for sectioning and analysis, but preliminary results revealed such wide variations in composition and mineralogy that a qualitative study of the collection was followed by fuller analyses of some examples which showed significant concentrations of elements of interest such as U, V, Cu, Co and Ag. Techniques used included XRF, electron microprobe, XRD, and evolved gas analysis. In this . instance, microprobe analysis was confined to point analyses of selected mineral grains due to the restricted time available. Detailed multi-element line scans or area imaging using the microprobe would have been inordinately time consuming for the comparatively large surface areas of these specimens. Further work on this aspect might be carried out using SEM techniques

The sand and gravel resources of the country around Chichester and north of Bognor Regis, Sussex : description of 1:25,000 sheet SU 80 and 90

The geological maps of the Institute of Geological Sciences, pre-existing borehole information and 138 boreholes drilled for the Industrial Minerals Assessment Unit (IMAU) form the basis for the assessment of the sand and gravel resources of the country around Chichester and north of Bognor Regis, Sussex. All the deposits in the district that might be potentially workable for sand and gravel have been investigated and a simple statistical method has been used to estimate the volume. The reliability of the volume estimates is given at the symmetrical 95 per cent probability level. The mineral bearing ground is divided into eight resource blocks, containing between 7.5 and 16.1 km2 of potentially workable sand and gravel. For each block the geology of the deposits is described, and the mineral bearing area, the mean thicknesses of overburden and mineral and the mean gradings of the mineral are stated; detailed borehole data are also given. The geology, the positions of the boreholes and the outlines of the resource blocks are shown on the accompanying resource map