This report describes the results of geochemical, geological and geophysical surveys across three
small areas of Carboniferous and Lower Palaeozoic rocks along the northern margin of the English
Lake District. The areas were chosen from the appraisal of regional-scale survey data described by
Cooper et al. (1991). In two of the areas, Ruthwaite and Tallentire, the objective was to provide
more information on the extent and magnitude of fracture-controlled epigenetic baryte and base
metal mineralisation. In the third area, at Whitrigg, brief surveys were carried out to aid the
interpretation of unexplained geochemical and geophysical anomalies found during two projects
carried out under the Mineral Exploration and Investment Grants Act (MEIGA).
At Ruthwaite, where a mine formerly worked baryte from a fault separating Lower Palaeozoic and
Carboniferous rocks, surface indications of further baryte mineralisation were found. Soil analyses
indicated that mineralisation may be present along the continuation of the faultline worked at
Ruthwaite and in the Eycott Volcanic Group rocks to the south of it. In this area relatively small,
but in some circumstances perhaps economically attractive, deposits of baryte may be present
under drift cover.
In the Tallentire Hill area, geological mapping followed by traverse-based soil sampling showed
that fracture-controlled mineralisation is widespread in the Carboniferous (Dinantian and
Namurian) rocks. The fracture fillings consist dominantly of baryte, often accompanied by
carbonate, with traces of copper and mercury. Where seen at surface the fracture fillings are too
small, patchy and low-grade to be of any economic importance. Baryte mineralisation also occurs
locally as patchy impregnations in sandstones. These are considered to be epigenetic deposits
related to the fracture-controlled mineralisation. Trial geophysical surveys suggested that electrical
methods may be useful in determining the extent of the mineralised sandstone. There is a
possibility that more extensive baryte deposits may be present in the limestone succession
underlying the mineralised sandstones.
In the Whitrigg area, Carboniferous rocks are separated from Lower Palaeozoic rocks of the
Eycott Volcanic Group by the easterly-trending Boundary Fault and north-westerly-trending
Bothel Fault. Evidence from an old mineral working and the results of a soil survey indicate that
patchy, epigenetic, fracture-controlled baryte and base metal mineralisation occurs along the
Bothel Fault and, locally, in the adjacent rocks. A feature of this mineralisation is the presence of
mercury, which is most abundant in a sample of brecciated and altered rock from the Eycott
Volcanic Group. Prominent base metal in soil anomalies discovered by MEIGA-funded projects
near Stangerhill are not associated with barium anomalies. It was concluded that these soil
anomalies are most likely to be caused by secondary concentration in overburden, and that the
source of metals may be a sub-cropping metalliferous horizon within the Carboniferous succession
or, more probably, fracture-controlled mineralisation.
Trial geophysical surveys carried out in all three areas indicated that in ground free of artificial
sources the VLF(EM) and conductivity mapping methods could be useful for tracing faults beneath
drift and providing information on drift thickness. Closely-spaced soil sampling proved effective for
detecting mineralisation in areas where the drift cover is thin, and a trial soil-gas survey showed
that this technique could also be useful for tracing faults beneath drift