Miscellaneous investigations on mineralisation in sedimentary rocks

Five areas on the outcrop of the Helsby Sandstone
Formation (formerly Keuper Sandstone) and
Tarporle y Siltstone (formerly Waterstone)
(Warrington and others, 1980) coinciding with
known mineralisation were selected as targets for
a geochemical investigation. About 3750 soil
samples were collected and analysed for copper,
lead, cobalt and nickel. Geochemical maps are
presented to show the occurrence and distribution
of anomalous values.
In all the five areas investigated the geochemistry
of the soils identified the known areas
of mineralisation. In several instances other small
areas were also indicated where the soil values are
anomalously high and are presumed to reflect
local, hitherto unknown, mineralisation. None of
these areas, however, appear to have the area1
extent necessary for economic deposits.
The results of this preliminary investigation
indicate that in all cases the mineralisation is very
closely associated with permeable and porous
sandstone units which are faulted against less
permeable units forming trap structlzres for migrating
mineralising fluids.