Certain stratiform base metal sulphide deposits of the marine/marine-volcanic association are closely associated with ferruginous/siliceous sedimentary horizons (including banded iron formations). These chemical sedimentary horizons are known to occur in association with the Red Sea brine pool deposits, the Broken Hill deposits, the Kuroko deposits, and certain Canadian Shield deposits. The degree of association between these horizons and base metal mineralisation has hitherto been poorly researched, and the present work has attempted to demonstrate how such horizons which are closely associated with mineralisation on the Eyre Peninsula of South Australia differ from barren horizons, through orientation studies of geochemical/mineralogical/petrological characteristics that may be used as indicators to the proximity of mineralisation. 183 samples of ironstone and related material obtained from the study area were analysed for their trace element content. Approximately one-fifth of the samples are significantly anomalous in base metals, aside from Mn and Co - rich examples where heavy metal scavenging is likely to have occurred.