Follow-up mineral reconnaissance investigations in the Northumberland trough

As a result of the data obtained from the Regional Mineral Reconnaissance of the Northumberland Trough, several areas were defined, largely on the basis of the total field magnetic data, for further investigation. Bateson and others (1983) have reported on the first phase of this work. The present report covers a further four areas. Soil geochemistry of each was examined in samples obtained from a regular grid together with ground magnetic measurements. In one area, Brown Moor, a programme of exploratory drilling (4 holes) was also undertaken. At Todridge Fell, Wheathill and Brown Moor the surface geochemical data indicate that faulting in the Whin Sill, is accompanied by mineralisation. The amount and type of such mineralisation is, however, not determinable except in the case of Brown Moor where the short drilling programme indicates alteration of the Whin accompanied by identifiable mineralisation particularly with respect to Mn, Ba and Pb. The work undertaken at Wesley resulted in the definition in soils of a linear zone enriched in Ba with associated higher than background values of Pb and En. A weak linear magnetic feature does not coincide with the surface geochemical "highs". The data cannot be used conclusively to determine the origin of these highs; mineralisation associated with a fault structure or a stratabound concentration are possible. As with the occurrences at Todridge and Wheathill, the source of the geochemical anomalies could only be determined by drilling. The work in these four areas, together with the &ta obtained at Newbrough (Bateson and others, 19831, indicates that in areas underlain by the Whin Sill magnetic methods can be used to identify fault structures affecting this basic body, with which alteration and mineralisation may be associated.