1971 Report on reconnaissance trip to AP 2694 Victoria River Basin.

Abstract

During the authors' recent visit, Areas 1, 4, 5 and 6, were briefly examined. A limited number of stream sediment samples were collected for assay to indicate the general level of metal values to be expected within the area. Experience has shown that for regional geochemical work, the minus 80 mesh fraction of stream sediment is generally suitable for exploration assays. No difficulty was found in the field in collecting samples with sufficient minus 80 mesh material for assay. Twenty samples were collected, sieved at minus 80 mesh, and the fine fraction analysed by geochemical, atomic absorption techniques for copper, cobalt, nickel, manganese, zinc, lead, silver and arsenic.

These results suggest that there is little significant variation in background values in sediments derived from streams draining the various lithological units. This should considerably simplify the interpretation of analytical data derived from a full geochemical exploration programme. Although present data is somewhat inadequate, it would appear that the mean background values for some of the metals will be approximately as follows: Nickel 10 ppm, Copper 15 ppm, Zinc 20 ppm, Lead 20 ppm, Cobalt 10 ppm. Silver and arsenic values would appear to be uniformly low while insufficient manganese values are available, in view of the wide range of results (60 ppm to 700 ppm), to allow meaningful comment at this time. a) The reconnaissance visit has broadly confirmed the structure and stratigraphy of the area as outlined in our previous reports. b) The various possibilities of mineralisation as outlined in our previous reports continue to be valid. c) The analytical data suggests that background metal values for each of a number of elements in stream sediments derived from the various lithological units are comparable.