Progress report Tanami Magnetic Anomalies year ending 30-6-65.

Abstract

At the request of Messrs Fitzpatrick, Johnson and Associates, a magnetometer operator and magnetometer were supplied by McPhar Geophysics Pty Ltd, to carry out a location survey of two airborne anomaly areas in the Tanami-Granites area, Northern Territory. The operator was accompanied by an employee of Exoil and vehicles were supplied by the client company. The magnetometer employed was a McPhar M500A Flux-gate type unit. A second unit was carried as a spare. The general details of the survey are provided in the attached report by the magnetometer operator. There appear to be sufficient pegs used to locate the areas for further work. The results of the magnetometer survey are shown in individual profiles. The horizontal scale used is 1? = 4/l0ths of a mile; the vertical scale is 1? = 1000 gammas, and 1? = 500 gammas, as indicated on the profiles. The original profiles accompany this Memorandum. The location of the traverses are shown on two military maps; the Granites and Mount Solitaire, scale 1:250,000. The anomalies located on Traverse B1 Area ?A?, and Traverse B1, Area ?B?, are definitely associated with the airborne magnetic anomalies. There are apparently more outcrops than previously supposed and it may be possible to obtain a partial answer to the source of the anomalies by surface examinations in the immediate area of the anomalies. There should be no problem in locating the pegs if the work is carried out this year. There is little point in speculating as to the source of the anomalies until a detailed geological examination has been carried out. The following steps are strongly recommended before a comprehensive geophysical survey is considered iii either area. This work would consist primarily of a geological investigation of the ground magnetic anomalies. A magnetometer operator should accompany the geologist and several traverses, perpendicular to geologic strike, should be carried out in the vicinity of each anomaly for further evaluation, and to guide the location and direction of grid lines should the geology prove to be favourable. It is also recommended that soil, samples be collected on each traverse for geochemical analyses. This may require a third man but can be handled by the geologist and magnetometer operator if necessary. The above information should provide a realistic assessment of the areas, on which to base a decision for further work. The geologist, magnetometer operator, geochemical sampler team should really be employed on future initial location surveys to eliminate the need for return trips to the area, because of insufficient information. The anomaly at 4.2 miles west of the Granites should be examined with respect to the boundaries of the Peko lease, and. the known workings, and detailed measurements carried out if warranted. Geological and geochemical investigation of the minor anomalies on Traverse A1, east of Area ?A?, should also be carried out en route to the area.