First and final report year ending 7 February 1991 Roper River area EL 7154

Abstract

3 aeromagnetic anomalies (RV3, RV9 and RV11) outlined from a survey flown in 1990 were followed up with a ground magnetic programme. 2 of these anomalies (RV3 and RV11) were considered worthy of further follow up on the basis of the ground magnetics. A short auger hole was drilled at RV3 to a total depth of 115.5m intersecting recent alluvium to 1.5m and weathered Velkerri Formation to total depth. RV11 was checked via a single bulk stream sediment sample and a singe RAB RC hole to 50m. This hole encountered soil, sand and gravel over weathered dolerite to 10m with fresh dolerite from 12m to 30m. A quartz veined breccia zone bearing sulphides was encountered at 39m continuing to total depth. This work failed to highlight any anomalous geochemistry or kimberlitic indicator minerals. 76 stream sediment and 21 rock chip samples were collected by Poseidon to follow up base metal anomalism determined by Stockdale. Several low order Pb (230ppm), Cu(80ppm), Bi(22ppm) and U(10ppm) anomalies were delineators but were not of sufficient coherency to warrant follow up.

Structural features reported include: Maiwok Sub basin.