Stream sediment reconnaissance geochemical survey of the Amelia Dolomite, West of the Tawallah Fault, McArthur River District, NT

Abstract

Report outlines areas investigated using stream sediment and soil sampling for copper, lead and zinc. No conclusions drawn. Copper occurrences are known in the Amelia Dolomite west of the Tawallah Fault at the Kilgour copper mine (Walhallow 1:250,000 sheet area) at the Tawallah copper mine (Mount Young 1:250,000 sheet area). At Kilgour the mineralisation occurs as malachite joint fillings and along bedding planes in the Amelia Dolomite. This mineralization is thought to be stratigraphic. The surface width of the mineralized zone as indicated by a reconnaissance soil sampling traverse is 1000 feet (50 feet to 170 feet true width) but the strike length of mineralization his yet to be determined by further soil sampling and mapping. At the Tewallah Copper mine 56.25 feet of conformable mineralization occurs within the Amelia Dolomite host. (Marlow, 1963). Between these two copper shows occurs a discontinuous belt of Amelia Dolomite covering a surface area of approximately 260 square miles. Since the copper mimera1isation in these two mines was thought to be stratigraphic, the chances existed of other stratigraphic copper mineralisation elsewhere in the relatively unprospected Amelia Dolomite. The investigation was limited to the Amelia Dolomite, because stratiform copper mineralization is not known in the other formations west of the Tewallah Copper mineralisation is recorded in the Limmen Sandstone (Yah Yah copper prospect), Billengarrah Formation (Darcys) and the Tooganinie Formation (Johnston?s prospect). In all cases, however this mineralisation is fault controlled (i.e. in shears).