Disko Bay Alluvial Diamond
The hard rock diamond programme in the Ataa Sund region is complemented by an alluvial diamond project in the Disko Nay region. Avannaa holds a 100% interest in license 2007/52 covering the regions of greatest alluvial diamond potential on eastern Disko and southern Nuussuaq. The licence area is 854 km2.
During 2008 Avannaa processed 150 tonnes of sediment from 9 samples sites in the licence area. The sediments were processed through an in-line pressure jig at a location on Disko island. The resultant concentrate was shipped to Copenhagen for further processing on an Armstrong grease table. The grease table extract is currently subject to analysis at SGS Lakefield.
Previous work by Charter Consolidated during the 1970’s reported findings of G9-G10 garnets in several recent drainage systems on the East coast of Disko Island. In 2005 GEUS initiated a program that retrieved additional G9 and G10 garnets and two micro diamonds from the Atane Formation sediments on Disko.
The geological setting of these finds is a Cretaceous-Tertiary braided river and floodplain system consisting of the erosion products from Archaean cratonic basement with a Palaeozoic cover sequence.The Atane Formation consists of poorly consolidated sandstones deposited in channels in a braided river system. Individual sand bodies deposited in river channels, can be traced for up to several kilometres along strike. The packages of channel facies sandstone are interleaved with silt and clay rich sediments, often including coal seams, which were deposited in flood plains. Sandstone and subordinate gravel make up some 82% of the approximately 400m nearly continuous stratigraphic section studied at Skansen, with the remainder being mudstone and coal of the floodplain deposits. The thickness of exposure of the Atane Formation in places exceeds 600m.
