Altjawarra Craton Diamond Project Final Relinquishment Report for period ending May 23, 2004 for EL 22528 (Mount Ultim)

Abstract

Exploration License EL 22528 (Mount Ultim) is located on the Huckitta (SF53-11) 1:250,000 sheet in central Northern Territory. It is within the southern Georgina Basin. This report details all work carried out on the relinquished tenement up to May 23, 2004 by Elkedra Diamonds NL. Screening of the airborne magnetic data indicated that the tenement does not contain any large 'bulls-eye' anomalies likely to be due to large diatremes. Of the 31 photo feature anomalies identified from a detail photo interpretation study none were considered as priority targets representing potential volcanic pipes. However, stream sediment sampling confirmed previous reports that moderate-Cr chromites are present in the modern day drainages and mineral chemistry results suggests a mantle-derived source for these grains. Although indicator minerals and previous open file data suggests a source of the indicator minerals within the tenement area, the regional extent of Devonian contamination rocks with conglomerate horizons strongly indicates that there could be a secondary detrital source of the chromites with an original source possibly from Proterozoic basement rocks to the south. Isotope dating of detrital grains from two sedimentary rock samples supports, but does not prove, a southern provenance and potential secondary source. In light of the difficulties associated with tracing indicator mineral source origin within Devonian covered areas, coupled with logistical access difficulties, the tenement is ranked low priority in terms of diamond exploration within Elkedra's regional Altjawarra Craton project and no further work is currently warranted.