Final report on ELs 6286, 6294, 6295, 6300, 6301 and partial relinquishment report on ELs 6291, 6292, 6293, 6296, 6297, Roper River area, NT

Abstract

Possible kimberlitic indicators were identified from all of the licence areas sampled in 1989 and 1990. Microprobing of most of these grains showed them to be non kimberlitic or of low interest, but with scatter of kimberlitic grains being present. The better quality grains were followed up in the by heavy mineral stream and loam sampling, as well as limited rock sampling. This work failed to recover any further indicators. Aeromagnetic surveys were flown to include catchments and surrounding areas over which scattered kimberlitic indicators were recovered from reconnaissance sampling. Several anomalies were selected, which were in turn followed up by ground magnetic surveys, geological mapping, and check sampling. Given the intensity of the follow-up and the use of aeromagnetics over much of the follow-up area, it was decided that no further work was justified in the area of the relinquished areas. It is highly unlikely that a primary kimberlite is to be found in the relinquished area. The possibility remains that the undoubted kimberlitic grains were released from secondary sources of either Cambrian and/or Cretaceous age.