Exploration for base metals - Southern margin of Bonaparte Gulf Basin.

Abstract

The Bonaparte Gulf Basin in the far NW corner of WA and transgressing into NT was becoming increasingly attractive for oil prospection over the last 10 years. Much work was done onshore where the smaller part of the basin could he studied. The bigger part lies to the north under the waters of the Joseph Bonaparte Gulf. Government as well as AAP geologists studied the area. We now have a very good knowledge of stratigraphy, structure and paleogeography of the basin. Particularly well known is the sequence upper devonian- lower carboniferous. The importance of this knowledge became dramatically apparent in the last few months when lead mineralization was discovered in the Sorby Hills during field work in mid 1971. AAP geologist, ELLOY, recognized galena in Buttons Bed dolomite close to a contact with Burt Range Formation sandstone. The author investigated the area in August, 1971 and discovered massive cerussite outcrops besides galena. This led to swift action by AAP and by now 4 mineral claims have been pegged, applied for and recommended by the Mining Warden in Wyndham for ministerial approval. Exploration work began in September, 1971. The author also made a literature study. In the following paragraph a brief description of the geology is given. When I realised the potential of the prospect during my first visit there in August, 1971, local surveyors were engaged and 3 mineral claims, each 300 acres (followed by a fourth one in 0ctober,1971), were pegged. They have by now been recommended by the Mining Warden for approval by the WA Minister of Mines. Messrs. BLANCY, BRGM Geologist, SYLVAIN (BRGM is equal partner with AAP in the venture) and myself visited the prospect again in September, 1971 and it was decided to, have SYLVAIN and one field assistant map the mineralized outcrop, take samples and make a preliminary assessment of the area. A local surveyor was engaged to peg a grid over the area, This grid is 250 m E-W and 650 m N-S with pegs every 50 M. SYLVAIN completed work in October and submitted a report plus geological map in November. Meanwhile samples have been sent to Pau, France for fossil determination. A study of the literature concerned with the Bonaparte Gulf Basin is continuing. A helicopter mission in the S of the Bonaparte Gulf Basin is planned for January, 1972 and during this time I will spent a few days in the Sorby Hills. It is intended to check on work previously done, to systematically collect rock samples, look for possible indications of structural and/or stratigraphical control of the mineralization and assess the potential of the eastern and southern Sorby Hills. If considered necessary, more claims will be pegged. Site for diamond drill holes will be determined.