Marcollat. Progress, annual and final reports to licence expiry/full surrender for the period 23/9/2002 to 9/10/2008.
Published: 24 Nov 1908 Created: 12 Nov 2024 Revised: 12 Nov 2024

Exploration of an area located 50 km south-southwest of Keith aimed to test the potential of known Cambrian siliceous volcanic rocks for hosting massive base metal sulphide deposits plus possible disseminated and skarn-related precious metals,...

Exploration of an area located 50 km south-southwest of Keith aimed to test the potential of known Cambrian siliceous volcanic rocks for hosting massive base metal sulphide deposits plus possible disseminated and skarn-related precious metals, following an exploration model put forward on the basis of the rocks' supposed petrological and geochemical similarities with the Mount Read Volcanics of western Tasmania. Early work consisted of an interpretation of regional magnetic data, scout geological mapping and geochemical grab sampling of sparse basement outcrops, and the acquisition and interpretation of ground magnetic, gravity and TEM surveys intended to firm up drillable targets. No useful TEM results were obtained. The north-south volcanic belt crossing the licence area was interpreted to be demagnetised over a strike length of about 25 km. Within it the licensee discerned three small linear magnetic highs 1-2 km long with maximum amplitudes of 400 nT. These appeared to be conformable with the volcanic strata, and it was inferred that they might arise from pyrrhotite-bearing skarn or from massive sulphide deposits. Difficulties ensued with securing a drilling contractor and with finding a joint venture partner to help bear the cost of drill testing the chosen magnetic anomalies. Consequently, no work took place during the period July 2004 until June 2007. On 30/5/2007 an option agreement was signed by the licensee with Uranium Exploration Australia, who undertook to fund drilling activities over two years in order to earn a 50% interest in the tenement. However, the agreement was allowed by that company to lapse on 13/2/2008 without its requirements being fully exercised. The main field activity carried out under EL 3013 was the completion of a single vertical rotary mud - HQ/NQ diamond drillhole 336.1 m deep at the Clover Ridge magnetic/gravity anomaly during the week of 5-11/6/2007. After passing through 53.8 m thickness of Cenozoic cover rocks, the hole stayed within a tholeiitic dolerite intrusion for the remainder of its length. The mafic rocks recovered in the drill core show chlorite, epidote and carbonate alteration and veining plus the effects of contact metamorphism, but their sulphide content is minor and the core sample assay results were not encouraging. Petrographic work suggested that the magnetite which produces the Clover Ridge magnetic anomaly predates contact metamorphism, and is therefore not related to skarn mineralisation. Hence, if the magnetite in the dolerite is not related to contact metamorphism, it is likely that the dyke post-dates regional hydrothermal alteration which destroyed magnetite, an observation based on the airborne magnetic data. Any volcanogenic massive sulphide (VMS) deposits in the area would then be contemporaneous with the regional alteration, and thus pre-date the dyke. It was concluded, therefore, that drillhole 07CR001 had done little to elucidate the potential of EL 3013 for VMS mineralisation. Given the presence of magnetic dykes in the area, it now seemed to the licensee that ongoing use of magnetic data as the primary exploration tool would not be reliable. Electrical geophysics might also struggle, as any zinc-rich ores would be poor conductors. But better results might be achieved using gravity, given that VMS deposits have very high specific gravities. It was suggested that any future gravity survey should concentrate on the 20 km long demagnetised zone in the southern half of the licence area, since this demagnetisation may have been caused by sulphur-rich fluids which had converted magnetite to pyrite (and in this process may also have deposited valuable metals).

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About this record

Record No mesac22221
Topic Geoscientific Information
Type of Resource Document
Category Type
Document Type Mineral Company Report - Mineral Exploration
Contributor
Sponsor Rosscraft Minerals Pty Ltd
Tenement
Tenement Holder Rosscraft Minerals Pty Ltd;Uranium Exploration Australia Ltd
Operator Rosscraft Minerals Pty Ltd
Geological Province
Mine Name Clover Ridge magnetic anomaly;Willalooka magnetic anomaly;Kyeema magnetic anomaly
Stratigraphy
Commodity
Notes
Notes: Includes:   - Rossiter, A.G. and White, A.J.R., November 2003. The case for the continuation of the Mount Read Volcanics into south-eastern South Australia. Research paper submitted by Rosscraft Minerals as the first annual report for EL...

Notes: Includes: - Rossiter, A.G. and White, A.J.R., November 2003. The case for the continuation of the Mount Read Volcanics into south-eastern South Australia. Research paper submitted by Rosscraft Minerals as the first annual report for EL 3013. 21 pages, 1 appx, 12 fig, 14 ref, 5 tables. Geographic Locality: Upper South-East;Marcollat;Peacock Range;JipJip Rocks;Glenstrae Farm Doc No: Env 10122 Drillhole: DDH 07CR001 Drillhole Unit No: 6924 03955

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Language English
Metadata Standard ISO 19115-3

Citations

Use constraints License
License Creative Commons Attribution 4.0
Persistent identifier https://pid.sarig.sa.gov.au/document/mesac22221
Citation Rossiter, A.G.;White, A.J.R.;England, R.N. 1908. Marcollat. Progress, annual and final reports to licence expiry/full surrender for the period 23/9/2002 to 9/10/2008. Mineral Company Report - Mineral Exploration
https://pid.sarig.sa.gov.au/document/mesac22221

Technical information

Status
Maintenance and Update Frequency
Geographic Reference GDA2020 (EPSG:7844)
Geo bounding box {"type":"Polygon","coordinates":[[[140,-37],[140.5,-37],[140.5,-36],[140,-36],[140,-37]]]}
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Lineage