KAT Exploration Inc (KATX)

[ShortonCash]

REE maybe a proximity indicator of IOCG...with other minerals found.

http://wiredspace.wits.ac.za/bitstream/handle/10539/1750/CHAPTER1___INTRO.pdf?sequence=2

The principal copper-bearing minerals are cogenetically-precipitated chalcopyrite, bornite and chalcocite (Plates 1.2 (a)-(c)) (Johnson & McCulloch, 1995) with minor native copper. Bornite and chalcocite often occur as exsolution intergrowths of each other (Plate 1.2 (d)-(e)). Minor gold and silver is intimately associated with the copper sulphides.

The central hematite-quartz breccia zone is noted as being essentially barren of copper-uranium mineralisation (Reynolds, 2000). The heterolithic microbreccia consists of fragments of hematite and altered granite in a matrix of quartz-hematite-sericite-siderite-chlorite (Pirajno, 2000).

However, a number of features are common to most descriptions of IOCG and related systems, and a number of other characteristics appear to be recurrent, although not necessarily universally present (Table 1.1).

Generally accepted distinguishing characteristics
• an abundance of Cu and Au
• extensive alkali-rich alteration of both sodic-calcic [Na(Ca)] and potassic [K] types (Hitzman et al. 1992; Barton & Johnson, 1996)
• voluminous low-Ti magnetite and/or hematite
• a distinctive suite of minor elements, i.e. REE, Co, Ag, + U, + P
• prominent structural control including localisation along high- to low-angle faults, generally splays off major crustal scale faults (Hitzman, 2000)
Potentially key characteristics
• adjunct coeval magmatism
• associations with distinctive magmas, e.g. high-K granitoids (Pollard, 2000) or alkaline magmatism (Meyer, 1988)
• non-magmatic brines, e.g. evaporitic fluids or basinal brines (Barton & Johnson, 1996; Haynes, 2000)
• distinctive tectonic environments, e.g. extensional or compressional settings (Hitzman, 2000)
• distinctive ages of formation, e.g. Mesoproterozoic (Meyer, 1988)

Copper-gold mineralisation (chalcopyrite + bornite) occurs within or near iron-oxide accumulations, of both hematite and magnetite character; where the hematite-dominated mineralisation is distal and shallow, and the magnetite-dominated mineralisation is deeper and earlier.

High-grade copper-uranium mineralisation generally correlates to more hematite altered rocks (Fe-metasomatised) and may be accompanied by fluorite, barite and REE phases. The exception is the central hematite-quartz breccia, which appears to be a final stage hydrothermal reworking of earlier generations of mineralisation. High-grade gold zones occur as narrow, complex zones around the silicified margins of the hematite-quartz core

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Fluorite mineralisation occurs together with sulphides in the mineralised breccias as disseminations, clasts and veins that may comprise up to 1-2 % of the rock. Barite characteristically occurs in the hematite-granite breccia and central hematite-quartz breccia core of the deposit, which contain lesser amounts of sulphide mineralisation

Figure 1.7. Generalised alteration and mineralisation patterns within the ODBC with some typical mineral assemblages. More common components of the ODBC shown in solid lines; neither absolute nor relative abundances are implied. mt=magnetite; hem=hematite; ser=sericite; chl=chlorite; sid=siderite; flu=fluorite; bar=barite; sil=silicification; py=pyrite; cp=chalcopyrite; bn=bornite; cc=chalcocite; Cuo=native copper; Auo=free gold; ura=uraninite; bra=brannerite; cof=coffinite; REE=lanthanum and cerium (from Reynolds, 2000).