The evidences are: 1) the presence of interstitial minerals rich in highly incompatible trace elements (mainly amphibole, phlogopite, ilmenite, apatite, zircon, baddeleyite
and titanite), 2) overgrowth of early crystallization phases towards a more differentiated composition (mainly plagioclase), and 3) disequilibrium between some interstitial crystals and previous minerals (e.g.
Inside, tiny crystals of the mineral baddeleyite
act like a geological clock.
is useful because it incorporates large amounts of uranium into its crystal-structure, and because uranium naturally decays to lead.
Current open pit production 1995 1996 Ore treated ('000 t) 29,551 29,153 Average grade (Cu %) 0.58 0.59 Copper concentrate produced ('000 t) 418.9 421.7 Ave concentrate grade (Cu %) 33.8 34.0 Copper in concentrate ('000 t) 141.7 143.4 Concentrate smelted on site ('000 t) 373.2 327.7 New copper anode output ('000 t) 113.4 105.2 Refined new copper output ('000 t) 115.8 104.3 By-products Magnetite concentrate ('000 t) 133 118 Uranium oxide (t) 133 100 Baddeleyite
('000 t) 15.5 13.2 Refined nickel sulphate (t) 177 215 N.B A major reverb furnace shutdown in 1996 and ongoing boiler problems resulted in lower production and lower concentrate smelted.
hematite and baddeleyite
, can also be helpful (Sabina, 1979; Cares, 1993).
A precise U-Pb zircon and baddeleyite
date gave 615 [+ or -] 2 Ma (Kamo et al.
Palabora, and neighbouring Foskor, are the world's primary producers of the zirconium ore Baddeleyite
, with Zr|O.sub.2~ + Hf|O.sub.2~ typically 99%, associated with the carbonatite deposit at Phalaborwa in northern Transvaal.
French, J.E., Heaman, L.M., and Chacko, T., 2002, Feasibility of chemical U-Th-total Pb baddeleyite
dating by electron microprobe: Chemical Geology, v.
and the niobium mineral pyrochlore are also present.
Species range from the very common (apophyllite, barite, calcite, corundum) to the semi-exotic (baddeleyite
, hauynite, nosean, ettringite, jeremejevite) to the extremely rare (hannebachite, willhendersonite, the not-yet-published batiferrite), and all in selections liberal enough to show a full range of habits--I counted 25 pictures, each one different, of barytolamprophyllite alone.
Similarly, Phalaborwa with its variety of economically exploitable copper, phosphate, vermiculite and co-products iron (magnetite), zirconium (baddeleyite
) and recovered by-products uranium, gold, silver, nickel, platinum and palladium, is a geological wonder".