This paper presents abundances of major and trace elements of apatites in granitic rocks associated with different types of ore deposits in Central Kazakhstan on the basis of electron probe microanalysis and laser ablation inductively coupled plasma mass spectrometry. Our results demonstrate that the concentrations and ratios of elements in apatites from different granitoid rocks show distinct features, and are sensitive to magma evolution, petrogenetic and metallogenetic processes. Apatites in the rocks associated with Mo-W deposits have high content of F and MnO, low content of Cl, which may be indicative of sedimentary sources, while apatites from a Pb-Zn deposit show relatively high content of Cl and low F content, which possibly suggest a high water content. In these apatites, Sr contents decrease, while Mn and Y contents increase with magma evolution. This relationship reflects that these elements in apatites are related with the degree of magmatic differentiation. Four types of REE patterns in apatites are identified. Type 1 character of highest (La/Yb) N in apatites of Aktogai porphyry Cu-Mo deposit, Sayak-I skarn Cu deposit and Akzhal skarn Pb-Zn depposit is likely produced by the crystallization of heavy REE-enriched minerals. Type 2 character of upward-convex light REE in apatite of Aktogai porphyries likely results from La-enriched mineral crystallization. Type 3 feature of Nd depletion in apatites of East Kounrad and Zhanet deposits both from Mo-W deposits primarily inherits the character of host-rock. Type 4 apatites of Aktogai deposit and Akshatau W-Mo deposit with wide range of REE contents may suggest that apatites crystallize under a wide temperature range. Three types of apatite with distinct redox states are identified based on Eu anomaly. The Aktogai apatite with slight negative Eu anomaly displays the most oxidized state of the magma, and the apatites of other samples at Aktogai, East Kounrad and Akzhal with moderate negative Eu anomaly show moderate oxidizing condition of these rocks, while the remaining apatites with strong En anomaly indicate a moderate reductive state of these rocks.

The Central Asian Orogenic Belt (CAOB) hosts a number of porphyry Cu deposits, all associated with calcalkaline granitic rocks and ranging in size from giant to small. Major-and trace-element compositions of whole rocks and zircons grains were measured from 13 ore-bearing intrusions in nine porphyry Cu deposits (with 0.6 to 12 Mt Cu), including Bozshakol, Nurkazghan, Kounrad, Borly, Aktogai, and Koksai in Kazakhstan, Baogutu, and Tuwu-Yandong in China, and Erdenet in Mongolia. All zircon grains show high Ce 4+ /Ce 3+ ratios, ranging from 29 to 592. Higher Ce 4+ /Ce 3+ ratios are recorded at a given crystallization temperature from deposits with larger Cu tonnages. Large (>4 Mt Cu) and intermediate (1.5-4 Mt Cu) size porphyry Cu deposits are associated with granitic intrusions that have zircons with Ce 4+ /Ce 3+ ratios greater than 120. There is also a clear relationship between calculated log (fO 2) values and the size of deposits, with NNO + 2 values separating large and intermediate porphyry deposits from small deposits. The data of zircon Ce 4+ /Ce 3+ ratios and associated oxygen fugacity values in magma from ore-bearing intrusions indicate that more oxidized magmas are associated with the formation of larger porphyry Cu deposits. Such a conclusion may potentially be used in regional exploration for porphyry Cu deposits in the CAOB.

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The Central Asian metallogenic domain (CAMD) is a multi-core metallogenic system controlled by boundary strike-slip fault systems. The Balkhash metallogenic belt in Kazakhstan, in which occur many large and super-large porphyritic CueMo deposits and some quartz vein-and greisen-type WeMo deposits, is a well-known porphyritic CueMo metallogenic belt in the CAMD. In this paper 11 molybdenite samples from the western segment of the Balkhash metallogenic belt are selected for ReeOs compositional analyses and ReeOs isotopic dating. Molybdenites from the Borly porphyry Cu deposit and the three quartz vein-greisen WeMo depositsdEast Kounrad, Akshatau and Zhanetdall have relatively high Re contents (2712e2772 mg/g for Borly and 2.267e31.50 mg/g for the other three W eMo deposits), and lower common Os contents ( 0.670e2.696 ng/g for Borly and 0.0051e0.056 ng/g for the other three). The molybdenites from the Borly porphyry CueMo deposit Geoscience Frontiers journal homepage: www.elsevier.com/locate/gsf Geoscience Frontiers (2010) 1, 115e124 and the East Kounrad, Zhanet, and Akshatau quartz vein-and greisen-type WeMo deposits give average model ReeOs ages of 315.9 Ma, 298.0 Ma, 295.0 Ma, and 289.3 Ma respectively. Meanwhile, molybdenites from the East Kounrad, Zhanet, and Akshatau WeMo deposits give a ReeOs isochron age of 297.9 Ma, with an MSWD value of 0.97. ReeOs dating of the molybdenites indicates that CueWeMo metallogenesis in the western Balkhash metallogenic belt occurred during Late Carboniferous to Early Permian (315.9e289.3 Ma), while the porphyry CueMo deposits formed at w316 Ma, and the quartz vein-greisen WeMo deposits formed at w298 Ma. The ReeOs model and isochron ages thus suggest that Late Carboniferous porphyry granitoid and pegmatite magmatism took place during the late Hercynian movement. Compared to the Junggar-East Tianshan porphyry Cu metallogenic belt in northwestern China, the formation of the CueMo metallogenesis in the Balkhash metallogenic belt occurred between that of the Tuwu-Yandong in East Tianshan and the Baogutu porphyry Cu deposits in West Junggar. Collectively, the large-scale Late Carboniferous porphyry CueMo metallogenesis in the Central Asian metallogenic domain is related to Hercynian tectono-magmatic activities. ª

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