Genesis of ilmenite-series I-type granitoids at the Baogutu reduced porphyry Cu deposit, western Junggar, NW-China
Genesis of ilmenite-series I-type granitoids at the Baogutu reduced porphyry Cu deposit, western Junggar, NW-China
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西准噶尔包古图还原斑岩铜矿床钛铁矿系 I 型花岗岩的成因
DOI：
10.1016/j.lithos.2015.12.019
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发表时间：
2016-03
期刊：
影响因子：
3.5
通讯作者：
LuYing Jin
中科院分区：
文献类型：
--
作者：
MingJian Cao;KeZhang Qin;GuangMing Li;Noreen J. Evans;Pete Hollings;LuYing Jin
The Baogutu porphyry Cu deposit is a typical reduced porphyry Cu deposit, likely related to ilmenite-series I-type granitoids. However, the nature of the granitoids (ilmenite-series or magnetite-series) and the genesis of the Baogutu deposit are still under debate. In order to resolve these issues, whole-rock magnetic susceptibility, geochemistry and Sr–Nd–Pb isotopic, zircon U–Pb dating and Hf–O isotopic compositions were carried out. Three different intrusive phases are recognized within the deposit, from oldest to youngest, they are diorite with trace gabbro, diorite-granodiorite porphyry, and hornblende diorite porphyry, all of which were emplaced in the Late Carboniferous (320–306 Ma) and show a metaluminous, calc-alkaline I-type granitoid character with typical supra-subduction zone geochemical affinities. The intrusions are characterized by widespread primary pyrrhotite without anhydrite and hematite, dominant ilmenite over magnetite, low whole rock magnetic susceptibility (< 1 × 10− 4emu g− 1oe− 1or < 3 × 10− 3SI unit) and low whole rock Fe2O3/FeO ratios (< 0.4), indicating that the granitoids are ilmenite- rather than magnetite-series I-type granitoids. Whole rock Sr–Nd–Pb isotopic compositions show limited variation but slightly enriched characteristics with (87Sr/86Sr)ivalues of 0.70357–0.70404, εNd(t) of + 6.3 to + 7.8,206Pb/204Pb of 18.20–19.54 and208Pb/204Pb of 37.97–39.55. Zircon Hf–O isotopic compositions show εHf(t) values of + 10.7 to + 15.8 and δ18O of 5.3–7.4‰. Zircon and apatite saturation thermometries yield temperatures of 720 to 920 °C with relatively higher temperatures for the porphyries than for the diorite. Limited variations in Sr–Nd–Pb–Hf–O isotopic compositions and extremely young whole rock T2DM (Nd) (430 to 570 Ma) and zircon TDMC(Hf) (310 to 640 Ma) do not indicate significant crustal contamination during magma ascent or emplacement. Rather the Baogutu ilmenite-series I-type granitoids were probably formed by mixing between mantle-derived mafic magma and juvenile lower crust-derived felsic magma. Their relatively enriched characteristics and low oxidation state were probably inherited from magma sources (mantle wedge and juvenile lower crust) that had been previously contaminated with less than 8% of subducted oceanic sediments and reduced by CH4-bearing volatiles released from the asthenospheric mantle through a slab window.
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影响因子：
5.2
作者：
Keskin, M
通讯作者：
Keskin, M
影响因子：
1.8
作者：
T. Gold
通讯作者：
T. Gold
影响因子：
5.8
作者：
T. Takagi;K. Tsukimura
通讯作者：
T. Takagi;K. Tsukimura
DOI：
10.11456/shigenchishitsu1951.27.293
发表时间：
1977-10
期刊：
Mining geology
影响因子：
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作者：
S. Ishihara
通讯作者：
S. Ishihara
影响因子：
3.5
作者：
C. Smith;D. Canil;S. Rowins;R. Friedman
通讯作者：
C. Smith;D. Canil;S. Rowins;R. Friedman