Precise U–Pb zircon–baddeleyite age of the Jinchuan sulfide ore-bearing ultramafic intrusion, western China

Zhang, Mingjie; Kamo, Sandra L.; Li, Chusi; Hu, Peiqing; Ripley, Edward M.

doi:10.1007/s00126-009-0259-x

Cited by 87 publications

(26 citation statements)

References 24 publications

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“…Available zircon U-Pb isotope ages indicate two episodes of mafic magmatism in the region. The older one took place at ∼830 Ma, as represented by the Jinchuan ultramafic intrusion Zhang et al 2010). The younger one occurred at ∼420 Ma, as represented by the Xijing mafic intrusion (Duan et al 2015a) and mafic dykes in the Jinchuan area (Duan et al 2015b).…”

Section: Geological Backgroundmentioning

confidence: 99%

Multiple S isotopes, zircon Hf isotopes, whole-rock Sr-Nd isotopes, and spatial variations of PGE tenors in the Jinchuan Ni-Cu-PGE deposit, NW China

Duan

Zhang

et al. 2015

Miner Deposita

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Previous geochemical data for the Jinchuan NiCu-(platinum-group elements, PGE) deposit, the single largest magmatic sulfide deposit in the world, are derived primarily from the upper parts of the deposit. This paper reports new PGE and S-Hf-Sr-Nd isotope data for the lower parts of the deposit that have become accessible for sampling by ongoing underground mining activity. New PGE data from this study, together with previous results, indicate that PGE tenors in the bulk sulfide ores of the deposit increase eastward, except for two fault-offset ore zones which occur together within the western part of the deposit. Generally, these two ore zones show depletions in IPGE (Ir, Ru, Rh) but not in PPGE (Pt, Pd) and Cu, and more fractionated olivine and Cr-spinel compositions than the rest of the deposit. These differences can be explained by a more evolved parental magma for the IPGEdepleted ore zones. The eastward increase of PGE tenors in the rest of the deposit can be explained by upgrading of preexisting sulfide liquid in a subhorizontal conduit by a new surge of magma moving through the conduit from west to east, which took place before the formation of the IPGEdepleted ore zones. The Jinchuan ultramafic rocks are characterized by elevated initial 87 Sr/ 86 Sr ratios from 0.7077 to 0.7093, negative ε Nd values from −9.2 to −10.5, and zircon ε Hf values from −4 to −7. These data indicate up to 20 % of crustal contamination in the Jinchuan magma. Four of nine multiple sulfur isotope analyses for the Jinchuan deposit show anomalous Δ 33 S values varying from 0.12 to 2.67‰. These results, together with elevated δ 34 S values (>2‰) for some of the samples analyzed previously by other researchers, indicate the involvement of external sulfur from Archean and Proterozoic sedimentary rocks. Modeling results based on our olivine data and magma compositions estimated previously by other researchers indicate that fractional crystallization did not play a major role in triggering sulfide saturation in the Jinchuan magma and that the parental magma experienced previous sulfide segregation during ascent or in staging chambers.

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Section: Geological Backgroundmentioning

confidence: 99%

Multiple S isotopes, zircon Hf isotopes, whole-rock Sr-Nd isotopes, and spatial variations of PGE tenors in the Jinchuan Ni-Cu-PGE deposit, NW China

Duan

Zhang

et al. 2015

Miner Deposita

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“…The main outcropping stratum of the area are the LS Group, the late Mesoproterozoic Dunzigou Group [29] and the Neoproterozoic-Cambrian Hanmushan Group [30,31]. As the basement rock, the LS Group is exposed in a long narrow belt about 500 km long and 30 km wide bounded by [38][39][40] • N latitude and 99-103 • E longitude in the LS area [32]. It is in unconformable contact with the overlying strata of the Dunzigou Group.…”

Section: Geological Settingmentioning

confidence: 99%

“…The ages of magmatic activities are from the Paleoproterozoic to Neopaleozoic and are concentrated in the Paleoproterozoic and the Paleozoic [19,20,26,27,[33][34][35][36]. The remarkable Jinchuan ore-bearing mafic to ultrabasic rocks formed at 800~850 Ma [37][38][39]. …”

Section: Geological Settingmentioning

confidence: 99%

Paleoproterozoic Multiple Tectonothermal Events in the Longshoushan Area, Western North China Craton and Their Geological Implication: Evidence from Geochemistry, Zircon U–Pb Geochronology and Hf Isotopes

et al. 2018

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Abstract:The Alxa block is located in the southwestern margin of the North China Craton. The Paleoproterozoic tectonic evolution, crustal growth and tectonic affinity of the block remain unknown or controversial. The Longshoushan (LS) area is one of the few areas that outcrop Paleoproterozoic to crystalline basement rocks in the Alxa Block. In this study, we preset whole-rock geochemistry, zircon U-Pb geochronology and Lu-Hf isotope data from metagabbro, metadiorite, quartz syenite, granitic leucosome and pegmatoid leucosome in the LS area. These rocks all are enriched in LREE and LILE, and depleted in HREE and HFSE. Eight new LA-ICP-MS zircon U-Pb ages yielded three magmatic ages of 2044 Ma, 2029 Ma and 1940 Ma, and three metamorphic ages of 1891 Ma, 1848 Ma and 1812 Ma. Lu-Hf analyses reveal that the magmatic zircons and anatectic/metamorphic zircons from all the rock types are characterized by positive εHf(t) (−0.16 to 10.89) and variable εHf(t) (−11.21 to 6.24), respectively. Based on the previous studies and our new data, we conclude that the LS area experienced three magmatic events (2.5-2.45 Ga, 2.1-2.0 Ga and~1.95-1.91 Ga) and three regional metamorphism/anataxis events (~1.93-1.89 Ga, 1.86-1.84 Ga and~1.81 Ga) in Paleoproterozoic. The age-Hf isotope data establishes two main crustal growth events at~2.9-2.5 Ga and~2.2-2.0 Ga in the LS area. These data indicate that the LS area experienced intraplate extensional setting in the middle Paleoproterozoic, and continental subduction, collision and exhumation in the late Paleoproterozoic. Combining the geochronological framework and tectonic evolution, we suggest that the Alxa Block is part of the Khondalite Belt.

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“…In the Jinchuan area (Fig. 2), the dolerite dykes intruded the ~830 Ma (zircon U-Pb age, Li et al, 2004;Zhang et al 2010) Jinchuan ultramafic intrusion (Fig. 3) which hosts the world's largest single magmatic sulfide deposit (Li and Ripley, 2011). Despite the cross-cutting relationship, the dolerite dykes and the Jinchuan ultramafic intrusion are thought to be coeval by some researchers (e.g., Li et al, 2005;, mainly because zircon crystals from a dyke sample analyzed by Li et al (2005) yield a U-Pb age of 828 ± 3 Ma.…”

Section: Introductionmentioning

confidence: 96%

Geochronological and geochemical constraints on the petrogenesis and tectonic significance of Paleozoic dolerite dykes in the southern margin of Alxa Block, North China Craton

Duan

Zhang

et al. 2015

Journal of Asian Earth Sciences

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Precise U–Pb zircon–baddeleyite age of the Jinchuan sulfide ore-bearing ultramafic intrusion, western China

Cited by 87 publications

References 24 publications

Multiple S isotopes, zircon Hf isotopes, whole-rock Sr-Nd isotopes, and spatial variations of PGE tenors in the Jinchuan Ni-Cu-PGE deposit, NW China

Multiple S isotopes, zircon Hf isotopes, whole-rock Sr-Nd isotopes, and spatial variations of PGE tenors in the Jinchuan Ni-Cu-PGE deposit, NW China

Paleoproterozoic Multiple Tectonothermal Events in the Longshoushan Area, Western North China Craton and Their Geological Implication: Evidence from Geochemistry, Zircon U–Pb Geochronology and Hf Isotopes

Geochronological and geochemical constraints on the petrogenesis and tectonic significance of Paleozoic dolerite dykes in the southern margin of Alxa Block, North China Craton

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