Petrogenesis of Late Mesozoic mafic dykes in the Jiaodong Peninsula, eastern North China Craton and implications for the foundering of lower crust | |
Shen Liu; Ruizhong Hu; Shan Gao; Caixia Feng; Bobin Yu; Guangying Feng; Youqiang Qi; Tao Wang; Ian M. Coulson | |
2009 | |
发表期刊 | Lithos |
卷号 | 113期号:3-4页码:621-639 |
合作性质 | 其它 |
摘要 | Late Mesozoic (122.5–127 Ma) mafic dykes (dolerite-porphyries) in the Beibo gold district, Shandong Province, eastern North China Craton, can be subdivided into two groups (high-K and low-K) based upon K2O content. They are characterised by enrichment in light rare earth element (LREE) and some large ion lithophile elements (LILEs) (e.g., Rb, Ba and Sr), similar concentrations of heavy rare earth elements (HREEs),high (87Sr/86Sr)i ranging from 0.7094 to 0.7101, low εNd(t) values from −15.3 to −13.9, 206Pb/204Pb=16.98– 17.70, 207Pb/204Pb=15.47–15.55 and 208Pb/204Pb=37.61–37.89. In addition, the high-K dolerite-porphyries are distinguished by negative Eu, Nb, Ta, P anomalies in chondrite-normalised REE and primitive-mantle-normalised trace element diagrams. These features suggest that they were derived from a common, enriched garnetlherzolite mantle beneath the North China Craton, and that this was metasomatised by multiple enrichment events induced by hybridism of foundering lower crust at mantle depths. The low-K dolerite-porphyries were produced by 10–15% partial melting of the garnet-lherzolite source that had undergone metasomatism by carbonate-rich fluids producing secondary phlogopite and amphibole,whereas the high-K groupwas derived by relatively low-degree (3–5%) partial melting of a source that had experienced metasomatismby a carbonate-rich fluidwith crystallisation of only secondary amphibole. The Pd-subgroup platinum-group element (PPGE) (Rh, Pt and Pd) enrichment and Ir-subgroup platinum-group element (IPGE) (Ir and Ru) depletion of these mafic dykes suggest derivation from an S-unsaturated magma. Geochemical and PGE features indicate that fractionation of olivine, clinopyroxene, hornblende, plagioclase, ilmenite, titanite, apatite, laurite and Os–Ir–Ru alloys was important in the formation of the high-K maficmagma. Additionally, separation of all the above phaseswith the exception of plagioclase and apatite played an important role in the origin of low-K dolerite-porphyries. Minor crustal contamination also occurred during ascent of these mafic magmas. |
关键词 | Dolerite-porphyries Zircon U–pb Age Pge Petrogenesis Jiaodong North China Craton |
学科领域 | 矿床地球化学 |
收录类别 | SCI |
语种 | 英语 |
文献类型 | 期刊论文 |
条目标识符 | http://ir.gyig.ac.cn/handle/352002/3082 |
专题 | 矿床地球化学国家重点实验室_矿床地球化学国家重点实验室_期刊论文 矿床地球化学国家重点实验室 |
推荐引用方式 GB/T 7714 | Shen Liu,Ruizhong Hu,Shan Gao,et al. Petrogenesis of Late Mesozoic mafic dykes in the Jiaodong Peninsula, eastern North China Craton and implications for the foundering of lower crust[J]. Lithos,2009,113(3-4):621-639. |
APA | Shen Liu.,Ruizhong Hu.,Shan Gao.,Caixia Feng.,Bobin Yu.,...&Ian M. Coulson.(2009).Petrogenesis of Late Mesozoic mafic dykes in the Jiaodong Peninsula, eastern North China Craton and implications for the foundering of lower crust.Lithos,113(3-4),621-639. |
MLA | Shen Liu,et al."Petrogenesis of Late Mesozoic mafic dykes in the Jiaodong Peninsula, eastern North China Craton and implications for the foundering of lower crust".Lithos 113.3-4(2009):621-639. |
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