桂林理工大学学报2018，Vol.38Issue(4)：654-662,9.DOI:10.3969/j.issn.1674-9057.2018.04.006
海南岛晚二叠世大岭岩体岩石成因:锆石原位Hf同位素制约
Petrogenesis of the Late Permian Daling intrusion on Hainan Island: constraints from in-situ zircon Hf isotopes
摘要
Abstract
LA-ICP-MS zircon U - Pb geochronology shows that the Daling dioritic intrusion on northern Hainan Island,South China was emplaced at 255. 7 ± 1. 9 Ma. In-situ Hf isotopic compositions of zircon grains range from - 4. 7 to - 0. 2. Analytical results show that the εNd(256 Ma) value of the zircon grain with the lowest εHf(256 Ma) value is - 5. 6,which is consistent with those of the Daling intrusion(εNd(256 Ma) whole-rock = - 5. 8) and Meso - Neoproterozoic igneous rocks of the crystal basement on Hainan Island (εNd(256 Ma) whole-rock =- 7. 42 to - 4. 19) . However,εNd(256 Ma) values (- 4. 19 to - 2. 25) of high εHf(256 Ma) zircon grains are much higher than those of the Daling intrusion and Meso - Neoproterozoic igneous rocks,indicating a contribution to magmas from a relatively depleted(εHf(t) > 0) mantle source. Combined with major and trace-element compositions,Hf isotopic compositions of the analysed zircon grains suggest that the Daling dioritic intrusion cannot be formed directly by re-melting of Meso - Neoproterozoic igneous rocks on Hainan Island. Rather, the Daling intrusion was likely generated by the mixing of mafic magmas derived from a relatively juvenile, metasomatic lithospheric mantle source and felsic magmas produced by partial melting of the Meso - Neoproterozoic basement igneous rock. Therefore,the mixing of crust- and mantle-derived magmas can best explain geochemical characteristics of the Daling dioritic instrusion and variations of its zircon Hf isotopic compositions.关键词
二叠纪侵入岩/年代学/锆石Hf同位素/壳-幔岩浆混合作用/海南岛Key words
Permian intrusion/geochronology/zircon Hf isotope/crust-mantle magma mixing/Hainan Island!分类
天文与地球科学引用本文复制引用
温淑女,庞崇进..海南岛晚二叠世大岭岩体岩石成因:锆石原位Hf同位素制约[J].桂林理工大学学报,2018,38(4):654-662,9.基金项目
国家自然科学基金项目(41803020 （）
41703039) （）
广西自然科学基金项目(2015GXNSFBA139182) （2015GXNSFBA139182）
广西隐伏金属矿产勘查重点实验室项目(桂科隐16-140-27-01) （桂科隐16-140-27-01）
同位素地球化学国家重点实验室开放基金项目(SKLIG-KF-14-06) （SKLIG-KF-14-06）
