Abstract
The Jinjiang basic-intermediate dike swarms from southeast Fujian are further divided into two groups. The early-stage dike consist of hornblende diabases. They are distributed approximately along EW direction and are dated at 90 ± 2Ma by the zircon SHRIMP U-Pb method. The late-stage dikes, cutting the early-stage ones, are micro-diorite with NE-SW direction of distribution, and the zircon SHRIMP U-Pb age is 87 ± 2Ma. Two groups of dike intruded always along joints of the late Mesozoic granitic gneiss. Geochemically, they are calc-alkaline series of basalt to andesite compositions with MgO varying from 5.84% to 2.79%. These rocks are enriched in LREE, LILE and depleted in HFSE (especially Ta and Nb). The Jinjiang basic-intermediate dike rocks have limited ranges of Isr values from 0.7045 to 0.7053 and εNd (t) values from -1.18 to -1.97. The overall elemental and Sr-Nd isotopic characteristics of the Jinjiang basic-intermediate dike swarms are similar to those of mafic dikes from Chinmen and Liehyu islands, and are further consistent with those of the late Mesozoic basic igneous rocks (gabbros and basalts) in SE Fujian. It is proposed that the dike swarms were derived from differential basaltic magma produced from partial melting of sub-continental lithospheric mantle which could have been influenced by early subduction processes and formed in the continental extension setting.
Translated title of the contribution | SHRIMP U-Pb dating and lithogeochemistry of basic-intermediate dike swarms from Jinjiang, Fujian Province |
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Original language | Chinese |
Pages (from-to) | 1696-1702 |
Number of pages | 7 |
Journal | Acta Petrologica Sinica |
Volume | 22 |
Issue number | 6 |
Publication status | Published - 2006 |
Externally published | Yes |
Keywords
- Basic-intermediate dike swarms
- Jinjiang Fujian
- Late Mesozoic
- Lithogeochemistry
- SHRIMP U-Pb zircon dating