粤北黄岗镇侧塘早志留世具似大陆弧特征S型花岗岩成因及地质意义 |
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关键词:Cetang rock mass LA-ICP-MS zircon U-Pb dating Hf isotopic S-type granite |
基金项目:中国地质调查局地质调查项目(编号: DD20160032-17) |
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摘要: |
The Origin of the Early Silurian S-type Cetang Granite with the Continental Arc-like Feature from Huanggang Town in Northern Guangdong Province and Its Geological Significance |
The studied rock mass is located in the Wuyi–Yunkai orogenic belt, and its main rock is the gneissic granodioritic porphyry, indicating that the rock mass was formed in Early Silurian. The weighted average age of the zircon ages is (441.5±13) Ma. The K2O/Na2O ratios are higher than 1 (K2O/Na2O=1.10 ~ 4.50), with A/CNK ratios being 1.26~3.49, suggesting high potassium calc-alkaline strongly peraluminous series. The enrichment of Ba, Rb, Th and P, depletion of U, Pb, K, Sr and Ti, obvious enrichment of REE [(La/Yb)N=5.18~10.62], and obvious depletion of Eu (δEu =0.52~0.74) suggest the continental arc-like feature and indicate that the gneissic granodioritic porphyry in Cetang belongs to S type granite. The zircon Hf isotopic data indicate that the εHf(t) values are between –1.3 and –12.5, all less than 0, averaging –5.82. The zircon two-stage Hf model ages (TDM2) range from 1502 Ma to 2228 Ma (n=10), with their average age being 1 794.8 Ma. These characteristics indicate that the the gneissic middle-fine grained biotite adamellite is S type granite. The Cetang rock mass was formed as follows: The early intra-continent orogeny extrusion in the Wuyi–Yunkai orogen belt included fold and thrust nappe, which led to thickened crust and triggered partial melting of the Palaeoproterozoic–Mesoproterozoic sandy – greywacke granulite facies source from the lower crust. |
HUANG Kong-wen,GUO Min,TANG Ke,LIN Jie-chun,HU Qi-feng,WANG Qiu-chun.2021.The Origin of the Early Silurian S-type Cetang Granite with the Continental Arc-like Feature from Huanggang Town in Northern Guangdong Province and Its Geological Significance[J].Acta Geoscientica Sinica,42(4):487-500. |
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