华南陆壳基底的幕式生长——来自广东古寨花岗闪长岩中锆石LA-ICPMS定年的信息

The Episodic Growth of the Continental Crustal Basement in South China:Single Zircon LA-ICPMS U-Pb Dating of Guzhai Granodiorite in Guangdong

本文报道了粤东古寨岩体花岗闪长岩中锆石的多成因、多阶段LA-ICPMS U-Pb同位素年龄值。由此说明,华南陆壳基底可能具有多旋回幕式生长的特征。其生长幕较为精确的峰期时间(36个数据)依次为-3.1 Ga、2.7 Ga±、1.8 Ga±、1.6 Ga±、1.1 Ga±、0.91 Ga±、0.51 Ga±、0.20-0.10 Ga。同时表明,古寨岩体属于加里东早期,其成岩时间为507±17 Ma(MSWD=0.03)。此外,对比收集到的华南508个、澳大利亚1178个基底年龄数据,探讨了华南基底地壳形成和生长的几个相关问题。

Polygenetic zircons and multi-staged LA-ICPMS U-Pb ages of Guzhai granodiorite in the east of Guangdong Province are reported in this paper, which indicates that the South China continental crustal basement possibly has experienced polycyclical episodic growth. It is revealed that the peak ages of the zircon＇s crystallization （36 single zircons） are in turn as follows： -3. 1 Ga, 2.7 Ga±, 1.8 Ga±, 1.6 Ga±, 1.1 Ga±, 0. 91 Ga±, 0.51 Gaand 0.20-0. 10 Ga. It is also known that Guzhai granodiorite was emplaced in the early stage of the Caledonian, namely 507±17 Ma （MSWD= 0. 03）. Besides, based on dating data of the continental basement collected in South China （508 values） and Australia （1178 values）, several problems about the formation and growth of South China continental crust are discussed in this paper.