江山—绍兴断裂带构造格局的新元古代SHRIMP锆石U-Pb年龄证据

SHRIMP zircon U-Pb dating of the Jiangshan-Shaoxing faulted zone in Zhejiang and Jiangxi

报道采自双溪坞群不同岩组岩石样品的锆石年龄,其中,平水组英安质凝灰岩SHRIMP锆石U-Pb年龄为908.2±6.8Ma,双溪坞群北坞组安山岩年龄为901.6±5.5Ma,双溪坞群章村组火山角砾岩安山质角砾岩年龄为899±8Ma,上覆河上镇群骆家门组底砾岩(花岗闪长岩)SHRIMP锆石U-Pb年龄为878.96±4.5Ma。通过年龄数据探讨位于该断裂带的构造背景,依据该年龄数据限定区域地层对比和构造演化序列。锆石U-Pb年龄和地球化学标示了江山—绍兴断裂带北侧双溪坞群的沉积地层,地球化学分析表明该群代表了新元古代早期华南洋的中间岛弧。上述年龄为江山—绍兴断裂带变质地层的对比增添了可靠的年龄依据。

This paper reports SHRIMP zircon U-Pb ages （908~878Ma） of andisite and tuff of the Early Neoproterozoic Shuanxiwu Group on the northern side of the Jiangshan-Shaoxing faulted zone and discusses the tectonic background and regional stratigraphic correlation and tectonic evolution of the Jiangshan-Shaoxing faulted zone. The SHRIMP U-Pb ages and geochemical characteristics indicate the Early Neoproterozoic inner arc of the Shuanxiwu Group on the northern side of the Jiangshan-Shaoxing faulted zone. The SHRIMP U-Pb dating data obtained by the authors can provide new evidence for the correlation of metamorphosed strata in the Jiangshan-Shaoxing faulted zone.