浙西北及江绍断裂带分别发现早古生代和 晚古生代岩浆活动

浙西北地区乃至浙赣皖相邻区早古生代受华南加里东构造活动的影响，仅发育轻微褶皱及断裂，造成上古生界与下伏前震旦系浅变质岩系—下古生界之间的区域性角度不整合，而不发育早古生代、晚古生代岩浆活动。在浙皖交界开化县获得445Ma±19Ma的岩浆岩LA-ICP-MS锆石U-Pb年龄，另在金华山后（江绍断裂带北侧）年龄为452.1Ma±2.7Ma的细粒花岗岩旁，发现了206Pb/238U年龄加权平均值为334.1Ma±2.4Ma的辉长闪长岩，暗示江绍断裂带在早古生代的构造活动可能引发了断裂带沿线及其北侧偏远处的岩浆活动，在晚古生代仍有较强的构造表现。由此可见，浙赣皖相邻区的加里东构造事件远比以往所认识的更强烈。这组年龄数据对重新认识浙赣皖相邻区和江绍断裂带的构造活动及其演化具有重要意义。

The discovery of the Early and Late Paleozoic magmatic activities in northwest Zhejiang Province, southeast China

It is generally considered that the Early Paleozoic geology of northwest Zhejiang and even the adjacent areas of Zhejiang such as Anhui, and Jiangxi Provinces(ZWG) is characterized by a series of folds, faults and the regional unconformity between the Late Paleozoic as well as the underlying Presinian epimetamorphic rocks and the lower part of the Early Paleozoic strata. These features resulted from the long-distance effect of the Caledonian tectonic event that occurred in South China. In contrast, Paleozoic magmatic activities in ZWG are generally to have been poorly developed. The authors obtained LA-ICP-MS zircon U-Pb weighted average ages of 445Ma±19Ma, 452.1Ma±2.7Ma, and 334.1Ma±2.4Ma for the magmatic rocks from the border area of Zhejiang and Anhui Provinces and the northern side of the Jiangshan-Shaoxing fault zone respectively, implying that only an intense tectonic activity once occurred in ZWG region during the Early Paleozoic, and there also existed a tectonomagmatic event along the fault zone during the Late Paleozoic. These data are valuable for the better understanding of tectonic evolution of Jiangshan-Shaoxing fault.