中文摘要：

本文研究浙西新路盆地中生代酸性火山岩的Sr—Nd同位素组成，探讨其源岩性质及其大地构造意义。结果显示，构成新路盆地主体的黄尖组晶屑熔结凝灰岩和花岗斑岩的Isr均值分别为0．71410和0．71039，ЁNd（t）值分别为-5．5和-5．7。黄尖组晶屑熔结凝灰岩和花岗斑岩的2阶段模式年龄（T2DM）均值分别为1366Ma和1387Ma，与扬子地块基底双溪坞群变质岩年龄（900～1000Ma）差异明显，而与华夏地块基底陈蔡群变质岩年龄（1400Ma）接近，2个单元火山岩Nd同位素均位于陈蔡群Nd同位素演化域。本研究认为，新路盆地黄尖组熔结凝灰岩和花岗斑岩具有相似的物质来源，均表现出壳源和幔源物质混合成因特点，壳源物质可能源自南部华夏地块的陈蔡群变质岩，与扬子地块变质基底双溪坞群无关，推测发生于900～1000Ma时期或其后的浙西地区扬子地块与华夏地块的陆-陆碰撞，具有华夏地块向扬子地块俯冲的动力学特点。上述大地构造运动方式以及岩石成因特点，或许是导致赣杭火山岩带分属华夏地块和扬子地块的火山岩均呈现出与铀成矿关系密切的重要原因。

英文摘要：

The Xinlu Basin located in southern margin of the Yangtze block, the north side of the middle Jiangshan-Shaoxing deep-fault, is a volcanic faulted-basin developed in Yanshanian epoch. Based on studying Sr-Nd isotopic composition of Mesozoic acid volcanic rocks from the Xinlu Basin, Western Zhejiang Province, source rock properties and dynamics of regional tectonic evolution were discussed in this paper. Results indicate that Isr mean values of crystal debris tuff from the Huangjian Formation and of granite-porphyry are 0. 714 10 and 0. 710 39, with εNd（t） mean value of -5.5 and -5.7, respectively. Two stage model ages（ T2DM ）of crystal debris tuff from the Huangjian Formation and of granite-porphyry are 1 366 Ma and 1 387 Chencai group in the basement of Cathaysia Block, Ma, respectively, close to the age （ 1 400 Ma） of and have remarkable difference with the age（ 900-1000 Ma） of Shuangxiwu group from the basement of Yangtze-block. The εNd（t） values both from the Huangjian Formation volcanic tuff and granite-porphyry are located in Nd isotopic evolutionary domain of Chencai group. It is also found that Huangjian Formation crystal debris tuff and granite-porphyry have similar source rocks related with mixing material derived from crust and lithospheric mantle. The part of the crust source may be from Chencai group metamorphic rock of the Cathaysia Block and has no connection with Shuangxiwu group within Yangtze block. It is speculated that continent-continentcollision had occurred during the period of 900 Ma to 1 000 Ma or later with dynamic characteristics of subduction flom the Cathaysia Block to the Yangtze Block in western Zhejiang Province.