断裂带中的方解石脉作为流体的直接记录,保存了丰富的断层活动信息。亚东裂谷是藏南地区南北向裂谷系中一条具有区域规模的大型裂谷,自北向南分别为热隆、涅如堆以及帕里次级裂谷。本文在涅如堆地堑南、北部和帕里地堑北部裂谷断层选取三个采样点,对沿断层发育的方解石脉进行研究,揭示了脉体与地震活动的关系、流体来源以及古地震发生时间。显微结构观察显示,方解石脉主要具有块状和拉长块状结构,分别代表了同震快速沉淀以及震后的同构造期沉淀。涅如堆地堑北部方解石脉具有Eu元素正异常以及高<sup>87</sup>Sr/<sup>86</sup>Sr比值的热液特征,异常轻的碳氧同位素值显示出地幔流体和大气水贡献。涅如堆地堑南部和帕里地堑北部方解石脉具有Ce和Eu负异常以及Y正异常的低温特征,与区域内灰岩相近的δ<sup>13</sup>C和<sup>87</sup>Sr/<sup>86</sup>Sr值反映了围岩来源,偏负的δ<sup>18</sup>O表明同样存在大气水贡献。方解石的地球化学特征反映了裂谷断层切割深度大,在断层活动期间能够沟通不同深度域的流体。断层亚东裂谷涅如堆段方解石脉铀系测年结果为距今679±129ka,帕里段北部结果为距今544±26ka、444±15ka和408±13ka,由于以上样品均具有同震或同构造期的内部结构特征,因此测年结果代表了地震活动时间。结合涅如堆段发育的断层三角面高差,计算出裂谷断层中更新世以来的E-W向伸展速率为0.17~0.24mm/yr,小于晚更新世以来0.8±0.3mm/yr的伸展速率,以及GPS观测的伸展速率6mm/yr。即中更新世以来,亚东裂谷涅如堆段断层活动速率逐渐增大。该地区断裂带中广泛发育的方解石脉能够为基岩区的断层活动和古地震研究提供宝贵的资料。;Calcite veins within fault zones, the direct records of fluids circulation, preserve a wealth of faulting activity information. The Yadong rift is a regional-scale structure in southern Tibet, part of the series of NS-trending South Tibetan rifts. From north to south, the Yadong rift is bounded to the east by the Relong, Nierudui, and Pagri normal faults. In this paper, we study the calcite veins from three sites along the Nierudui and Pagri faults in order to decipher their relationships with the seismicity, fluid source and paleoearthquake timing in this area. Microstructure observations show that calcite veins have blocky and elongated blocky textures, which can represent co-seismic rapid precipitation and post-seismic syntectonic precipitation, respectively. Calcite veins in the northern Nierudui graben show a positive Eu element anomaly and a high <sup>87</sup>Sr/<sup>86</sup>Sr value. The abnormally negative δ<sup>13</sup>C and δ<sup>18</sup>O values show the contribution of mantle fluid and meteoric water, respectively. Calcite veins in the southern Nierudui graben and northern Pagri graben show negative Ce and Eu, and positive Y, which may indicate a low-temperature tectonic setting. δ<sup>13</sup>C and <sup>87</sup>Sr/<sup>86</sup>Sr values similar to that of the regional limestone indicates the source of the host rock. The geochemical characteristics of the calcite veins may imply that the fault cuts deep across the crust, which facilitates fluids circulation at different depths during faulting activity. Results from uranium-series dating of calcite veins are 679±129ka in Nierudui, and 544±26ka, 444±15ka, and 408±13ka in the northern Pagri. Based on the vein microstructures, we suggest that the veins are coseismic or syntectonic structures, and as a result, U-Th dating results thus represent the timing of seismic activity. Combined with vertical offsets along the fault in Nierudui, we calculate an E-W extension rate of 0.17~0.24mm/yr since ~700ka, which is significantly smaller than the 0.8±0.3mm/yr since ~20ka, and the 6mm/yr observed by GPS. Therefore, we suggest that since the Middle Pelistocene, the rate of faulting activity along the Nierudui graben of the Yadong rift has gradually increased. The widespread calcite veins within the fault zones can provide valuable data for the study of faulting activity and paleoearthquakes timing in bedrock.