塘坝金矿区位于西秦岭金矿带南成矿亚带的东段，金矿体主要分布于花岗斑岩上下盘附近的断裂构造中，或分布于花岗斑岩内部，花岗斑岩与金成矿关系密切。岩石地球化学分析结果显示：花岗斑岩具有高硅（w(SiO₂) 为70.84 %~75.23 %）、富铝（w(Al₂O₃) 为14.59 %~16.08 %）特征，A/CNK为1.05~1.32（均值为1.16），为硅和铝过饱和型，属于典型的过铝质花岗岩；稀土元素总量较低（30.72×10-6~97.81×10-6），轻稀土元素富集，重稀土元素亏损，轻、重稀土元素分馏明显（w(La)_N/w(Yb)_N为3.77~18.64），具有中等负铕异常（δEu为0.55~0.82，平均为0.67）；大离子亲石元素（Ba、Sr、Rb等）相对富集和高场强元素（Ta、Hf、Nb等）相对亏损。LA-ICP-MS锆石U-Pb测年结果显示，花岗斑岩成岩年龄为212.8 Ma±2.7 Ma，属于晚三叠世。花岗斑岩可能是以杂砂岩成分为主的沉积岩部分熔融形成花岗质岩浆在上升侵位过程中形成的，是一种典型的壳源成因类型。塘坝金矿区花岗斑岩具有后碰撞岩浆岩特征，是印支期华北板块与扬子板块碰撞导致地壳加厚，下地壳部分熔融的产物，形成于挤压环境向伸展环境转化阶段。

The Tangba Gold District is located in the eastern part of the southern mineralization sub-belt of the West Qinling gold ore belt.The gold ore bodies are mainly distributed in the fault structures near the hanging and foot walls of granite porphyry,or in the granite porphyry.The granite porphyry is closely related to gold mineralization.The geochemical analysis of the rock shows that the granite porphyry in the study area has high silicon (w(SiO₂) 70.84 %-75.23 %),rich aluminum (w(Al₂O₃) 14.59 %-16.08 %),A/CNK=1.05-1.32(mean value 1.16),which is supersaturated type silicon aluminum,belonging to typical peraluminous granite; the total amount of rare earth elements is low(30.72×10^-6-97.81×10^-6),LREE is enriched,HREE is depleted,and light and heavy rare earth fractionation is obvious(w(La)_N/w(Yb)_N=3.77-18.64),with moderate negative europium anomaly(δEu=0.55-0.82,average 0.67); trace element characteristics are characterized by large ion lithophile element enrichment and high field strength element relative loss.The zircon U-Pb dating results of LA-ICP-MS show that the diagenetic age of granite porphyry is 212.8 Ma±2.7 Ma,belonging to the Late Triassic.The rock mass may have formed during the ascending and emplacement process of the granitic magma formed by partial melting of sedimentary rocks dominated by the various sandstone components,and is a typical crustacean genetic type.The Tangba granite porphyry has the characteristics of post-collisional magmatism.It is the product of the partial melting of the crust under the thickening of the crust due to the collision of the North China plate and the Yangtze plate in Indosinian period.The granite porphyry formed in the transformation stage from the extrusion environment to the extension environment.