The southern Jilin district is an important place in the northern margin of North China Craton (NCC),where the Archean is exposed.In order to study the tectono-magmatic thermal event of the NCC during Late Archean and the formation and evolution of the Early Precambrian continental crust,this study chose TTG gneisses of the Jiapigou complex as the research objective.The results show that the gneisses are characterized by high Al (Al2O3 =14.97％～16.28％) and high Na (Na2O=3.73％～4.54％),and poor Mg (MgO=1.96％～2.56％) with an average Mg index (Mg#) of 43;enrichment of LREE and depletion of HREE,without obvious Eu anomaly;enrichment of LILE {Sr(358 × 10-6～ 1114 × 10-6) and Ba (613×10-6～1200×10-6)},and depletion of HFSE {Nb(6.39× 10-6 ～11.2×10-6) and Ta (0.384× 10-6～0.679×10-6)},with low Yb (1.17×10-6～1.89×10-6) and Y (9.93×10-6～19.3×10-6) and very high Sr/Y ratio (36.0～57.7).These geochemical features show that the main residual phase contains garnet,amphibole and Ti-bearing minerals in the source,indicating that the gneiss should belong to the highpressure TTG series.LA-ICP-MS zircon U-Pb age data indicate that the rocks formed in the nearly 2509 Ma,suggesting that they were the result of the Late Archean.Combined with previous geochemical research of TTG gneiss and the data of Nd model ages,this period magma events may represent the remelting of older ancient crustal materials (～2.8 Ga).The study of petrography and zircon morphology shows that the area has experienced multiple metamorphism,among which the 2509 Ma high-degree metamorphism was coeval with magmatic event,likely related to underplating of mantle-derived magmas in the setting of mantle plumes.%吉林南部地区是华北克拉通北缘重要的太古宇出露区.为探讨华北克拉通新太古代构造-岩浆热事件的性质及早前寒武地壳的形成与演化,选择吉林南部夹皮沟TTG片麻杂岩进行研究.研究表明这套岩石高A1 (Al2O3=14.97％～16.28％),富Na(Na2O=3.73％～4.54％)、低Mg(MgO=1.96％～2.56％)且平均镁指数为43;富集LREE,亏损HREE,Eu异常并不明显;富集Sr(358×10-6～1114×10-6)、Ba(613×10-6～1200×10-6)等大离子亲石元素,亏损Nb(6.39×10-6～11.2×10-6)、Ta(0.384×10-6～0.679×10-6)等高场强元素;Yb (1.17×10-6～1.89×10-6)和Y(9.93×10-6～19.3×10-6)含量也很低,Sr/Y比值很高(36.0～57.7),以上地球化学特征表明其残留相主要为石榴子石、角闪石和含Ti矿物,没有斜长石,属于高压型TTG岩类.LA-ICP-MS锆石U-Pb结果表明其形成于～2509Ma,属于新太古代晚期的产物.结合以往TTG片麻岩类的地球化学研究及Nd模式年龄,这期岩浆事件可能代表古老地壳(～2.8Ga)的重熔.岩相学和锆石形态学研究表明研究区经历了多期变质作用,其中～2509Ma的高级变质事件与岩浆事件几乎同时,可能与地幔柱环境下的岩浆底侵作用有关.
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