| 马兰峪背斜核部中生代侵入岩体锆石U-Pb年龄、地球化学特征及其构造意义 |
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| 关键词:Malanyu anticline LA-MC-ICP-MS zircon U-Pb age Petrogeochemistry Mesozoic |
| 基金项目:中国地质调查局项目“中国及邻区海陆大地构造研究”(编号: 12120113013700); “中国及邻区小比例尺地质图和大地构造图的编制”(编号: 12120113013800) |
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| Zircon U-Pb Ages and Geochemical Characteristics of the Mesozoic Intrusive Bodies along the Core of the Malanyu Anticline and Their Tectonic Significances |
| LA-MC-ICP-MS U-Pb dating of zircons from the Qianfenshuiling monzonitic granite, Maoshan monzonitic granite, Wangpingshi monzonitic granite, Gaojiadian quartz diorite, Xiaoyingzi granodiorite and moyite yielded (153.8±2.7) Ma, (162.7±1.5) Ma, (162.3±1.3) Ma, (170.5±1.8) Ma, (164.6±2.2) Ma and (186.8±1.3) Ma respectively, and several inheritable magmatic zircons were dated at 180~175 Ma and 201~186 Ma. The results indicate that the Mesozoic intrusive bodies along the core of the Malanyu anticlinorium were emplaced in the Indosinian and Yanshanian, with the latter being predominant. Their geochemical characteristics show that the magma was generated from partial melting of lower crustal material caused by the upper mantle underplating. Combining these data with the regional geological information, the authors have reached some conclusions: 1) the Malanyu anticline was initiated in the Indosinian period, and formed finally in the Yanshanian period; 2) the Indosinian-Yanshanian orogeny not only contributed to the crust thickening characterized by basement-involved folding but also resulted in partial melting of the lower crust, bringing about the fromation of intrusive bodies along the anticlinal core; and 3) the Mesozoic orogeny in the Yanshan area was represented not only by the tectonic process of the surface of the crust but also by the movement of the lower crust and upper mantle, which caused the northern part of the Sino-Korean block to enter into a new evolutionary stage, i.e., from the original stability to overall activation. |
| YANG Fu-ling,NIU Bao-gui,REN Ji-shun,LI Shan.2015.Zircon U-Pb Ages and Geochemical Characteristics of the Mesozoic Intrusive Bodies along the Core of the Malanyu Anticline and Their Tectonic Significances[J].Acta Geoscientica Sinica,36(4):455-465. |
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