| 韩宇,侯荣俊,李长江,陈军典,吴爽,刘志学,常影,徐云霞,马双.黑龙江西北部早白垩世二长花岗岩锆石 U-Pb年龄及形成地质背景[J].矿产勘查,2025,16(6):1301-1310 |
| 黑龙江西北部早白垩世二长花岗岩锆石 U-Pb年龄及形成地质背景 |
| Zircon U-Pb age and the formation geological background of the Early Cretaceous monzonitic granite in northwestern Heilongjiang Province |
| 投稿时间：2024-05-10 |
| DOI：10.20008/j.kckc.202506001 |
| 中文关键词: 黑龙江西北部 二长花岗岩 锆石 U-Pb年龄 岩石成因 构造-岩浆演化 |
| 英文关键词: northwestern Heilongjiang monzonitic granite zircon U-Pb age petrogenesis tectonic-magmatic evolution |
| 基金项目:本文受中国地质调查局项目“黑龙江1∶5万1147高地(M51E004015)、工队(M51E004016)、1302高地(M51E005015)、1070高地(M51E005016)幅区域地质调查(1212011120659)”资助。 |
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| 中文摘要: |
| 黑龙江西北部位于中亚造山带东段，是蒙古—鄂霍茨克洋、古亚洲洋、环太平洋 3大构造域重叠部位，构造-岩浆活动强烈，对研究东北地区中生代构造-岩浆演化具有重要意义。本文以黑龙江西北部地区出露的白垩纪二长花岗岩岩体为研究对象，开展了系统的锆石 U-Pb同位素测年和岩石地球化学研究，讨论了其岩石成因及地质意义。锆石 U-Pb年代学研究结果显示，二长花岗岩成岩年龄为(144.67±0.48)Ma，成岩时代为早白垩世早期。岩石地球化学研究结果显示，二长花岗岩样品具有高硅、富碱、贫镁钙、高 FeOT/MgO比值，属准铝质、高钾-钙碱性系列，轻稀土元素(LREE)富集，重稀土(HREE)亏损，铕弱负异常，相对富集大离子亲石元素(LILE)Rb、Ba、Th、K，亏损高场强元素(HFSE)Nb、Ti、P，属于埃达克型(低 Sr低 Yb)花岗岩，是加厚陆壳被地幔玄武质岩浆底侵，使下地壳物质在高压、高温环境下，部分熔融的产物。结合年代学和地球化学特征，研究区二长花岗岩成岩构造背景受蒙古—鄂霍茨克洋构造域控制，形成于后碰撞构造背景。 |
| 英文摘要: |
| The northwestern Heilongjiang Province is located in the eastern part of the Central Asian OrogenicBelt. It is the overlapping part of the three major tectonic domains of Mongolia-Okhotsk Ocean, Paleo-Asian Oceanand circum-Pacific Ocean. The strong tectono-magmatic activity is of great significance to the study of Mesozoictectono-magmatic evolution in Northeast China. Zircon U-Pb isotope dating and geochemical studies were carriedout on the Cretaceous monzogranite rock mass in the northwest of Heilongjiang Province, discussing the petrogen.esis and geological significance. Zircon U-Pb dating results show that the monzonitic granites age is (144.67±0.48)Ma, falling in the Early Cretaceous period. The geochemical results showed that the granites are high in silica, alkaliand low in magnesium, calcium and the FeOT/MgO ratio, falling in the quasi-aluminous and high potash-calcium-alkaline series. The results also showed concentrated light rare earth elements (LREEs), deficient heavy rare earthelements (HREEs) and weakly negative europium, as well as concentrated large ionic lithophilic elements (LILEs)Rb, Ba, Th and K, and deficient high field strength elements (HFSEs) Nb, Ti and P, making them typical low Sr-YbAdak-types. It is the product of partial melting of the lower crustal material in a high-pressure and high-temperature environment caused by the underplating of the thickened continental crust by the mantle basalticmagma. Combined with chronology and geochemical characteristics, the diagenetic tectonic background of monzo.nitic granite is controlled by the Mongolia-Okhotsk Ocean tectonic domain and formed in the post-collision tec.tonic background. |
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