青海大柴旦塔温查干哈达顶志留世花岗岩岩石地球化学和U⁃Pb同位素约束  

Petrogeochemistry and U⁃Pb isotope constraint of the uppersilurian granites from the Da Qaidam Tawen Chagan Hada,Qinghai Province

作　　者：马国杰[1] MA Guojie(Geological Survey of Gansu Province,Lanzhou 730000,Gansu,China)

机构地区：[1]甘肃省地质调查院,甘肃兰州730000

出　　处：《资源信息与工程》2024年第3期10-13,共4页Resource Information and Engineering

摘　　要：青海大柴旦塔温查干哈达顶志留世花岗岩位于宗务隆山断裂以南,主体为花岗斑岩、粗粒似斑状二长花岗岩。岩石SiO_(2)质量分数为67.11%~73.73%,Al_(2)O_(3)质量分数为13.62%~14.57%,K_(2)O和Na_(2)O质量分数比为1.11~1.96,具有偏铝质高钾钙碱性系列岩石的特征。U⁃Pb年龄测试花岗斑岩的结晶年龄为(417.9±3.9)Ma,表明形成地质时期为顶志留世,属加里东期构造岩浆岩带。岩石地球化学分析认为,塔温查干哈达侵入岩属板内花岗岩类,可能为I⁃S型花岗岩,该期侵入岩属同碰撞构造前环境。岩浆活动总趋势由深到浅发展,随时间推移岩浆房逐渐趋近于地表。The Tawen Chagan Hada upper Silurian granite is located south of the Zongwulong mountain fault,which mainly consists of granite⁃porphyry and coarse⁃grained porphyritic monzonitic granite.It has the characteristics of semi⁃aluminous high potassium calc⁃alkaline series rocks,with SiO_(2)content ranging from 67.11%to 73.73%,Al_(2)O_(3)content ranging from 13.62%to 14.57%,and K_(2)O/Na_(2)O ratio ranging from 1.11 to 1.96.The U⁃Pb age test of the granite porphyry indicated a crystallization age of(417.9±3.9)Ma,suggesting that it was formed during the upper Silurian period and belongs to the Caledonian tectonic magmatic belt.According to the geochemical analysis,the Tawen Chagan Hada intrusive rocks belong to intraplate granites,possibly I⁃S type granites,and wereformedina pre⁃collisional tectonic environment.The general trend of magmatic activity develops from deep to shallow,and the magma chamber gradually approaches the surface as time goes by.

关 键 词：花岗岩 岩石地球化学 U⁃Pb测年 大柴旦 

分 类 号：P597[天文地球—地球化学]