阿尔泰东南缘泥盆纪花岗质岩石的锆石U-Pb年龄、成因演化及构造意义:钙碱性-高钾钙碱性-碱性岩浆演化新证据
发布时间：2018-09-01 15:25
【摘要】：中国阿尔泰广泛发育的花岗质岩石已获得大量研究,但是其东南缘研究薄弱,制约了对整个阿尔泰造山带构造岩浆演化的认识。本文新获得阿尔泰东南缘四个花岗质岩体(昆格依特、库吉尔特、布铁乌及卡拉特玉别)锆石U-Pb年龄,分别为382±4Ma、381±4Ma、385±5Ma和363±6Ma。岩石学、地球化学特征等显示这些花岗质岩石具有高钾钙碱性、准铝质—弱过铝质的I型特点,全岩εNd(t)值为-2.42~-0.53,Nd模式年龄tDM为1.6~1.3Ga;锆石εHf(t)值为-3.44~+13.26,绝大多数为正值,锆石Hf二阶段模式年龄tDM-2为2.5~0.6Ga,表明源区物质组成复杂,有较多的新生幔源物质参与花岗质岩石的形成,并含有古老地壳成分。综合已有年龄分析显示,中国阿尔泰花岗质岩石的形成时代可分为480~440Ma(峰期460Ma)、420~390Ma(峰期400Ma)、390~370Ma(峰期380Ma)、370~360Ma(峰期365Ma)、360~350Ma。处于岩浆发育峰期的早泥盆世(420~390Ma)多为准铝-过铝质的钙碱性系列;中晚泥盆世(390~360Ma)多为准铝—弱过铝质的高钾钙碱性系列;370~360Ma为高钾钙碱性系列。该地区363Ma的高钾钙碱性花岗质岩石的确定,为进一步厘定整个阿尔泰泥盆纪花岗质岩浆由钙碱性(480~390Ma),到高钾钙碱性(390~360Ma),再到354Ma的布尔根碱性花岗岩的演变特点提供了新的证据,进一步揭示阿尔泰造山带该时期由俯冲增生演变到碰撞及后碰撞的演化过程。
[Abstract]:The extensive development of granitic rocks in Altai, China, has been extensively studied, but the study on the southeastern margin of the granitic rocks is weak, which restricts the understanding of tectonic magma evolution in the Altai orogenic belt. The zircon U-Pb ages of four granitic rocks (Kungoit, Kugill, Butiu and Karat jade) in the southeastern margin of Altai are 382 卤4 Ma, 381 卤4 Ma, 385 卤5Ma and 363 卤6 Ma, respectively. The petrological and geochemical characteristics of these granitic rocks indicate that these granitic rocks have the characteristics of high potassium calc-alkaline, quasi-aluminite-weak peraluminous type I. the whole rock 蔚 Nd (t) values are -2.42 ~ 0.53 ND model age tDM is 1.6 ~ 1.3Ga.The zircon 蔚 Hf (t) values are -3.44 ~ 13.26, mostly positive. The zircon Hf two-stage model age (tDM-2) is 2.5? 0. 6Ga, which indicates that the source region has a complex material composition, more new mantle source materials are involved in the formation of granitic rocks, and there are ancient crustal elements. The comprehensive age analysis shows that the age of formation of Altai granitic rocks in China can be divided into 480~440Ma (peak 460Ma) 420D 390Ma (peak-stage 400Ma) 370Ma (peak 380Ma) 370-360Ma (peak 365Ma) 360N350Ma.The age analysis shows that the age of Altai granitic rocks in China can be divided into 480~440Ma (peak 460Ma) 420D 390Ma (peak 400Ma) 370Ma (peak 380Ma). The early Devonian (420~390Ma) at the peak of magma development is mostly quasi-aluminum-peraluminous calc-alkaline series, and the 390~360Ma high-potassium calc-alkaline series of high-potassium calc-alkaline series at 370,360 Ma is a high-potassium calc-alkaline series. The determination of high-potassium calc-alkaline granitic rocks in 363Ma provides new evidence for the further determination of the evolution characteristics of the whole Altai Devonian granitic magma from calc-alkaline (480~390Ma) to high-potassium calc-alkaline (390~360Ma), and then to 354Ma's Burgen alkaline granite. It is further revealed that the Altai orogenic belt evolved from subduction to collision and post-collision in this period.
【作者单位】： 中国地质科学院地质研究所;中国地质大学(北京);新疆地矿局第八地质大队;
【基金】：NSFC-新疆联合基金重点支持项目(U1403291) 中国地质调查局项目(编号:12120113094000、1212010811033、12120113096500、1212010611803)联合资助
【分类号】：P597.3;P588.1
[Abstract]:The extensive development of granitic rocks in Altai, China, has been extensively studied, but the study on the southeastern margin of the granitic rocks is weak, which restricts the understanding of tectonic magma evolution in the Altai orogenic belt. The zircon U-Pb ages of four granitic rocks (Kungoit, Kugill, Butiu and Karat jade) in the southeastern margin of Altai are 382 卤4 Ma, 381 卤4 Ma, 385 卤5Ma and 363 卤6 Ma, respectively. The petrological and geochemical characteristics of these granitic rocks indicate that these granitic rocks have the characteristics of high potassium calc-alkaline, quasi-aluminite-weak peraluminous type I. the whole rock 蔚 Nd (t) values are -2.42 ~ 0.53 ND model age tDM is 1.6 ~ 1.3Ga.The zircon 蔚 Hf (t) values are -3.44 ~ 13.26, mostly positive. The zircon Hf two-stage model age (tDM-2) is 2.5? 0. 6Ga, which indicates that the source region has a complex material composition, more new mantle source materials are involved in the formation of granitic rocks, and there are ancient crustal elements. The comprehensive age analysis shows that the age of formation of Altai granitic rocks in China can be divided into 480~440Ma (peak 460Ma) 420D 390Ma (peak-stage 400Ma) 370Ma (peak 380Ma) 370-360Ma (peak 365Ma) 360N350Ma.The age analysis shows that the age of Altai granitic rocks in China can be divided into 480~440Ma (peak 460Ma) 420D 390Ma (peak 400Ma) 370Ma (peak 380Ma). The early Devonian (420~390Ma) at the peak of magma development is mostly quasi-aluminum-peraluminous calc-alkaline series, and the 390~360Ma high-potassium calc-alkaline series of high-potassium calc-alkaline series at 370,360 Ma is a high-potassium calc-alkaline series. The determination of high-potassium calc-alkaline granitic rocks in 363Ma provides new evidence for the further determination of the evolution characteristics of the whole Altai Devonian granitic magma from calc-alkaline (480~390Ma) to high-potassium calc-alkaline (390~360Ma), and then to 354Ma's Burgen alkaline granite. It is further revealed that the Altai orogenic belt evolved from subduction to collision and post-collision in this period.
【作者单位】： 中国地质科学院地质研究所;中国地质大学(北京);新疆地矿局第八地质大队;
【基金】：NSFC-新疆联合基金重点支持项目(U1403291) 中国地质调查局项目(编号:12120113094000、1212010811033、12120113096500、1212010611803)联合资助
【分类号】：P597.3;P588.1
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