地质通报
地質通報
지질통보
GEOLOGICAL BULLETIN OF CHINA
2014年
5期
595-605
,共11页
吴珍汉%叶培盛%吴中海%赵珍
吳珍漢%葉培盛%吳中海%趙珍
오진한%협배성%오중해%조진
雅拉香波穹隆%岩浆侵位%构造变形%LA-ICP-MS锆石U-Pb年龄%特提斯喜马拉雅构造带
雅拉香波穹隆%巖漿侵位%構造變形%LA-ICP-MS鋯石U-Pb年齡%特提斯喜馬拉雅構造帶
아랍향파궁륭%암장침위%구조변형%LA-ICP-MS고석U-Pb년령%특제사희마랍아구조대
Yalaxiangbo dome%magmatic emplacement%structural deformation%LA-ICP-MS zircon U-Pb ages%Tethys Himalayan belt
雅拉香波穹隆位于特提斯喜马拉雅构造带东部,出露显生宙不同时期的岩石地层,发育强烈韧性剪切变形和多期岩浆热事件,良好地记录了印度大陆俯冲导致的构造变形和岩浆热历史。对雅拉香波穹隆不同构造部位的花岗质岩石进行LA-ICP-MS锆石U-Pb同位素测年,获得4期构造岩浆事件的高精度测年数据。早期锆石年龄520.4±6.3Ma与536±12Ma指示喜马拉雅地块结晶基底泛非期岩浆侵位时代,晚期锆石年龄揭示新生代碰撞造山不同阶段构造热事件的发生时代。其中,45.6±1.2~44.16±0.88Ma反映印度大陆向北俯冲的起始时代,35.00±0.48Ma对应于始新世晚期增厚地壳深部构造热事件年龄,15.67±0.50Ma指示雅拉香波核部花岗岩侵位及穹隆的形成时代。
雅拉香波穹隆位于特提斯喜馬拉雅構造帶東部,齣露顯生宙不同時期的巖石地層,髮育彊烈韌性剪切變形和多期巖漿熱事件,良好地記錄瞭印度大陸俯遲導緻的構造變形和巖漿熱歷史。對雅拉香波穹隆不同構造部位的花崗質巖石進行LA-ICP-MS鋯石U-Pb同位素測年,穫得4期構造巖漿事件的高精度測年數據。早期鋯石年齡520.4±6.3Ma與536±12Ma指示喜馬拉雅地塊結晶基底汎非期巖漿侵位時代,晚期鋯石年齡揭示新生代踫撞造山不同階段構造熱事件的髮生時代。其中,45.6±1.2~44.16±0.88Ma反映印度大陸嚮北俯遲的起始時代,35.00±0.48Ma對應于始新世晚期增厚地殼深部構造熱事件年齡,15.67±0.50Ma指示雅拉香波覈部花崗巖侵位及穹隆的形成時代。
아랍향파궁륭위우특제사희마랍아구조대동부,출로현생주불동시기적암석지층,발육강렬인성전절변형화다기암장열사건,량호지기록료인도대륙부충도치적구조변형화암장열역사。대아랍향파궁륭불동구조부위적화강질암석진행LA-ICP-MS고석U-Pb동위소측년,획득4기구조암장사건적고정도측년수거。조기고석년령520.4±6.3Ma여536±12Ma지시희마랍아지괴결정기저범비기암장침위시대,만기고석년령게시신생대팽당조산불동계단구조열사건적발생시대。기중,45.6±1.2~44.16±0.88Ma반영인도대륙향북부충적기시시대,35.00±0.48Ma대응우시신세만기증후지각심부구조열사건년령,15.67±0.50Ma지시아랍향파핵부화강암침위급궁륭적형성시대。
Paleozoic-Cenozoic rocks and strata together with intense ductile shearing and magmatic thermal events occurred in the Yalaxiangbo (Yardoi) dome of eastern Tethys Himalayan belt, which well recorded the structural deformation and thermal history caused by northward subduction of the Indian Continental Plate. LA-ICP-MS U-Pb isotopic dating of zircons with clear growth zonation selected from granitic rocks sampled in different structural zones reveals high-resolution ages of four periods of tectonic-magmatic events that took place in the Yalaxiangbo dome. The U-Pb isotopic ages of zircons, 520.4 ± 6.3Ma and 536 ± 12.3Ma, are indicative of magmatic emplacement of the Pan-African orogeny in the crystalline basement of the Himalayan block. The other U-Pb isotopic ages of zircons reveal geological epochs of tectonic-thermal events during Cenozoic collisional orogeny, e.g., ages 45.6± 1.2~44.16±0.88Ma are indicative of the initial time of the northward subduction of the Indian Continental Plate, 35.00±0.48Ma is a representative age for Late Eocene tectonic-thermal event that occurred in the depth of the thickened crust, and 15.67±0.50Ma indi-cates the epoch of the emplacement of the core granite and the formation of the Yalaxiangbo dome.