It was recognized that two magmatic belts in the Lhasa-Tengchong terrane formed due to the Mesozoic-Cenozoic Tethyan evolution. Still, their spatiotemporal variations of magmatic flare-ups/lulls are rarely discussed. Here we use the new U-Pb and Lu-Hf isotopic data of captured zircons and a comprehensive data set to show that the flare-up of northern magmatic belt has peak ages of 110 Ma in central and northern Lhasa and 120 Ma in eastern Tengchong, possibly related to the tectonic transition from Meso- and Neo-Tethyan double subduction to Neo-Tethyan single subduction. For the southern magmatic belt, the flare-ups at 100–85 Ma and 65–45 Ma in eastern southern Lhasa indicate obvious juvenile crustal growth, while flare-ups at 75–45 Ma in western southern Lhasa and Tengchong record ancient crustal reworking. Such flare-up variations in the southern magmatic belt possibly resulted from asynchronous changes in the Neo-Tethyan slab dip.

中文翻译：

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拉萨-腾冲地体白垩纪-始新世弧岩浆作用的时空变化

人们认识到，拉萨-腾冲地体中的两条岩浆带是由中生代-新生代特提斯演化而形成的。尽管如此，它们的岩浆爆发/平静的时空变化却很少被讨论。这里我们利用新捕获的锆石U-Pb和Lu-Hf同位素数据以及综合数据集表明，北部岩浆带爆发的峰值年龄为拉萨中北部110Ma，腾冲东部120Ma ，可能与中、新特提斯双俯冲向新特提斯单俯冲的构造转变有关。对于南部岩浆带，拉萨南部东部100~85Ma和65~45Ma的爆发表明了明显的新生地壳生长，而拉萨南部西部和腾冲75~45Ma的爆发记录了古代地壳的改造。南部岩浆带的这种爆发变化可能是由于新特提斯板块倾角的异步变化造成的。