【摘 要】
：
Widely distributed in Gyangz(e)-Chigu area, southern Tibet, NW- and nearly E-W-trending diabase(gabbro)-gabbro diorite dykes are regarded as the product of the
【机 构】
：
Institute of Mineral Resources
论文部分内容阅读
Widely distributed in Gyangz(e)-Chigu area, southern Tibet, NW- and nearly E-W-trending diabase(gabbro)-gabbro diorite dykes are regarded as the product of the large-scale spreading of the late Neo-Tethys Ocean. In order to constrain the emplacement age of these dykes, zircons of two samples from diabases in Nagarze were dated by using the U-Pb SHRIMP method. Two nearly the same weighted mean 206pb/238U ages were obtained in this paper, which are 134.9±1.8 Ma (MSWD=0.65) and 135.5 ± 2.1 Ma (MSWD=1.40), respectively. They not only represent the crystallization age of the diabase, but also documented an important spreading event of the Neo-Tethys Ocean during the late Jurassic and early Cretaceous. This dating result is of great significance to reconstruct the temporal framework of the late Neo-Tethys Ocean in the Qinghai-Tibet Plateau.
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