| Abstract: | Abstract Widely distributed in Gyangzê‐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 Nagarzê 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. |
