Liang, Hua-YingCampbell, IanAllen, Charlotte MSun, WeidongLiu, Cong-QiangYu, Heng-XiangXie, Ying-WenZhang, Yu-Qiang2015-12-071432-1866http://hdl.handle.net/1885/19156Yulong ore-bearing porphyries, along the northwestern extension of the Red River-Ailao Shan fault system in eastern Tibet, consist of five porphyry deposits, containing a total of more than 8 million tons of copper resources. U-Th-Pb laser inductively coupled plasma mass spectrometry dating of zircon shows that the porphyries were emplaced in Early Tertiary (41.2-36.9 Ma), covering a period of ∼4.3 Ma, with formation ages decreasing systematically from northwest to southeast. The start of porphyry magmatism coincided with the onset of transpressional movement along the Red River-Ailao Shan fault system, implying a close link between these two events. Age sequence in intrusions can be plausibly explained by assuming that a region of melting in the lower northwestern plate moved southeasternward along the Tuoba-Mangkang fault relative to the upper plate. Zircon grains from the Yulong ore-bearing porphyries have higher Ce4+/Ce3+ than those from barren porphyries in the region. This suggests that the ore-bearing porphyries crystallized from a relatively oxidized magma, which has important implications for future ore exploration in the region and other Cu deposits in convergent margin environments in general.Keywords: fault zone; geochronology; inductively coupled plasma method; magmatism; melting; ore deposit; porphyry; subduction zone; tectonic setting; zircon; Ailao Mountains; Asia; China; Eurasia; Far East; North America; Red River [United States]; United States; X Continental subduction; Geochronology; Laser ablation ICP-MS; Porphyry copper deposits; Tibet; Zircon200610.1007/s00126-005-0047-12015-12-07