陳正宏2006-07-252018-06-282006-07-252018-06-282005http://ntur.lib.ntu.edu.tw//handle/246246/11868Darongshan granitic suites are the most important and extensive Indosinian intrusive rocks in the Cathaysia Block. Many previous works, including field and dating studies, show that these granites were formed at the Hercynian-Indosinian periods. In order to better constrain the exactly intrusive ages and discuss their possible magma source, zircons from Darongshan granitic suites are separated for U-Pb age dating using the LA-ICP-MS method. We report the zircon U-Pb ages of granites from four batholiths of Darongshan granitic suites (Taima, Jiuzhou, Nadong and Pubai). Ages obtained are 255.3 ±2.9, 257.0 ±3.8, 259.7 ±3.1, 255.5 ±5.8 and 256.2 ±7.2 Ma, respectively, with the last two from the same batholith of Pubai. The data indicate that these granites are Indosinian intrusives emplaced at a very short period of time (260~255 Ma). However, all these samples inevitably contain many inherited zircons with ages ranging from Mesoprotero- zoic to Early Paleozoic (mostly Caledonian). Combined with the geochemical results we reported last year, it can be concluded that Darongshan granites were generated from remelting of the thickened (meta)sedimentary crust typical of the S-type granites.application/pdf176697 bytesapplication/pdfzh-TW國立臺灣大學地質科學系暨研究所reporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/11868/1/932116M002038.pdf