The Changning-Menglian suture zone locating in the Sanjiang orogenic belt of SW China has widely been accepted as a vital remnant of the main Paleo-Tethys. Abundant magmatic rocks were induced by the oceanic subdution and closure. The most spectacular result was indicated by the gaint N-S trending Lincang granitic pluton exposed alongside the eastern margin of the suture, which provided us good oppotunity for understanding the tectonic evolution of the Paleo-Tethys. In this paper, the whole rock element geochemistry, zircon U-Pb chronology and Hf isotopic compositions were studied in the granites that were exposed in the Lincang area in the central part of Lincang rock basement. The zircon Pb-206/U-238 weighted average age of the experimental samples is 215. 5 +/- 0. 4Ma (MSWD = 2. 8, n = 23) , indicating that the magmatic rocks intruded in the Late Triassic. Granites belong to the high-K calc-alkaline series with lithology of granodiorite and monzogranite. The high aluminum saturation index (A/CNK =1. 09 similar to 1. 17) and the number of corundum molecules ( > 1% ) with aluminum feature. Samples were enriched in light rare earth elements (LREE/HREE = 6. 29 similar to 17. 01, (La/Yb) (N) = 6. 36 similar to 33. 5) , large ion lithophile and depleted Nb, Ta and other high field strength elements. The Hf isotopes of zircons are concentrated, the values of epsilon(Hf)( t) are negative ( - 15. 9 similar to - 9. 08) , Hf crustal age is older ( 1. 6 similar to 1. 9Ga) , the whole rock Zr saturation temperature (734 similar to 779 degrees C) indicated part of Lincang granite main crust base melting products, no significant mantle material added. S-type granite source area includes two types of meta-pelite and meta-greywacke, the study of Lincang granite source area is mainly meta-greywacke. Significant Eu negative anomalies (delta Eu = 0. 19 similar to 0. 58) and lower dissimilarity index (DI = 73 similar to 82) , indicating the presence of plagioclase and hornblende residues in the source area. The paper further summarizes and analyzes the geochemistry and isotope data of the predecessors. The results show that the genetic types of the granites in the Lincang rock basement are complex and changeable. From Late Permian to Late Triassic (260 similar to 200Ma) , the paleo-Tethys Ocean evolves successively from subduction to closure, and successively evolves various types of granites such as S-type, I-type and A-type. Based on the geological features of high-pressure metamorphic rocks and bimodal volcanic rocks parallel to the two sides of Lincang rock basement, it is considered that the main body of Lincang granite was formed in the syn-orogenic collision (250 similar to 237Ma) and post-orogenic collision (235 similar to 203Ma) , there were also a few magmatic rocks (similar to 252Ma) associated with subduction of oceanic basins in the early stage.
