Zircon U-Pb dating and geochemical of basalts in Qipan Country of Northwest Tarim Basin

The age of basalts in the Youlebasi of Qipan Country in the Southwest of Tarim Basin by zircon LA-ICP-MS U-Pb dating is 298.3 plus or minus 2.8 Ma(MSWD=2.6), which represents the crystallization age of the volcanic rocks erupted in Early Permian. The basalts have the characteristics of high Ti(Ti/Y=513.86~577.35), high Nb(28x10(-6)~35.7x10(-6)) and low Zr/Nb ratios(10~10.86), which indicates that the basalts were derivate from enrich mantle sources. While the slightly low Nb/U(~30)and Ce/Pb(~15)indicated that the basalts derivate from the continental lithosphere or subjected to some degree of crustal contamination. The Youlebasi basalts have higher TiO(2) and P(2)O(5) contents, enrich LREE, Rb and Ba, which indicates that basalts have geochemical characteristic of mantle plume. Based on large-scale volcanic eruption Tarim area and the characteristics of enrichment incompatible elements and facies paleogeography, the basalts in the Southwe