Temporal evolution of the Permian large igneous province in Tarim Basin in northwestern China

Abstract

The temporal relations of different types of rocks in the Tarim large igneous province (TLIP) are studied using stratigraphic correlation, lithologically spatial distribution and isotopic ages. The TLIP covers an area >250,000 km 2 in the western and central part of the Tarim Basin. The lithological units of the TLIP include basalt, diabase, layered intrusive rock, breccia pipe mica-olivine pyroxenite, olivine pyroxenite, gabbro, ultramafic dyke, quartz syenite, quartz syenite porphyry and bimodal dyke. This is the first report for the spatial distribution of the TLIP from the spatial section lines, which shows the stratigraphic correlation among basaltic lava, tuff, interlayered mudstone, siltstone and sandstone and the thicknesses of the basaltic lavas from different field sections and drill holes, and the basalts from the Kupukuziman and Kaipaizileike Formations were subdivided in the drill hole sections. This indicates that the basaltic lavas were widely distributed in the Tarim Basin. Combined with previous study of geochemical and Sr–Nd–Pb isotopic characterization from the basalts and their genetic link with mantle plume activity, and large diabase swarms developments, the Permian igneous units constitute a Tarim large igneous province. Zircon SHRIMP U–Pb dating firstly yields 284.3 ± 2.8 Ma for the quartz syenite porphyry. Recent SHRIMP and LA-ICP-MS zircon U–Pb and 40Ar/ 39Ar ages are used to discuss temporal relations of different rock units in the TLIP formed between 290 and 274 Ma, and these data are more reliable than the K–Ar ages of 220–310 Ma reported previously. The sequence of magmatism of the TLIP in the central and western parts of the Tarim Basin are basaltic lava in the Kupukuziman and Kaipaizileike Formations (285–290 Ma), layered mafic–ultramafic rock, mica-olivine pyroxenite breccia pipe, diabase and ultramafic dyke, quartz syenite, quartz syenite porphyry and bimodal dyke (274–284 Ma).