U-Pb dating of detrital zircons from the pebbly siltstone at the top of the Tereeken Formation yielded the youngest zircon ages of 629±8 Ma, representing the maximum depositional age of the Tereekan glaciation. This result indicates that the Tereeken glaciation might be correlated with the Nantuo glaciation in the Yangtze Platform and the global Elatina or Marinoan glaciation. The remaining older zircons fall into three age-groups: 718-887 Ma, 1822-2092 Ma and 2345-2613 Ma, indicating three main Precambrian magmatic events in the Quruqtagh area.

In order to understand the Late Paleozoic tectonic setting of eastern part of Central Asian Orogenic Belt more deeply, the Permian volcanic rocks from Xi Ujimqin Banner, Inner Mongolia were selected to study their geochronology and geochemistry. The contents of major elements, the age, the contents of trace elements and REEs and the Sr-Nd isotopes of the volcanic rocks were measured by X-ray fluorescence spectrometry (XRF), SHRIMP zircon U-Pb, ICP-MS and ISOPROBE-T, respectively, and the results are as follows. The volcanic rocks consist of subordinate basaltic andesites and dominant rhyolites, with the SiO₂ content ranges of 53.54%?54.71% and 72.61%?80.81%, respectively. The SHRIMP zircon U-Pb age of one rhyolite specimen is about 279 ± 4.3 Ma, indicating that the rhyolites erupted in Early Permian. The basaltic andesites are characterized by slightly enriched LREE, depleted HREE, slightly negative Eu, Nb, Ta and Sr anomalies, and high abundances of LILE and HFSE, with the (La/Yb)_N ratios of 2.06 to 2.34. The mafic rocks may be inferred to generate from deep non-primitive mantle largely mixed by crustal source according to these features above. The rhyolites are characterized by slightly enriched LREE, depleted HREE, intensively negative Eu, Sr, P and Ti anomalies, slightly depleted Nb and Ta, and high abundances in K, Zr and Hf, with the (La/Yb)_N ratios ranging from 1.70 to 3.81, relatively high positive ε_Nd(t) values (+3.98?+5.62) and relatively young T_DM (490?690 Ma). The felsic rocks show an A-type affinity and may be inferred to come from a juvenile crustal source. According to their geochemistry, regional geology and previous studies, these bimodal volcanic rocks were generated by intra-plate volcanism and formed in a post-collisional extensional setting.