U-Pb and Hf isotopic study of zircons of the Helanshan Complex: Constrains on the evolution of the Khondalite Belt in the Western Block of the North China Craton

► CL images reveal the coexistence of magmatic-type detrital zircons and metamorphic zircons in the high-grade pelitic granulites of the Helanshan Complex at the westernmost segment of the Khondalite Belt, North China Craton. ► LA-Q-ICP-MS U-Pb analyses on magmatic-type detrital zircons reveal two distinct age populations, one in the Archaean (2.85-2.53 Ga), the other in the Palaeoproterozoic (2.2-2.0 Ga). ► Hf isotopic data indicate two major crustal growth events, one in the Paleo-Mesoarchaean (3.3-3.1 Ga), another in the Palaeoproterozoic (2.4-2.0 Ga). ► Metamorphic zircons yield two groups of age, one at ~1.95 Ga and the other at ~1.87 Ga. ► The former is considered as the timing of the collision between the Yinshan and Ordos Blocks to form the Western Block, the latter is consistent with the age of ~1.86 Ga from two S-type granites, which are interpreted as the products of a post-orogenic event.