LAUSR

Abstract The pre-Carboniferous evolution of the Eastern Tianshan orogen, Xinjiang, NW China, an important Paleozoic tectonic component and Cu metallogenic belt in the southern Central Asian Orogenic Belt (CAOB), is controversial. New zircon U Pb ages, whole-rock geochemistry, and zircon Lu Hf isotope data for three major granitic complexes (i.e., Kalatag, Dongerqu, Xierqu) from the Kalatag Cu cluster of Eastern Tianshan were combined with previous data to evaluate Ordovician–Devonian arc evolution and porphyry Cu fertility in the southern CAOB. The zircon U Pb results reveal that the granitic intrusions and porphyry Cu mineralization in the Kalatag area formed during 453–427 Ma and 387–379 Ma, suggesting that along with Carboniferous intrusions, Ordovician–Silurian and Devonian intrusions were also very important targets for porphyry Cu mineralization in Eastern Tianshan. All intrusions are calc-alkaline I-type rocks with low K2O/Na2O ratios (mostly  40, Yb