The latest Devonian-early Carboniferous granitic intrusions in the Central Tianshan block are composed mainly of monzogranites and granodiorites. Here we present the petrology, geochemistry, and in situ zircon U-Pb ages and Hf isotopes of these intrusions. Bulk geochemistry suggests that the monzogranites and granodiorites are high-K, calc-alkaline, I-type granites. LA-ICP-MS zircon dating shows that the monzogranites and granodiorites formed at ca. 362 Ma and ca. 354 Ma, respectively. They are characterized by relatively high initial Hf-176/Hf-177 ratios (0.282571-0.282764) and positive epsilon(Hf(t)) values (+2.1 to +7.2). We interpret them to have been derived from partial melting of the Mesoproterozoic metamorphic basement of the Tianshan block and a significant addition of juvenile material. Compared to the monzogranites, the granodiorites are characterized by higher Sr (373-599 ppm), low Y (12.5-20.5 ppm), and Yb (1.21-2.04 ppm) contents, with relatively higher Sr/Y (26-32) ratios, analogous to those of modern adakitic rocks. The differences in geochemical characteristics between the monzogranites and granodiorites may reflect differences in the P-T conditions experienced by the two lithologies during partial melting. We propose that the latest Devonian monzogranites were possibly generated by partial melting of the Tianshan Mesoproterozoic basement rock with an influx of juvenile material in an arc setting. However, the granodiorites were likely related to the slab roll-back of subducted north Tianshan Ocean during the early Carboniferous. (C) 2016 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Publication name	GONDWANA RESEARCH, 47 188-199; SI 10.1016/j.gr.2016.02.012 JUL 2017
Author(s)	Yin, Jiyuan; Chen, Wen; Xiao, Wenjiao; Yuan, Chao; Zhang, Bin; Cai, Keda; Long, Xiaoping
Corresponding author(s)	YIN Jiyuan   yinjiyuan1983@163.com    -Chinese Acad Geol Sci, Inst Geol, Lab Isotope Thermochronol, Beijing 100037, Peoples R China  -Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China  -Chinese Acad Sci, Inst Geochem, State Key Lab Ore Deposit Geochem, Guiyang 550002, Peoples R China

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