Mesoproterozoic juvenile crust in microcontinents of the Central Asian Orogenic Belt: evidence from oxygen and hafnium isotopes in zircon.

ABSTRACT: We report in situ O and Hf isotope data of zircon grains from coeval Mesoproterozoic (ca. 1.4 Ga) igneous metamafic (amphibolite) and granitic rocks of the Chinese Central Tianshan microcontinent (CTM) in the southern Central Asian Orogenic Belt (CAOB). Zircon grains from amphibolite have mantle-like δ¹⁸O_VSMOW values of 4.7-5.6‰ and juvenile Hf isotopic compositions (ε_Hf(t) = 8.4-15.3; T_DMC = 1.57-1.22 Ga), whereas those from granitic rocks have δ¹⁸O_VSMOW values of 5.6-7.0‰ and evolved Hf isotopic compositions (ε_Hf(t) = -1.0-8.2; T_DMC = 2.09-1.62 Ga). Zircon O-Hf isotopic compositions of the metamafic and granitic rocks provide evidence for Mesoproterozoic (ca. 1.4 Ga) crustal growth and a substantial P

SUBMITTER: He ZY 

PROVIDER: S-EPMC5864758 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature