SHRIMP U-Pb zircon geochronology of Neoproterozoic Korla mafic dykes in the northern Tarim Block, NW China: implications for the long-lasting breakup process of Rodinia

摘要

Mafic dykes are observed in the Korla region along the northern Tarim Block, NW China. Our sensitive high-resolution ion microprobe U–Pb zircon ages, the first determined for these dykes, indicate that the mafic dykes were mainly formed at 650–630 Ma, and thus document the youngest known igneous activity associated with rifting in the Tarim Block during the Neoproterozoic. Combined with previous geochronological data, at least three pulses of magmatic activity, from c. 830 to 800 Ma, from c. 790 to 740 Ma and from c. 650 to 630 Ma, are recognized, which reveal that multiple episodes of rifting occurred within the Tarim Block, implying that the breakup of the Rodinia supercontinent in the Tarim Block may have been a long-lasting process.