Zircon SHRIMP U-Pb Dating and Lu-Hf Isotopic Composition for Early Cretaceous Plutonic Rocks in amespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />ace w:st="on">Tengchong Block, ate w:st="on">Southeasternate> Tibetace>, and Its Tectonic Implications
摘要
AN id=EnChDivSummary name="EnDivSummary">The Early Cretaceous granodiorite and quartz monzonite are the main types of igneous rocks in Tengchong block. The characteristics of I-type plutonic rocks are shown by the mineral assemblages, and high Na2O and low K2O contents and A/CNK values. Zircon SHRIMP U-Pb dating show the granodiorite and quartz monzonite emplaced at (122±1.3) Ma and (125±1.3) Ma, respectively. The zircon εHf(t) values for granodiorite and quartz monzonite range from -9.6 to -4.8 (average -6.7±0.7) and -7.8 to -4.7 (average -6.3±0.6), with corresponding single-stage model ages ranging from 979 to 1 190 Ma and 975 to 1 113 Ma, respectively.