Neoproterozoic magmatism in eastern Himalayan terrane

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2017,（6）
• 页码范围: 415-424
• 页数: 10页
• 语种: 英文

摘要

Geochronological investigation on gneisses of granitic to leucogranitic compositions in Cuona,south Tibet,reveal that their protoliths formed at 808.8 ± 7.9-816.4 ± 3.4 Ma and 855.8 ± 7.0 Ma,respectively.Zircon rims from the granitic gneiss record a metamorphic age of 739.4 ± 4.3 Ma.Lu-Hf isotopic analyses on zircon grains with Neoproterozoic ages yield negative εHf(t) values from-9.0 to-4.2,and the corresponding two-stage Hf model ages are 1965-2228 Ma.Whole-rock geochemical data indicate that all granitic gneisses are K-riched calc-alkali series.These new data together with literature data show that (1) the Himalayan terrane experienced an episode of Neoproterozoic magmatism at 850-800 Ma;(2) the Neoproterozoic magma of granitic compositions were derived from partial melting of ancient crusts,possibly due to the thermal perturbation related with the breakup of the Rodinia supercontinent.