Geochronology,geochemistry and Nd-Hf isotopic compositions of the Kuqu leucogranite in the eastern Himalaya:Implications for the tectonic setting and rare metal mineralization
The Himalayan leucogranite is an excellent target for understanding orogenic process of the India-Asia collision.An integrated geochronological,geochemical and in situ Nd-Hf isotopic data are presented for the Kuqu leucogranite in the eastern Himalaya,Tibet.LA-ICP-MS U-Pb dating of zircon and monazite show that they were emplaced at～25 Ma.These leucogranites have high SiO2 and A12O3 contents of 73.32％to 74.53％and 14.72％to 15.25％,respectively.They are characterized by high aluminum saturation index of 1.14～1.23 and Rb/Sr ratios of 2.38～15.4,representative of highly fractionated granite.These leucogranites are enriched in large ion lithophile elements(e.g.,Rb,K and Pb),and depleted in high field strength elements(e.g.,Nb,Zr and Ti).They display low εNd(t)(-13.4 to-11.7)and εHf(t)(-10.4 to-7.86),consistent with isotopic characteristics of the higher Himalayan sequence.Their petrogenesis can be considered as highly fractionated melt derived from ancient basement from the higher Himalayan sequence in regional extension due to the activity of the South Tibetan detachment system.The significantly high lithium and beryllium content of the leucogranites and related pegmatites suggest that the Himalayan leucogranites have huge potential for the rare metal mineralization.
LeucogranitePetrogenesisRare metal mineralizationHimalaya
万方数据
维普
