地质通报Issue(1)：91-103,13.
藏南错那淡色花岗岩LA-MC-ICP-MS锆石U-Pb年龄、岩石地球化学及其地质意义
摘要
Abstract
The Cuona leucogranite pluton is situated in the east of Himalayan orogen. LA-MC-ICP-MS zircon U-Pb dating re⁃veals that leucogranites were crystallized at 17.7±0.3Ma, representing the Miocene crustal anataxis. Geochemical studies show that the samples are characterized by high SiO2 (74.46%~75.57%), Al2O3 (14.07%~14.64%), K2O (4.19%~4.85%), K2O/Na2O ratios (1.09~1.31) and A/CNK values (1.15~1.25), enrichment of Rb, Th, U and depletion of Ba, Nb, Zr, Sr, and high ratios of Rb/Sr (17.75~29.50) with strong negative Eu anomalies (δEu=0.18~0.26). These features suggest that they are crust-derived high potassium calc-alkaline and peraluminous S-type granite. The relatively high Isr (0.78982~0.79276) and lowεNd(t) (-19.5~-18.2) are well compara⁃ble with data of the metapelite from Greater Himalayan Crystalline complex (GHC), indicating that the leucogranites were generated from their partial melting. The features of high Isr and low Sr concentration as well as the decreasing Rb/Sr values with increasing Ba concentration demonstrate that the Cuona leucogranites were derived from muscovite dehydration melting under the water-absent condition, possibly triggered by structural decompression responding to the activity of South Tibetan Detachment system (STDS). It is held that the Cuona leucogranites reflect dynamics of structural decompression, dehydration melting and emplacement of the melt along STDS under the background of crustal extension and thinning.关键词
错那淡色花岗岩/LA-MC-ICP-MS/锆石U-Pb定年/Sr-Nd同位素/形成机制/藏南Key words
Cuona leucogranite/LA-MC-ICP-MS/zircon U-Pb dating/Sr-Nd isotopes/formation mechanism/southern Tibet分类
天文与地球科学引用本文复制引用
王晓先,张进江,闫淑玉,刘江..藏南错那淡色花岗岩LA-MC-ICP-MS锆石U-Pb年龄、岩石地球化学及其地质意义[J].地质通报,2016,(1):91-103,13.基金项目
中国地震局地壳应力研究所中央级公益性科研院所基本科研业务专项（编号ZDJ2014-09）和国家自然科学基金项目 （）
