首页|Cenozoic Adakite-type Volcanic Rocks in Qiangtang,Tibet and Its Significance

Cenozoic Adakite-type Volcanic Rocks in Qiangtang,Tibet and Its Significance

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Volcanic rocks in the study area, including dacite, trachyandesite and mugearite, belong to the intermediate-acid, high-K calc-alkaline series, and possess the characteristics of adakite. The geochemistry of the rocks shows that therocks are characterized by SiO2＞59%, enrichment in Al2O3 (15.09-15.64%) and Na2O (＞3.6%), high Sr (649-885 μg/g)and Sc, low Y contents (＜17 μg/g), depletion in HREE (Yb＜1.22 μg/g), (La/Yb)N＞25, Sr/Y＞40, MgO＜3% (Mg#＜0.35),weak Eu anomaly (Eu/Eu*=0.84-0.94), and lack of the high field strength elements (HFSE) (Nb, Ta, Ti, etc.). The Nd andSr isotope data (87Sr/86Sr=0.7062-0.7079, 143Nd/144Nd=0.51166-0.51253, εNd= -18.61-0.02), show that the magmaresulted from partial melting (10%-40%) of newly underplated basaltic lower crust under high pressure (1-4 GPa), and thepetrogenesis is obviously affected by the crust's assimilation and fractional crystallization (AFC). This research will givean insight into the uplift mechanism of the Tibetan plateau.

Cenozoiclower crusthigh-K calc-alkaline volcanic rockunderplatingpartial meltinguplift of plateauQiangtangTibet

Liu Shen、HU Ruizhong、Feng Caixia、Chi Xiaoguo、LI Cai、YANG Rihong、Wang Tianwu、JIN Wei

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Guiyang Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, Guizhou 550002

Graduate School of the Chinese Academy of Sciences, Beijing 100039

College of Earth Sciences, Jilin University, Changchun, Jilin 130026

Aero Geophysical & Remote Sensing Center, Beijing 100083

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国家重点基础研究发展计划(973计划)Project of Knowledge Innovation sponsored by the Chinese Academy of Sciences国家杰出青年科学基金

9501101-5KZCX2-10249925309

2003

地质学报(英文版)
中国地质学会

地质学报(英文版)

影响因子：1.414
ISSN：1000-9515
年,卷(期)：2003.77(2)
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