Abstract
The major elements, trace elements and Nd-Sr isotopic composition of Cenozoic high-K igneous rocks and mafic deep-derived enclaves from the Liuhe-Xiangduo area, eastern Tibet, indicate the high-K igneous rocks are characterized as being enriched in Ca (CaO = 1.20% – 8.80%), alkali (Na2O + K2O =3.47% – 10.65%), especially K (K2O up to 5.96%) and depleted in Ti (TiO2 =0.27% – 1.50%). Their REE contents are very high (REE =91.29 – 231.11 μg/g). Their REE distribution patterns are of the right-inclined type, characterized by intense LREE enrichment [(La/Yb)N = 7.44 – 15.73]. The rocks are distinctly enriched in Rb, Sr and Ba (46.3 – 316 μg/g, 349–1220 μg/g and 386 – 2394 μg/g, respectively), high in U and Th (1.17 – 8.10 μg/g and 2.38 – 27.0 μg/g, respectively), moderate in Zr and Hf (87.5 – 241 μg/g and 2. 83 – 7.52 μg/g, respectively), and depleted in Nb and Ta (4.81 – 16.8 μg/g and 0.332 – 1.04 μg/g, respectively). In the primitive mantle-normalized incompatible element spidergram, U, K, Sr and Hf show positive anomalies, whereas Th, Nb, Ta, P, and Ti show negative anomalies. The rocks are strongly depleted in Cr and Ni (21.4 – 1470 μg/g and 7.79 – 562 μ/g, respectively), and their transition element distribution curves are obviously of type-W. The (87Sr/86Sr)i ratios range from 0.704184 to 0.707539; (143Nd/144Nd)i from 0.512265 to 0.512564; and εNd(t) from -6.3 to -0.4. These geochemical features might suggest that the potential source of the high-K igneous rocks in the Liuhe-Xiangduo area is similar to the EM2, which may be similar to the material enriched K that is located under the crust-mantle mixed layer. The mafic deep-derived enclaves in the high-K igneous rocks belong to chance xenoliths. Their (87Sr/86Sr)i ratios range from 0.706314 to 0.707198; (143Nd/144Nd), from 0.512947 to 0.513046; and εNd(t) from +7.0 to +9.0. These geochemical features might indicate that the enclaves probably came from the depleted mantle. TheP-T conditions of the enclaves also showed that the enclaves are middle-lower crust metamorphic rocks, which were accidentally captured at 20 – 50 km level by rapidly entrained high-K magma, whose source is over 50 km in depth.
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References
Cai Xinping (1992) Discovery of deep-derived xenoliths in Cenozoic al-kali-rich porphyries along the margin of the Yangtze platform and its significance [J].Scientia Geologica Sinica.27, 183–189 (in Chinese with English abstract).
Deng Wanming, Huang Xuan, and Zhong Dalai (1998) Alkali-rich porphyry and its relation with intraplate deformation of northern part of Jinsha River belt in western Yunnan, China [J].Science in China (Series D).28, 111–117 (in Chinese).
Gibson S. A., Thompson R. N., Dickin A. P., and Leonardos O. H. (1996) High-Ti and low-Ti mafic potassic magamas: Key to plumelithosphere interactions and continental flood-basalt genesis [J].Earth and Planetary Science Letters.141, 325–341.
Harrison T. M., Leloup P. H., Ryerson, F. J., Tapponnier P., Lacassin R., and Chen W. J. (1996) Diachronous initiation of transtension along the Ailao Shan-Red River shear zone, Yunnan and Vietnam. InThe Tectonic Evolution of Asia (eds. Yin An and T. M. Harrison) [C]. pp. 208 -226. Cambridge University Press, New York.
Hawkesworth C. J., Hammill M. A., Gledhill R., Calsteren P., and Rogers G. (1982) Isotope and trace element evidence for late-stage intra-crustal melting in the High Andes [J].Earth and Planetary Science Letters.58, 240–254.
Irvine T. N. and Baragar W. R. A. (1971) A guide to the chemical classification of the common volcanic rocks [J].Canadian Journal of Earth Sciences.8, 523–548.
Jagoutz E., Palme H., Baddenhausen H., Blum K., Cendales M., Dreibus G., Spottel B., Lorenz V., and Wanke H. (1979) The abundances of major, minor and trace elements in the earth’ s mantle as derived from primitive ultramafic nodules [J].Geochimica et Cosmochimica Acta. 11, 2031–2050.
Le Bas, M. J., Le Maitre R. W., Streckheisen A., and Zanettin B. (1986) A chemical classification of volcanic rocks based on the total alkali-silica diagram [J].Journal of Petrology.27, 745–750.
Le Maitre R. W., Bateman P., Dudek A., Keller J., Lameyre J., Le Bas M. J., Sabine P. A., Schmid R., Sorensen H., Streckeisen A., Woolley A. R., and Zanettin B. (1989)A Classification of Igneous Rocks and Glossary of Terms [M]. 193p. Blackwell Scientific Publication, Qxford.
Liang Xirong, Wei Gangjian, Li Xianhua, and Liu Ying (2003) Precise measurement of143Nd/144Nd and Sm/Nd ratios using multiple-collectors inductively coupled plasma-mass spectrometer (MC-ICPMS) [J].Geochimica.32, 91–96 (in Chinese with English abstract).
Liu Futian, Liu Jianhai, Zhong Dalai, He Jiankun, and You Qingyu (2000) The subducted salb of Yangtze continental block beneath the Tethyan orogen in western Yunnan [J].Chinese Science Bulletin.45, 466–471.
Liu Xianfan, Zhan Xinzhi, Gao Zhenmin, Liu Jiajun, Li Chaoyang, and Su Wenchao (1999) Deep xenoliths in alkalic porphyry, Liuhe, Yunnan, and implications to petrogenesis of alkalic porphyry and associated mineralizations [J].Science in China (Series D).29, 413 -420 (in Chinese).
Liu Ying, Liu Haichen, and Li Xianhua (1996) Simultaneous and precise determination of 40 trace elements in rock samples using ICP-MS [J]:Geochimica.25, 552–558 (in Chinese with English abstract).
Lü Boxi and Qian Xianggui (1999) Petrology study on deep-derived enclaves from Cenozoic alkalic volcanic rocks and alkali-rich porphyries in western Yunnan [J].Yunnan Geology.18, 127–143 (in Chinese).
Masek J. G., Isacks B. L., Fielding F. J., and Browaeys J. (1994) Rift flank uplift in Tibet: Evidence for a viscous lower crust [J].Tectonics.13, 659–667.
McDermott F. and Hawkesworth C. J. (1991) Th, Pb and Sr isotopic variations in young island arc volcanics and oceanic sediments [J].Earth and Planetary Science Letters.104, 1–15.
Meyer B. P., Tapponnier L., Bourjot F., Metivier Y., Gaudemer G., Peltzer S. M., and Chen Z. T. (1998) Crustal thickening in Gansu-Qinghai, Lithospheric mantle subduction, and oblique, strike-slip controlled growth of the Tibet Plateau [J].Geophysical Journal International.135, 1–47.
Pan Guitang, Wang Peisheng, and Xu Yaorong (1990)Cenozoic Tectonic Evolution of Qinhai-Xizang Plateau [M]. 190p. Geological Publishing House, Beijing (in Chinese).
Rickwood P. C. (1989) Boundary lines within petrologic diagrams which use oxides of major and minor elements [J].Lithos.22, 247–263.
Saunders A. D., Norry M. J., and Tarney J. (1988) Origin of MORB and chemically depleted mantle reservoirs: trace elements constraints [J].Journal of Petrology (Special Lithosphere Issue). 415–445.
Sun S. S. and McDonough W. F. (1989) Chemical and isotopic systematics of oceanic basalts; implications for mantle composition and processes. InMagmatism in the Ocean Basins (eds. A.D. Saunders and M. J. Norry) [C]. 345p. Geological Society Special Publication, London.
Vance D., Stone J. O. H., and O’ Nions R. K. (1989) He, Sr and Nd isotopes in xenoliths from Hawaii and other oceanic islands [J].Earth and Planetary Science Letters.96, 147–160.
Wang Jianghai, Yin An, Harrison T. M., Grove M., Zhang Yuquan, and Xie Guanghong (2001) A tectonic model for Cenozoic igneous activities in the eastern Indo-Asian collision zone [J].Earth and Planetary Science Letters.188, 123–133.
Wang Jian, Li Jianping, Wang Jianghai, and Ma Zhihong (2003) Geological implications for the deep-derived mafic enclaves from Cenozoic shoshonitic rocks in Jianchuan-Dali area, West Yunnan [J].Chinese Journal of Geochemistry.22, 58–73.
Wei Gangjian, Liang Xirong, Li Xianhua, and Liu Ying (2002) Precise measurement of Sr isotopic composition of liquid and solid base using (LP) MC-ICPMS [J].Geochimica.31, 295–299 (in Chinese with English abstract).
Wei Qirong (2002)Petrology and Geochemistry of the Xenoliths from Cenozoic Two-Pulse High-K Magmatic Rocks in Eastern Tibet:A Case Study of Xenoliths at Maguan and Liuhe in Yunnan [R]. pp. 74–77. Guangzhou, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Postdoctoral Study Report (in Chinese with English abstract).
Wei Qirong and Wang Jianghai (2004) Geochemical characteristics of Cenozoic basaltic high-K volcanic rocks from Maguan area, eastern Tibet [J].Chinese Journal of Geochemistry.23, 57–64.
Wilson M. (1989)Igneous Petrogenesis [M]. pp. 375–416. Oxford University Press, London.
Yin An (2000) Mode of Cenozoic east-west extension in Tibet suggesting a common origin of rifts in Asia during the Indo-Asian collision [J].Journal of Geophysical Research.105, 21745–21759.
Zhang Yuquan and Xie Yingwen (1997) Geochronology of Ailaoshan-Jin-shajiang alkali-rich intrusive rocks and their Sr and Nd isotopic characteristics [J].Science in China (Series D).27, 289–293 (in Chinese).
Zhu Bingquan (1998)Theory and Apllication of Isotopic Systematics in Earth Sciences [M]. pp. 194 -215. Science Press, Beijing (in Chinese with English abstract).
Zindler A. and Hart S. (1986) Chemical geodynamics [J].Annual Reviews of Earth and Planetary Science.14, 493–571.
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The study was supported jointly by the State Key Projects for Basic Research (No. G1998040807) and the Knowledge-innovation project of the Chinese Academy of Sciences (No. KZCX2-SW-117).
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Qirong, W., Jianghai, W. Geochemical characteristics of Cenozoic high-K igneous rocks from Liuhe-Xiangduo area, eastern Tibet. Chin. J. Geochem. 24, 158–165 (2005). https://doi.org/10.1007/BF02841160
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DOI: https://doi.org/10.1007/BF02841160