Adakites from continental collision zones: Melting of thickened lower crust beneath southern Tibet

Sun Lin Chung, Dunyi Liu, Jianqing Ji, Mei Fei Chu, Hao Yang Lee, Da Jen Wen, Ching Hua Lo, Tung Yi Lee, Qing Qian, Qi Zhang

Research output: Contribution to journalArticle

766 Citations (Scopus)

Abstract

Adakites are geochemically distinct intermediate to felsic lavas found exclusively in subduction zones. Here we report the first example of such magmas from southern Tibet in an active continental collision environment. The Tibetan adakites were emplaced from ca. 26 to 10 Ma, and their overall geochemical characteristics suggest an origin by melting of eclogites and/or garnet amphibolites in the lower part (≥50 km) of thickened Tibetan crust. This lower-crustal melting required a significantly elevated geotherm, which we attribute to removal of the tectonically thickened lithospheric mantle in late Oligocene time. The identification of collision-type adakites from southern Tibet lends new constraints to not only the Himalayan-Tibetan orogenesis-how and when the Indian lithosphere started underthrusting Asia can be depicted-but also the growth of the early continental crust on Earth that consists dominantly of the tonalite-trondhjemite-granodiorite suites marked by adakitic geochemical affinities.

Original languageEnglish
Pages (from-to)1021-1024
Number of pages4
JournalGeology
Volume31
Issue number11
DOIs
Publication statusPublished - 2003 Nov 1

    Fingerprint

Keywords

  • Adakite
  • Continental collision
  • Lower-crustal melting
  • Tibet

ASJC Scopus subject areas

  • Geology

Cite this

Chung, S. L., Liu, D., Ji, J., Chu, M. F., Lee, H. Y., Wen, D. J., Lo, C. H., Lee, T. Y., Qian, Q., & Zhang, Q. (2003). Adakites from continental collision zones: Melting of thickened lower crust beneath southern Tibet. Geology, 31(11), 1021-1024. https://doi.org/10.1130/G19796.1