Asia: A frontier for a future supercontinent Amasia

Inna Safonova, Shigenori Maruyama

    Research output: Contribution to journalReview article

    30 Citations (Scopus)

    Abstract

    Asia is the worlds largest but youngest continent, in which Pacific-type (P-type) and collision-type (C-type) orogenic belts coexist with numerous amalgamated continental blocks. P-type orogens represent major sites of continental growth through tonalite-trondhjemite-granodiorite type (TTG-type) juvenile granitoid magmatism and accretion of oceanic crust and intra-oceanic arcs. The Asian continent includes several P-type orogenic belts, of which the largest are the Central Asian and Western Pacific. The Central Asian Orogenic Belt is dominated by P-type fossil orogens arranged with a regular northward subduction polarity. The Western Pacific is characterized by ongoing P-type orogeny related to the westward subduction of the Pacific plate. Asia has a multi-cratonic structure and its post-Palaeozoic history has witnessed amalgamation of the Laurasia composite continent and Pangaea supercontinent. Nowadays, Asia is surrounded by double-sided subduction zones, which generate new TTG-type crust and supply oceanic crust and microcontinents to its active margins. The TTG-crust can be tectonically eroded and subducted down to the mantle transition zone to form a second continent, which may generate mantle upwelling, plumes, and extensive intra-plate volcanism. Moreover, recent plate movements around Asia are dominated by northward directions, which resulted in the India-Eurasia and Arabia-Eurasia collisions beginning at 50-45 and 23-20 Ma, respectively, and will result in Africa-Eurasia collision in the near future. Therefore, Asia is the best candidate to serve as the nucleus for a future supercontinent Amasia, likely to form 200-250 Ma in the future. In this paper we unravel a puzzle of continental growth in Asia through P-type orogeny by discussing its tectonic history and geological structure, subduction polarity in P-type orogens, tectonic erosion of TTG-type crust and arc subduction at convergent margins, generation of mantle plumes, and prospects of Asia growth and overgrowth.

    Original languageEnglish
    Pages (from-to)1051-1071
    Number of pages21
    JournalInternational Geology Review
    Volume56
    Issue number9
    DOIs
    Publication statusPublished - Jul 4 2014

    Keywords

    • 'second' continent
    • Pacific-type orogeny
    • collision-type orogeny
    • double-sided subduction
    • mantle plume
    • mantle transition zone
    • tectonic erosion

    ASJC Scopus subject areas

    • Geology

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