Oroclinal buckling and associated lithospheric-scale material flow – insights from physical modelling: Implication for the Mongol-Hingan orocline

Abstract

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Modes and geometry of crustal-scale detachment folding in hot orogens—Insights from physical modeling

“…Finally, the progressive development of domes and melt migration, as shown in our models, suggests a decreasing age of both intrusive bodies and retrograde metamorphic events for mantling rocks along the series of the detachment folds from the collisional front (orogenic core) to the foreland. This can be seen in the spatial distribution of progressively younger domes in the Mongol-Altai Zone along a S-N direction towards the core of the Mongolian orocline (Figures 9D,10; reader can also compare NE-SW and NW-SE sections at Figures 15 and 16 in Jiang et al, 2019) and can be associated with its early (Devonian) formative stage to Permo-Triassic amplification (Jiang et al, 2019;Krýza et al, 2021). Here, the gradient of ages for Mongol-Altai domes comprises a sequence of older intrusions (360 Ma-340 Ma) for the Chandmann dome (Lehmann et al, 2017).…”

“…In particular, the Central Asian Orogenic Belt (CAOB), the largest accretionary complex on Earth, contains several kilometer-scale migmatitic to granulitic magmatic-metamorphic domes, e.g., the Chandmann dome (Lehmann et al, 2017); Bugat dome (Cai et al, 2015) or Tseel dome (Jiang et al, 2012;Burenjargal et al, 2016;Hong et al, 2021). These structures were initiated in response to the early formative stages (Silurian-Devonian) of the Mongol-Altai zone, and amplified during closing of the Mongol-Okhotsk oceanic domain during development of the Mongol-Hingan orocline in the Permian-Triassic (Jiang et al, 2016;Jiang et al, 2019;Krýza et al, 2021). These dome-fold structures were interpreted as large buckle folds of the lower anatectic felsic crust enveloped by medium and low grade metasedimentary units.…”

Deformational History of the Kanguer Subduction Complex in the Eastern Tianshan (NW China): Implications for Paleozoic‐Triassic Multiple Accretionary Tectonics of the Southern Altaids

“…The Altaids were formed by successive accretion (∼1.0 Ga ‐ 210 Ma) of island arcs, continental arcs, seamounts, microcontinents, and accretionary complexes (Dobretsov et al., 1995; Şengör et al., 1993; Windley et al., 2007; Xiao et al., 2018). Final ocean closure and consolidation of the Eurasian continent is thought to have accompanied convergence of the Tarim and North China cratons along the South Tianshan‐Eastern Tianshan‐Beishan‐Solonker suture zone (Krýza et al., 2021; Liu et al., 2021; Şengör et al., 1993; Xiao et al., 2018). However, the timing of the final amalgamation of these continental blocks is highly controversial, especially in the Eastern Tianshan, where estimates of timing vary from Carboniferous to Permo‐Triassic (Ao et al., 2021; Mao, Ao, Windley, Zhang, et al., 2022; Qin et al., 2011; B. Wang et al., 2014; Xia et al., 2004; Xiao et al., 2004; M. F. Zhou et al., 2004).…”