Structural evolution of the Bayanhongor region, west-central Mongolia

Osozawa, Soichi; Tsolmon, G.; Majigsuren, Uondon; Sereenen, Jargalan; NIITSUMA, Shigeaki; Iwata, Naoyoshi; Pavlis, Terry L.; Jahn, Bor‐ming

doi:10.1016/j.jseaes.2008.01.003

Cited by 24 publications

(40 citation statements)

References 23 publications

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“…2; Osozawa et al, 2008, and references therein). The overall regional structural pattern is dominated by northwest-striking and northeast-vergent thrust faults (Buchan et al, 2001;Osozawa et al, 2008), which separate six major lithotectonic units ( Fig. 2; Buchan et al, 2001).…”

Section: Accretionary Domain Ne Of the Baydrag Blockmentioning

confidence: 99%

“…From SW to NE, these six units are as follows, and details of lithologies as well as structural and stratigraphic relations were provided by Buchan et al (2001) and Osozawa et al (2008).…”

Section: Accretionary Domain Ne Of the Baydrag Blockmentioning

confidence: 99%

“…1). The Baydrag block is surrounded by late Neoproterozoic to Palaeozoic tectonic units reflecting ocean closure, accretion and collision during terrane amalgamation in the CAOB, predominantly in the Palaeozoic (Buchan et al, 2001;Osozawa et al, 2008;Demoux et al, 2009a;Jian et al, 2010). The Bayankhongor ophiolitic domain occurs NE of the Baydrag block from which it is separated by thrust faults (Fig.…”

Section: Introductionmentioning

confidence: 99%

“…2a and b), and the ophiolite belt is followed to the NE by the wide Hangay basin Fig. 2a consisting of a monotonous sequence of Carboniferous sandstone and mudstone with rare chert beds (Kelty et al, 2008;Osozawa et al, 2008) and presumably underlain by crystalline basement of the Hangay microcontinent whose northern part is known as the Tarvagatay block (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

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Zircon ages for a felsic volcanic rock and arc-related early Palaeozoic sediments on the margin of the Baydrag microcontinent, central Asian orogenic belt, Mongolia

Kröner

Demoux

Zack

et al. 2011

Journal of Asian Earth Sciences

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Section: Accretionary Domain Ne Of the Baydrag Blockmentioning

confidence: 99%

“…From SW to NE, these six units are as follows, and details of lithologies as well as structural and stratigraphic relations were provided by Buchan et al (2001) and Osozawa et al (2008).…”

Section: Accretionary Domain Ne Of the Baydrag Blockmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Zircon ages for a felsic volcanic rock and arc-related early Palaeozoic sediments on the margin of the Baydrag microcontinent, central Asian orogenic belt, Mongolia

Kröner

Demoux

Zack

et al. 2011

Journal of Asian Earth Sciences

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“…An oceanic plateau was generated in the pelagic region (probably below the carbonate compensation depth) of the Hangay -Hentey paleo -ocean during the Devonian and it also implies that the ocean was wide. The subduction direction was probably the same as that for the Bayanhongor ophiolite zone, where SW -dipping and NE -vergent thrusting occurred (Buchan, 2001;Tomurtogoo, 2006;Osozawa et al, 2008). During subduction of the oceanic crust beneath the active continental margin of the Central Mongolian (or Tuva -Mongolian) Massif, probably in the Early Carboniferous, the oceanic plateau approached the subduction zone and jammed in the trench.…”

Section: Geotectonic Implicationsmentioning

confidence: 91%

Middle Paleozoic greenstones of the Hangay region, central Mongolia: Remnants of an accreted oceanic plateau and forearc magmatism

Erdenesaihan

Ishiwatari

Orolmaa

et al. 2013

Journal of Mineralogical and Petrological Sciences

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The Hangay -Hentey belt in Central Mongolia constitutes a Pacific -type accretionary orogen that formed through the evolution and closure of the Hangay -Hentey paleo -ocean during the Early Paleozoic to Early Mesozoic. From this belt, new geochemical and petrological results are presented for greenstones from the Erdenetsogt Formation hosted by the Tsetserleg accretionary terrane in the Hangay region, with particular emphasis on newly found picritic and andesitic rocks. These rocks occur mostly in the lower portion of the Erdenetsogt Formation as massive lavas, sills, and dikes closely associated with varicolored bedded ribbon cherts and siltstones. The protoliths of the studied greenstones comprise (1) enriched, plume -derived tholeiitic greenstones including picrites and ferrobasalts with oceanic plateau basalt affinity, (2) non -enriched, plume -derived tholeiitic basalts with E -MORB affinity, and (3) arc -derived high -Mg andesites (HMAs). The plume -derived rocks are characterized by chemical signatures such as slight LREE enrichment similar to that of tholeiitic OIB and the existence of ferropicrite with high FeO* (>14 wt%) and MgO (12 -22 wt%), which is characteristic of large igneous provinces (LIPs), including oceanic plateaus. Their tholeiitic composition and high -Fe and -Ti contents require melting of the source mantle peridotite with addition of some recycled Fe -and Ti -rich basaltic material. The non -enriched basalts may have been generated by a higher degree of melting of the same source mantle. The HMAs are characterized by glassy texture, high MgO content (up to 7 wt%), and significant LREE enrichment with depletion in Nb and resemble sanukite of the Setouchi volcanic belt, SW Japan. We infer that the Hangay tholeiitic greenstones probably represent an accreted upper section of an oceanic plateau that developed in the deep -water region of the Hangay -Hentey paleo -ocean in the Devonian. The Hangay HMAs may have been produced by subduction of young oceanic plate after an oceanward back -stepping of the subduction zone that was a result of the collision during the Carboniferous of the oceanic plateau and the active continental margin of the Central Mongolian Massif.

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Neoproterozoic‐Early Paleozoic Peri‐Pacific Accretionary Evolution of the Mongolian Collage System: Insights From Geochemical and U‐Pb Zircon Data From the Ordovician Sedimentary Wedge in the Mongolian Altai

et al. 2017

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Neoproterozoic to early Paleozoic accretionary processes of the Central Asian Orogenic Belt have been evaluated so far mainly using the geology of ophiolites and/or magmatic arcs. Thus, the knowledge of the nature and evolution of associated sedimentary prisms remains fragmentary. We carried out an integrated geological, geochemical, and zircon U‐Pb geochronological study on a giant Ordovician metasedimentary succession of the Mongolian Altai Mountains. This succession is characterized by dominant terrigenous components mixed with volcanogenic material. It is chemically immature, compositionally analogous to graywacke, and marked by significant input of felsic to intermediate arc components, pointing to an active continental margin depositional setting. Detrital zircon U‐Pb ages suggest a source dominated by products of early Paleozoic magmatism prevailing during the Cambrian‐Ordovician and culminating at circa 500 Ma. We propose that the Ordovician succession forms an “Altai sedimentary wedge,” the evolution of which can be linked to the geodynamics of the margins of the Mongolian Precambrian Zavhan‐Baydrag blocks. This involved subduction reversal from southward subduction of a passive continental margin (Early Cambrian) to the development of the “Ikh‐Mongol Magmatic Arc System” and the giant Altai sedimentary wedge above a north dipping subduction zone (Late Cambrian‐Ordovician). Such a dynamic process resembles the tectonic evolution of the peri‐Pacific accretionary Terra Australis Orogen. A new model reconciling the Baikalian metamorphic belt along the southern Siberian Craton with peri‐Pacific Altai accretionary systems fringing the Mongolian microcontinents is proposed to explain the Cambro‐Ordovician geodynamic evolution of the Mongolian collage system.

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Structural evolution of the Bayanhongor region, west-central Mongolia

Cited by 24 publications

References 23 publications

Zircon ages for a felsic volcanic rock and arc-related early Palaeozoic sediments on the margin of the Baydrag microcontinent, central Asian orogenic belt, Mongolia

Zircon ages for a felsic volcanic rock and arc-related early Palaeozoic sediments on the margin of the Baydrag microcontinent, central Asian orogenic belt, Mongolia

Middle Paleozoic greenstones of the Hangay region, central Mongolia: Remnants of an accreted oceanic plateau and forearc magmatism

Neoproterozoic‐Early Paleozoic Peri‐Pacific Accretionary Evolution of the Mongolian Collage System: Insights From Geochemical and U‐Pb Zircon Data From the Ordovician Sedimentary Wedge in the Mongolian Altai

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