Late Paleozoic–Mesozoic tectonic evolution of the Trans-Altai and South Gobi Zones in southern Mongolia based on structural and geochronological data

Alfonso, Guy; Schulmann, Karel; Clauer, Norbert; Hasalová, Pavlína; Seltmann, Reimar; Armstrong, Robin; Lexa, Ondrej; Benedicto, Antonio

doi:10.1016/j.gr.2013.03.014

Cited by 73 publications

(81 citation statements)

References 51 publications

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“…The formation of the Main Mongolian Lineament and the Gobi-Tien Shan rift zones corresponded to early evolution of this rift system (Kuzmin et al 2011). Recent geophysical study (Guy et al 2014a(Guy et al , 2015 showed that the presumed rift systems coincide with intense magnetic lineaments suggesting existence of deep-seated tectonomagmatic zones. These zones are probably connected to a giant source located deep in the mantle as indicated by the gravity signal.…”

Section: Introductionmentioning

confidence: 94%

“…The Sagsai Pluton belongs to a series of Late Carboniferous to Permian granitoids which form a linear E-W belt along the contact of the Mongol Altai and Trans-Altai tectonic zones (Kovalenko et al 2006;Guy et al 2014a). Geophysical study of Guy et al (2014b) has shown that this tectono-magmatic zone spatially coincides with a strong, c. 15-20 km deep magnetic lineament.…”

Section: Geodynamic Contextmentioning

confidence: 99%

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Petrogenesis of the Late Carboniferous Sagsai Pluton in the SE Mongolian Altai

Buriánek¹,

Janoušek²,

Hanžl³

et al. 2016

J. Geosci.

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Sagsai Pluton intruded the low-grade metavolcanosedimentary complex of the Cambrian Tugrug Fm. in the Sagsai river valley SW of Tsogt soum, Gobi-Altai aimag (SE Mongolian Altai). This oval body (~9 × 12 km) is composed mainly of amphibole monzogabbros to quartz diorites, biotite to amphibole-biotite syenites to quartz monzonites. It is intruded by anatectic two-mica granites along the W rim. The abundant mafic microgranular enclaves enclosed by syenites to quartz monzonites are interpreted as an evidence of vigorous magma mingling and mixing. The newly obtained LA ICP-MS zircon ages for two samples of quartz monzonites gave emplacement ages of 307 ± 1 Ma and 309 ± 2 Ma (2σ), respectively. The zircons highly have ε t Hf values varying broadly from +2.4 to +11.6 ruling out a participation of an old, mature crust. One gabbro body gave zircon U-Pb age of 322 ± 2 Ma with positive ε t Hf values of +7.4 to +11.5. The latter suggest an exclusively juvenile, depleted mantle-derived magma source. According to calculated P-T conditions, we propose three main stages in the Sagsai Pluton evolution. The gabbro started to grow at >1000 °C and 0.8-0.9 GPa. The ensuing magma mixing with crustal melts and final crystallization of gabbro occurred at similar P-T conditions (740-830 °C and 0.5-0.6 GPa) as partial melting of migmatite xenoliths in the Sagsai Pluton. The P-T conditions of the Sagsai Pluton final emplacement calculated from quartz syenite (c. 600 to 670 °C and 0.4-0.5 GPa) are consistent with the mineral assemblage in the contact aureole (cordierite-biotite and biotite-chlorite schists). The magmatic evolution of Sagsai Pluton confirms a model of deep lithosphere thermal anomaly associated with heterogeneous melting of crust in a post-subduction extensional regime, perhaps shortly after the slab break-off.

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Section: Introductionmentioning

confidence: 94%

Section: Geodynamic Contextmentioning

confidence: 99%

Petrogenesis of the Late Carboniferous Sagsai Pluton in the SE Mongolian Altai

Buriánek¹,

Janoušek²,

Hanžl³

et al. 2016

J. Geosci.

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“…The continental crust of southern Mongolia and the Beishan region consists of a Paleoproterozoic basement complex in southern Mongolia surrounded by various lower through upper Paleozoic arc, accretionary prism/melange, and ophiolitic complexes [4,9,19,20]. Terrane maps of Mongolia with accompanying stratigraphic columns and geochronological data provide a regional lithotectonic framework for understanding the region's crustal evolution [4,21].…”

Section: Paleozoic Terrane Assembly Of the Southern Caob In The Gobi mentioning

confidence: 99%

“…Collision-related crustal shortening likely persisted into the Triassic [5,8,18]. It is proposed that CAOB terrane amalgamation in southern Mongolia throughout the Paleozoic occurred along a north-south oriented active margin and that the accreted terrane assemblage was subsequently oroclinally bent in a counterclockwise sense during the Permo-Triassic into an east-west orientation and cut by sinistral strike-slip faults in the Triassic-mid Jurassic [8,9,24,26,27]. The terrane amalgamation history of southern Mongolia and the Beishan region imparted a dominant east-west structural grain throughout the region (modern coordinates) consisting of terrane boundaries (including suture belts), other faults, metamorphic foliation and sedimentary strike belt trends, and magmatic arc trends [4,8,9,28].…”

Section: Paleozoic Terrane Assembly Of the Southern Caob In The Gobi mentioning

confidence: 99%

Folded Basinal Compartments of the Southern Mongolian Borderland: A Structural Archive of the Final Consolidation of the Central Asian Orogenic Belt

Cunningham

2017

Geosciences

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Abstract:The Central Asian Orogenic Belt (CAOB) records multiple Phanerozoic tectonic events involving consolidation of disparate terranes and cratonic blocks and subsequent reactivation of Eurasia's continental interior. The final amalgamation of the CAOB terrane collage involved diachronous closure of the Permian-Triassic Solonker suture in northernmost China and the Jurassic Mongol-Okhotsk suture in northeast Mongolia and eastern Siberia. The distribution, style, and kinematics of deformation associated with these two terminal collision events is poorly documented in southern Mongolia and northernmost China because these regions were later tectonically overprinted by widespread Cretaceous basin and range-style crustal extension and Miocene-recent sinistral transpressional mountain building. These younger events structurally compartmentalized the crust into uplifted crystalline basement blocks and intermontane basins. Consequently, widespread Cretaceous and Late Cenozoic clastic sedimentary deposits overlie older Permian-Jurassic sedimentary rocks in most basinal areas and obscure the deformation record associated with Permian-Triassic Solonker and Jurassic Mongol-Okhotsk collisional suturing. In this report, satellite image mapping of basinal compartments that expose folded Permian-Jurassic sedimentary successions that are unconformably overlapped by Cretaceous-Quaternary clastic sediments is presented for remote and poorly studied regions of southern Mongolia and two areas of the Beishan. The largest folds are tens of kilometers in strike length, east-west trending, and reveal north-south Late Jurassic shortening (present coordinates). Late Jurassic fold vergence is dominantly northerly in the southern Gobi Altai within a regional-scale fold-and-thrust belt. Local refolding of older Permian north-south trending folds is also evident in some areas. The folds identified and mapped in this study provide new evidence for the regional distribution and kinematics of Jurassic and Permian-Triassic contractional tectonism in the southern Mongolia-northern China borderland region. The newly mapped folds are also important potential targets for hydrocarbon exploration and vertebrate paleontological discoveries.

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“…This pervasive fabric is refolded by open to closed, upright folds with steep NW-SE trending axial planar cleavage (S 2 ). Kröner et al (2010), Guy et al (2014) and Hanžl et al (2016). MML, Main Mongolian Lineament.…”

Section: Tugrug Formationmentioning

confidence: 99%

Geology of the Gobi Altai and Tseel terranes in the central part of the Sagsai River Watershed, SE Mongolian Altai

et al. 2017

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A geological map is an indispensable tool for understanding the structure of the Earth's crust but high-quality geological maps are usually lacking in remote areas of mountainous Central Asia covered by vast deserts. The progress in remote sensing and geographical information system (GIS), as well as the advancement in analytical methods, have generated new challenges in producing modern geological maps in such regions. The presented 1:50,000 geological map along the Sagsai River summarizes new and more accurate geological data from the geologically interesting region at the contact of the supracrustal and deep crustal Tugrug and Tseel units forming the metamorphosed accretionary wedge on the S and SW slopes of the Mongolian Altai. These geological units are formed by the lower Palaeozoic volcano-sedimentary sequences affected by Devonian Barrovian metamorphism ranging from lower greenschist to granulite facies. This metamorphic basement was subsequently intruded by the post-orogenic late Carboniferous Sagsai Pluton. The presented map shows complex relationships between different crustal levels of the metamorphosed accretionary wedge and post-tectonic intrusion evaluated using a GIS, numerical processing of remote sensing data as well as field documentation and laboratory studies. ARTICLE HISTORY

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Late Paleozoic–Mesozoic tectonic evolution of the Trans-Altai and South Gobi Zones in southern Mongolia based on structural and geochronological data

Cited by 73 publications

References 51 publications

Petrogenesis of the Late Carboniferous Sagsai Pluton in the SE Mongolian Altai

Petrogenesis of the Late Carboniferous Sagsai Pluton in the SE Mongolian Altai

Folded Basinal Compartments of the Southern Mongolian Borderland: A Structural Archive of the Final Consolidation of the Central Asian Orogenic Belt

Geology of the Gobi Altai and Tseel terranes in the central part of the Sagsai River Watershed, SE Mongolian Altai

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