Sandstones of the Itmurundy accretionary complex, central Kazakhstan, as archives of arc magmatism and subduction erosion: Evidence from U-Pb zircon ages, geochemistry and Hf-Nd isotopes

Safonova, Inna; Perfilova, Alina; Savinskiy, Ilya; Котлер, П. Д.; Sun, Min; Wang, Bo

doi:10.1016/j.gr.2022.06.018

Cited by 8 publications

(18 citation statements)

References 66 publications

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“…A typical OPS succession includes: (i) pelagic chert often deposited directly onto oceanic basalts (mid-ocean ridge basalt, MORB, or oceanic island basalt, OIB); (ii) hemipelagic siliceous shale, greywacke and mudstone formed closer to a trench and (iii) trench turbidites. OPS turbidites typically occur in the upper parts of OPS packages [ 22 , 31 ]. Fore-arc and back-arc clastic formations contain greywacke sandstones, which can also be parts of banded turbidites or represent massive, not stratified, deposits.…”

Section: From Magmatic Arc To Sandstonementioning

confidence: 99%

“…Tectonically, they are part of the Junggar-Balkhash folded system in the western CAOB, formed by the suturing of the Junggar-Balkhash Ocean, a western branch of the Paleo-Asian Ocean [ 4 , 36 , 41 , 42 ]. The Itmurundy and Tekturmas belts host late Cambrian-Ordovician supra-subduction igneous complexes and Ordovician-to-early-Silurian accretionary complexes, which both, until recently, had remained poorly studied [ 31 , 32 , 43–48 ]. Both belts are composed of tectonic sheets separated by thrust and strike-slip faults.…”

Section: Geological Overview Of Central Kazakhstanmentioning

confidence: 99%

“…3 ). The middle-late Cambrian ophiolitic association includes ultramafic and mafic rocks (harzburgite, wherlite, dunite, gabbro) and serpentinite mélange hosting fragments of sedimentary (chert), metamorphic (amphibolite) and igneous (plagiogranite, diorite) rocks [ 31 , 43 , 45 , 48 , 50 ]. The accretionary complex includes Ordovician-to-early-Silurian OPS igneous and sedimentary rocks [ 37 ]: MORB- and OIB-type basalts, pelagic ribbon chert, hemipelagic siliceous mudstone and siltstone and trench turbidite [ 47 ].…”

Section: Geological Overview Of Central Kazakhstanmentioning

confidence: 99%

“…consists of thick fine-to-coarse-grained sandstone and gravelstone, siliceous siltstone, siliceous mudstone, chert and basalt. The late Ordovician–late Silurian age of the sandstones was determined by U-Pb detrital zircon ages [ 31 ], conodonts in chert [ 44 , 51 ] and graptolites in siltstone [ 52 ].…”

Section: Geological Overview Of Central Kazakhstanmentioning

confidence: 99%

“…Recently, more and more papers have been published on the composition, U-Pb zircon ages and Hf-in-zircon isotopes of sandstones from different orogens of the CAOB (Fig. 2 ): Altai [ 21 , 24 , 25 ], Tienshan [ 23 , 26–28 ], Mongolia [ 21 , 29 , 30 ] and Kazakhstan [ 22 , 31 , 32 ]. However, a lot of supra-subduction and turbiditic formations remain understudied.…”

Section: Introductionmentioning

confidence: 99%

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Survived and disappeared intra-oceanic arcs of the Paleo-Asian Ocean: evidence from Kazakhstan

Safonova

Perfilova

2022

National Science Review

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The paper reviews published and presents new data on U-Pb detrital zircon ages, petrographic, geochemical and isotope (Sm-Nd, Lu-Hf) compositions obtained from greywacke sandstones of Kazakhstan in order to reconstruct fossil intra-oceanic arcs once existed at Pacific-type convergent margins of the Paleo-Asian Ocean (PAO) in Paleozoic time. We focused on orogenic belts of central Kazakhstan (Itmurundy and Tekturmas) and eastern Kazakhstan (Zharma and Char) in the western Central Asian Orogenic belt (CAOB). These orogenic belts host accretionary complexes with greywacke sandstones of early Paleozoic (central Kazakhstan) and middle-late Paleozoic (eastern Kazakhstan) ages. First, we evaluate general perspectives for studying sandstones to reconstruct survived and disappeared magmatic arcs taking into account episodes of subduction erosion. Then we discuss the analytical data from sandstones to conclude about the ages and settings of formation of their igneous protoliths and define maximum deposition ages. Finally, we discuss the role of serpentinite mélange in tectonic reconstructions. We argue that sandstones hosted by accretionary complexes are typically greywackes deposited close to their igneous sources and buried rapidly. The provenances of the studied greywacke sandstones of central and eastern Kazakhstan were dominated by mafic to andesitic igneous protoliths derived from juvenile mantle sources. The igneous rocks in the provenances were emplaced in an intra-oceanic arc setting. The sandstones were deposited in fore-arc/trench basins or, to a lesser degree, in back-arc basins. The data from both sandstones and serpentinite mélange reconstruct middle-late Cambrian, Ordovician, late Devonian and Carboniferous arcs of the western PAO. The middle-late Cambrian arcs were fully destroyed by subduction erosion, whereas the Ordovician and Carboniferous arcs survived. The late Devonian arcs were also eroded, but partly. Both, the early and late Paleozoic active margins of the PAO were characterized by alternating periods of accretionary growth and subduction erosion.

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Section: From Magmatic Arc To Sandstonementioning

confidence: 99%