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

Abstract

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.

The Shalap Mélange of the Salairian Alambay Ophiolite Zone (Northwestern Central Asian Orogenic Belt), Geological Structure and Compositional Features of Amphibolites and Greenstone Basalts

“…осадков, встречающиеся в поле развития меланжа, в отличие от блоков микрокварцитов, известняков, серпентинитов и амфиболитов, не являются включениями, сингенетичными офиолитовому меланжу. В пользу этого свидетельствует состав матрикса терригенного меланжа, представленный нормально-осадочными породами, подвергшимися тектонической переработке в различной степени, состав блоков-включений в меланже и ряд геологических особенностей, позволяющих относить шалапский меланж к категории субдукционных меланжей [Festa et al, 2010;Raymond, 2019] (по [Dobretsov et al, 2004;State Geological Map…, 2019;Zhimulev et al, 2023]). 1 -нижнемеловые отложения Неня-Чумышского прогиба; 2-5 -деформированные фрагменты чехла Салаира: 2 -верхнедевонско-нижнекарбоновые песчаники и алевролиты Хмелевского прогиба, 3 -девонские известняки и песчаники, 4 -силурийско-девонские известняки и песчаники, 5 -ордовикские песчаники; 6 -среднекембрийско-нижнеордовикские туфы, лавы и песчаники островодужного происхождения; 7 -нижнекембрийские туфы, лавы и песчаники островодужного происхождения; 8 -венд-нижнекембрийские углеродистые сланцы, алевролиты, микрокварциты и известняки (осадочная часть офиолитового разреза и карбонатная шапка палеоострова); 9 -блоки нижнекембрийских известняков в меланже; 10 -офиолитовое габбро; 11 -серпентинизированные гипербазиты; 12 -раннекембрийские амфиболиты ангурепского метаморфического комплекса; 13 -шалапский полимиктовый субдукционный меланж; 14 -граниты нерасчлененные (ордовикские (?…”

Zircon U-Pb-Hf Isotopes and Whole-Rock Geochemistry of the “Kulumudi Formation” from the Laofengkou Area (West Junggar): Implications of the Construction of a Juvenile Arc in the Junggar–Balkhash Ocean

“…Th complex collage that consists of three major oroclines, including the Kazakh [4], the Mongolian Orocline [5] and the NE China Orocline [6]. Among th mation of the Kazakhstan Orocline has been attributed to the large-angle b Devonian-Carboniferous magmatic arcs during the Late Paleozoic consum Junggar-Balkhash Ocean (the southwestern branch of the Paleo-Asian Ocea These two Devonian-Carboniferous magmatic arcs are difficult to reconstruc ditional study of igneous rocks because of the long-term subduction erosio ever, the arc-derived sedimentary rocks retained on the surface might have formation about the provenances [11,12]. By using whole-rock geochemical and detrital zircon U-Pb-Hf isotope characteristics of these arc-related sedim we can trace the properties of ancient magmatic arcs.…”

Altaids, continental growth and metallogeny

“…[ 8 ] uncover the distinct Andean-type continental arc and oceanic arc-back-arc systems, as well as multi-phase arc accretion/collision in the Permian during the closure of the PAO. Safonova and Perfilova [ 9 ] reconstruct the survived and disappeared fossil intra-oceanic arcs in central and eastern Kazakhstan to manifest that accretionary growth and subduction erosion alternatively functioned at the active margins of the PAO in Paleozoic time. Using the powerful method of comparative orotomy, Kusky and Şengör [ 10 ] compare and contrast the comprehensive geological materials and mechanisms of the Archean Superior and Phanerozoic Altaid orogenic systems, revealing remarkable similarities in accretionary orogenic processes, spatial and temporal scales of structural progression, and formation of continents on Earth over time.…”