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

作　　者：Inna Safonova Alina Perfilova 

机构地区：[1]LabEPOM,Novosibirsk State University,Novosibirsk 630090,Russia [2]Igneous Petrology Lab,Sobolev Institute of Geology and Mineralogy,Novosibirsk 630090,Russia [3]Paleovolcanism and Geodynamics Lab,Zavaritskiy Institute of Geology and Geochemistry,Yekaterinburg 620016,Russia [4]Faculty of Geosciences and Environmental Engineering,South-West Jiaotong University,Chengdu 610031,China

出　　处：《National Science Review》2023年第2期44-63,共20页国家科学评论（英文版）

基　　金：supported by the Russian Science Foundation(Project#21-77-20022 for U-Pb ages,petrography,geodynamic implications and paper preparation);the Ministry of Science and Education of Russia(Projects#0330-2019-0003 for geochemistry and AAAA-A19-119072990020-6 for isotopes)。

摘　　要：This paper reviews published and presents new data on U-Pb detrital zircon ages,and petrographic,geochemical and isotope(Sm-Nd,Lu-Hf)compositions obtained from greywacke sandstones of Kazakhstan in order to reconstruct fossil intra-oceanic arcs that once existed at Pacific-type convergent margins of the Paleo-Asian Ocean(PAO)in Paleozoic time.We focus on orogenic belts of central Kazakhstan(Itmurundy and Tekturmas)and eastern Kazakhstan(Zharma and Char)in the western Central Asian Orogenic belt.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 make conclusions about the ages and formation settings of their igneous protoliths and define maximum deposition ages.Finally,we discuss the role of serpentinite melanges 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 melanges reconstruct middle-late-Cambrian,Ordovician,late-D evonian 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-D evonian 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

关 键 词：Central Asian Orogenic belt Paleo-Asian Ocean PALEOZOIC subduction erosion greywacke sandstones serpentinite melange 

分 类 号：P736.22[天文地球—海洋地质]