Adakite-like granitoids of Songkultau:A relic of juvenile Cambrian arc in Kyrgyz Tien Shan

作     者：D.Konopelko R.Seltmann A.Dolgopolova I.Safonova S.Glorie J.De Grave M.Sun D.Konopelko;R.Seltmann;A.Dolgopolova;I.Safonova;S.Glorie;J.De Grave;M.Sung

作者机构：St.Petersburg State University7/9 University EmbankmentSt.Petersburg199034Russia Novosibirsk State University1 Pirogova St.Novosibirsk630090Russia Natural History MuseumCentre for Russian and Central EurAsian Mineral Studies(CERCAMS)LondonSW75BDUK Sobolev Institute of Geology and Mineralogy SB RASKoptyuga Ave.3Novosibirsk630090Russia Department of Earth SciencesSchool of Physical SciencesThe University of AdelaideSA5005Australia Department of GeologyGhent UniversityKrijgslaan 281/S8B-9000GhentBelgium Department of Earth SciencesThe University of Hong KongPokfulam RoadHong KongChina 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2021年第12卷第1期

页      面：147-160页

核心收录：

学科分类：070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：supported by the Ministry of Education and Science of the Russian Federation(Project No 14.Y26.31.0018-I.S. D.K.) 

主　　题：Northern Tien Shan(Tianshan) Terskey suture Adakite Cambrian juvenile arc 

摘      要：The early Paleozoic Terskey Suture zone,located in the southern part of the Northern Tien Shan domain in Kyrgyzstan,comprises tectonic slivers of dismembered ophiolites and associated primitive volcanics and deepmarine *** the Lake Songkul area,early-middle Cambrian pillow basalts are crosscut by the Songkultau intrusion of coarse-grained gneissose quartz diorites and tonalites with geochemical characteristics typical for high-SiO2 adakites(SiO256 wt.%,Al2O315 wt.%,Na2 O3.5 wt.%and high Sr/Y and La/Yb ratios).The Songkultau granitoids have positive initialεNd(+3.8 to+6.4)andεHf(+12.3 to+13.5)values indicating derivation from sources with MORB-like isotopic *** formations,surrounding the Songkultau intrusion,have geochemical affinities varying from ocean floor to island arc *** rock assemblage is interpreted as a relic of an early-middle Cambrian primitive arc where the adakite-like granitoids were derived from partial melting of young and hot subducted oceanic *** age of 505 Ma,obtained for the Songkultau intrusion,shows that hot subduction under the Northern Tien Shan continued until middle *** primitive arc complexes were obducted onto the Northern Tien Shan domain,where the Andean type continental magmatic arc developed in Cambrian and *** of the Andean type arc was accompanied by uplift,erosion and deposition of coarse clastic sediments.A depositional age of ca.470 Ma,obtained for the gravellites in the Lake Songkul area,is in agreement with the timing of deposition for lower Ordovician conglomerates elsewhere in the Northern Tien Shan,and corresponds to the main phase of the Andean type *** Songkultau adakites in association with surrounding ocean floor and island arc formations constitute a relic of a primitive Cambrian arc and represent a juvenile domain of substantial size identified so far within the predominantly crustal-derived terranes of Tien *** a regional scale this primit