地质学报Issue(8)：1461-1474,14.
扬子克拉通东南缘新元古代陆缘弧型TTG的厘定及其构造意义
Identification and Tectonic Implication of Neoproterozoic Continental Margin-Arc TTG Assemblage in Southeastern Margin of the Yangtze Carton
摘要
Abstract
Along the southeastern margin of the Yangtze Carton expose several Neoproterozoic dioritic-granitic plutonic complexes,which were considered as within-plate plutons intruding along the Jiangshan-Shaoxing suture belt between the Yangtze Carton and Cathaysia Block.This paper introduces petrography, chronology and geochemistry of Luodian intermediate-acid plutonic complex in Jinhua,Zhejiang Province, and ascribed as TTG assemblage that including T1 T2 G1 (tonalite-trondhj emite-granodiorite )and G2 QM (granite-quartz monzonite).They display typical geochemical characters of arc magmas,i.e.,weakly negative Ce anomalies and obvious enrichments in LILE such as Rb,Ba,K,Pb,whereas depletion in HFSE such as Nb,Ta,Ti,P.T1T2G1 ssemblages,showing high Na,low K with high Mg# (41. 5~63. 1) andε Nd (t)(+2 .6~+9 .4 ),may be formed by the partial melting of dehydrated subducted basaltic slab and partly assimilated by mantle wedge.G2 QM assemblages,having similar geochemical features to T1 T2 G1 whereas comparatively higher K2 O content (from 2.75 % to 5.08 %),higher LILE and LREE,and lower Mg# value (27.2~52.3)andε Nd(t)(+1.7~+2.0),implicated the subsequent partial melting of the subducted slab but without obvious assimilation of mantle wedge.Their zircon U-Pb ages of granodiorite(G1 ),trondhjemite(T2 )and granite(G2 )are 841 ±10Ma(SHRIMP),793 ±13Ma(LA-ICP-MS)and 832±44Ma,respectively,indicating these T1T2G1 and G2QM rocks were continental margin arc magmatites formed by continuous subduction of Paleo-Nanhua Ocean slab in Neoproterozoic.Combined with regional geologies and previous studies, it is proposed that, Luodian complex in Jinhua and Huangshan complex in Zhuji as well as Pingshui complex in Shaoxing make up a 200km long, Neoproterozoic (930 ~ 793Ma ) continental margin-arc plutonic complex zone.In other words, the southeastern margin of the Yangtze Carton had not collided and amalgamated with the Cathaysia Block at least until 793 Ma,while coexisting of T1 T2 G1-G2 QM rocks predicate an early-middle subduction of oceanic crust.关键词
陆缘弧型TTG岩石组合/新元古代/金华罗店/钦杭结合带/扬子克拉通东南缘Key words
continental margin-arc TTG/Neoproterozoic/Luodian in Jinhua/Qinzhou-Hangzhou joint belt/southeastern margin of the Yangtze Carton引用本文复制引用
姜杨,赵希林,林寿发,Donald W. DAVIS,邢光福,李龙明,段政..扬子克拉通东南缘新元古代陆缘弧型TTG的厘定及其构造意义[J].地质学报,2014,(8):1461-1474,14.基金项目
国家自然科学基金青年基金（批准号41002024）、国土资源部公益性行业科研专项经费项目（编号200811015）和中国地质调查局华东基础地质调查成果集成与综合研究项目（编号1212011220542）联合资助。 （）
