北山造山带马鬃山增生楔时空演化历史:来自野外精细解剖、碎屑锆石年代学和岩石地球化学的约束  

The spatiotemporal evolution of the Mazongshan accretionary wedge in the Besihan Orogenic Belt: Constraints from fine field anatomy, detrital U-Pb dating and petrogeochemistry

作　　者：王嘉轩 王盛栋 张克信[3] 宋博文[3] 易先奎 罗清发 汤君阳 陈峰 WANG JiaXuan;WANG ShengDong;ZHANG KeXin;SONG BoWen;YI XianKui;LUO QingFa;TANG JunYang;CHEN Feng(School of Geography and Environment,Jiangxi Normal University,Nanchang 330022,China;Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang 065000,China;Institute of Geological Survey,China University of Geosciences,Wuhan 430074,China;Bureau of Geology of Jiangxi Province,Nanchang 330046,China;Experimental Testing Team,Jiangxi Geological Bureau,Nanchang 330002,China;No.270 Research Institute of Nuclear Industry,Nanchang 330200,China)

机构地区：[1]江西师范大学地理与环境学院,南昌330022 [2]中国地质科学院地球物理地球化学勘查研究所,廊坊065000 [3]中国地质大学地质调查研究院,武汉430074 [4]江西省地质局,南昌330046 [5]江西省地质局实验测试大队,南昌330002 [6]核工业二七〇研究所,南昌330200

出　　处：《岩石学报》2024年第4期1102-1122,共21页Acta Petrologica Sinica

基　　金：中国地质调查局地质调查项目(DD20221645);国家自然科学基金项目(42302258);江西省教育厅科研项目(GJJ210327)联合资助。

摘　　要：北山造山带围限于华北克拉通、西伯利亚克拉通和塔里木克拉通之间,是中亚造山带南缘的重要组成部分,学界对其构造-地层区划和地质演化历史长期存在着不同认识。其中贾不泉口子地区的马鬃山增生楔是研究北山地区构造演化的天然载体,本文针对该增生楔的不同地质体开展了详细的识别和解剖,共识别出蛇绿混杂岩岩片、洋岛-海山岩片、洋内弧岩片、深海-半深海硅质岩岩片、活动陆缘-海沟浊积岩岩片和陆缘增生弧岩片等多种岩片类型。在马鬃山增生楔活动陆缘-海沟浊积岩岩片中的两件凝灰质粉砂岩样品(P3-57、P3-110)和一件含砾岩屑砂岩样品(P3-82)获得最大沉积年龄分别为410Ma、430Ma和286Ma。本研究对北山地区古生代的构造古地理格局演变具有重要的约束作用,具体表现为:(1)贾不泉口子地区的马鬃山增生楔岩石组合、变质变形程度与年代学研究存在一定差异,应该对不同类型岩片予以解构分析,还原不同类型岩片的构造古地理背景;(2)贾不泉口子地区的马鬃山增生楔中的3件基质样品的碎屑锆石年龄谱表现出~2.5Ga、~1.5Ga、~0.9Ga、~450Ma、~430Ma、~410Ma、~350Ma和~288Ma的多峰值频谱特征,分别记录了北山地区的变质结晶基底、哥伦比亚和罗迪尼亚超大陆的聚合-裂解事件、活动大陆边缘多期次构造-岩浆事件、残留洋盆以及同碰撞造山快速携入马鬃山增生楔;(3)北山造山带的碎屑锆石年龄频谱占比分布规律存在明显的南北差异,表明马鬃山增生楔的物源区整体上由前寒武纪时期缝合带北侧提供转向由二叠纪时期缝合带南侧提供。The Beishan Orogen, located between the Siberia and North China-Tarim cratons, is an important part of the southern margin of the Central Asian Orogenic Belt. There have been different opinions on its tectonic stratigraphic division and evolution for a long time. The Mazongshan accretionary complex in the Jiabuquankouzi area is a natural research object to disclose the tectonic evolution of the Beishan Orogen. In this study, different geological bodies including ophiolites, oceanic island-seamounts, intra-oceanic arc, bathyal-abbysal cherts, active continental-trench turbidites and continental arc within this complex were recognized and analyzed. Furthermore, two tuffaceous siltstone samples (P3-57 and P3-110) from the turbidites and one pebbly litharenite sample (P3-82) yielded maximum depositional ages of 410Ma, 430Ma and 286Ma, respectively, which can provide important constraints on the paleogeographic evolution of the Beishan area in the Paleozoic. From the above studies, three points of views can be drawn as follows: (1) The rock assemblages, metamorphic degree and geochronology of different tectonic units have great difference, so these tectonic units should be analyzed individually to ascertain their paleogeographic environments. (2) The detrital zircon age spectra of three samples from the matrix of the Mazongshan accretionary complex in the Jiabuquankouzi area display multiple age peaks at ~2.5Ga, ~1.5Ga, ~0.9Ga, ~450Ma, ~430Ma, ~410Ma, ~350Ma, ~288Ma, respectively, which represent their sources from the metamorphic crystalline basement of the Beishan area, the assemblages and break-ups of the Columbia and Rodinia supercontinents, the multiple tectonic-magmatic events in the active continental margin, the remnant oceanic basin and syn-collisional orogen that were carried into the accretionary wedge rapidly. (3)The detrital zircon age spectra of the southern and northern components of the Beishan orogen were largely distinctive from each other, indicating that provenances of the Mazongshan accretionary w

关 键 词：洋板块地质学 增生楔 碎屑锆石年龄 北山造山带 岩相古地理 

分 类 号：P588.212[天文地球—岩石学] P597.3[天文地球—地质学]