摘要
本文总结和回顾了过去几年来本研究团队在华南陆块东部(主要是东南沿海地区)开展的火成岩岩石地球化学研究进展,并重点探讨了晚中生代(白垩纪)岩浆作用的深部动力学过程,取得了以下主要认识:①华南晚中生代镁铁质岩浆作用记录了古太平洋板块从俯冲到后撤‒撕裂的深部动力学过程,其地幔源区的富集组分从进俯冲时期的板片上覆沉积物逐渐过渡到后撤‒撕裂阶段的下部镁铁质洋壳;②长英质火山岩的地壳源区从俯冲阶段的低温(700~810℃)含水下地壳转变为后撤‒撕裂阶段的高温(790~860℃)贫水陆壳;③东南沿海地区晚中生代经历了强烈的弧地壳增生和置换作用,形成了具有“等同位素效应”的双峰式侵入杂岩体。我们提出的板片俯冲‒后撤‒撕裂模式同样适用于解释华南陆块东部早中生代构造‒岩浆演化的深部的动力学机制。
In this paper,we review the petrological and geochemical studies of the late Mesozoic igneous rocks in the eastern part of South China(mainly the southeast coastal area)conducted by our group during the past five years,focusing mainly on the geodynamic process of the Cretaceous magmatism.The main advancements include:(1)The late Mesozoic mafic magmatism in South China recorded the geodynamic processes from subduction to rollback and tearing of the paleo-Pacific slab.During these processes,the mantle sources for the mafic magmas were enriched by the subducted sediments of the upper oceanic crust during the advanced subduction and were then metasomatized by the lower oceanic crust in response to the slab retreat and tearing.(2)The crustal sources for felsic volcanic rocks changed from the low-temperature(700-810℃)water-rich crust in the advanced subduction stage to the high-temperature(790-860℃)water-poor continental crust in the rollback-tearing stage.(3)The late Mesozoic crust in the southeast coastal area experienced extensive crustal accretion and subduction-induced replacement,forming the‘equal-isotope’and petrochemically bimodal intrusive complexes.We propose that the slab subduction-rollback-tearing model may also be applicable to the geodynamics of the early Mesozoic tectonic-magmatic evolution in the eastern South China Block.
作者
郭锋
赵亮
张晓兵
吴扬名
张博
张峰
GUO Feng;ZHAO Liang;ZHANG Xiaobing;WU Yangming;ZHANG Bo;ZHANG Feng(State Key Laboratory of Isotope Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;Center of Excellence of Deep Earth Sciences,Guangzhou 510640,Guangdong,China;School of Earth Sciences and Engineering,Sun Yat-sen University,Zhuhai 519082,Guangdong,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2022年第3期416-434,共19页
Geotectonica et Metallogenia
基金
国家自然科学基金项目(U1701641,41525006,42073032,42021002)资助。
