首页|南海新生代岩浆活动的地球化学特征及其构造意义

南海新生代岩浆活动的地球化学特征及其构造意义

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  • 国家科技期刊平台
  • NETL
  • NSTL
  • 万方数据
  • 维普
基于已发表的和可利用的岩石学及地球化学数据,评述了南海地区新生代(特别是新生代海底扩张停止(17或15.5 Ma)以来)岩浆活动的地球化学特征及其成因,并讨论了其深部地球动力学背景及其对南海形成演化的构造意义.南海新生代早期(60～43 Ma或32 Ma)的岩浆活动呈现双峰式特点,主要出现在南海北缘一系列古近纪盆地内.晚渐新世-中中新世(32～17或15.5 Ma)的岩浆活动主要出现在南海盆扩张中心处,与此同时,南海洋盆之外的地区却处于一个"岩浆活动宁静期".扩张期后(17或15.5 Ma以来)的岩浆活动影响着南海及周缘地区的广泛地区(包括南海北缘珠江口盆地、北部湾、中南半岛以及南海盆本身),但岩浆量不大,其中,17～8 Ma的岩浆活动性质主要呈现拉斑玄武质系列,而8 Ma以来主要为碱性玄武岩系列.南海北缘早期岩浆活动性质反映其处于一个伸展的构造背景,可以很好地响应印度-亚洲碰撞的远场(far-field)效应,可能与地幔柱有关.扩张期后的岩浆活动主要与海南地幔柱有关.此外,在板块构造的框架下,海南地幔柱对南海北缘的伸展裂解及南海新生代海底扩张也扮演了一个重要的次级角色,类似于冈瓦纳大陆裂解时地幔柱的作用.本文最后指出,南海遗迹扩张中心处岩浆活动与东太平洋海隆(EPR)洋脊旁遗迹扩张中心处的岩浆作用类似,可能是一种新的岩浆活动类型,其地球动力学背景尚不清楚;对南海遗迹扩张中心处岩浆活动的研究,将是解决南海构造演化的关键科学问题之一.
GEOCHEMISTRY OF CENOZOIC MAGMATISM IN THE SOUTH CHINA SEA AND ITS TECTONIC IMPLICATIONS
Upon the review of the published geochonological,petrological and geochemical data of Cenozoic igneous rocks from the SCS, this paper studied the genesis and geochemical characteristics of the rocks, as well as their deep geodynamics and tectonic implications. Data show that there existed a bimodal volcanism in the northern margin of the SCS in earlier times (60～43 Ma or 32 Ma) ,followed by a relatively silent stage during the Cenozoic seafloor spreading (32～17 or 15.5 Ma),except for the central basin. And a large area of post-spreading volcanism (tholeiitic series for 17～8 Ma,alkali series since 8 Ma) affected the SCS and its adjacent areas (e.g. ,Pearl River Mouth Basin, Beibu gulf,Indochina block and the South China Sea basin). The earlier volcanism occurred in an extensional geodynamic setting resulted from the collision between Indian plate and Eurasian plate as a far-field effect,and the post-spreading volcanism may be related to the Hainan mantle plume. The Hainan mantle plume played a subtle but important role in the extensional process of the northern margin and the seafloor spreading of the SCS. Finally, this study proposed that the igneous activities at fossil spreading centers in the SCS are similar to those in the East Pacific Rise and might be a new type of volcanism. The timing and geodynamic setting of the volcanism remain unclear. Why the extinct spreading centers continue to erupt after cessation of spreading is a brand new scientific problem. The further study of the igneous activity along the fossil spreading centers in the SCS is critical to the understanding of the tectonic evolution of the SCS.

Cenozoic magmatismtectonic evolutionHainan mantle plumefossil spreading centerSouth China Sea

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海洋沉积与环境地质国家海洋局重点实验室,国家海洋局第一海洋研究所,青岛266061

新生代岩浆活动 构造演化 海南地幔柱 遗迹扩张中心 南海

国家重点基础研究发展规划(973计划)中国博士后科学基金山东省博士后创新项目专项资金国家海洋局第一海洋研究所基本科研业务费专项资金山东省泰山学者建设工程专项项目

2008FY220300200904501348200802007GY02-2008G38

2011

10.3724/SP.J.1140.2011.02059

海洋地质与第四纪地质
青岛海洋地质研究所

海洋地质与第四纪地质

CSTPCDCSCD北大核心
影响因子：0.614
ISSN：0256-1492
年,卷(期)：2011.31(2)
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