摘要
摘要20世纪70-80年代，以Pearce为代表的一批科学家先后提出了玄武岩和花岗岩的构造环境判别图，将构造环境与岩石地球化学特征有机地结合起来，为岩浆岩大地构造环境研究开辟了新途径。但学术界对全球广布的安山岩构造环境及相关地球化学特征问题的讨论则相对不足。本文利用GEOROC和PetDB两个数据库对全球新生代安山岩进行数据挖掘，讨论了它们的地球化学特征及形成环境。初步将全球新生代安山岩归属为12个形成构造环境，其中67．71％产出于岛弧、陆缘弧等汇聚板块边缘环境，其余安山岩则形成于大陆板内、大陆溢流、洋岛、大陆裂谷、洋中脊等构造环境。研究表明，常用的玄武岩微量元素判别图以及LILE／HFSE玄武岩判别图均在一定程度上可用于安山岩成因及环境判别，暗示安山岩地球化学成分也可用于构造环境的判定。采用大数据思维，探索洋岛安山岩（OIA）和岛弧安山岩（IAA）中地球化学元素的关联关系，从获得的近20000个OIA—IAA判别图中选出lg（Cs／Ta）-lg（Cu／Ta）、lg（CaO／Nb）-lg（Cs／Zr）和lg（Cu／Ta）-lg（Co／Nb）等6个图解，能有效限定它们的构造环境，为安山岩成因及形成环境研究提供了新的思路。这些初步成果说明科学大数据的研究方法可成为岩浆岩构造环境及地球化学研究中的重要有效手段。
A set of discrimination diagrams of the tectonic setting interpretation for the granitoids and basahs had been proposed by a group of scientists headed by Prof. Pearce from 1970 to 1980 in 20th century, which created a method to recognize tectonic environment of igneous rocks. In contrast, previous researches for the andesite tectonic settings and its geochemical characteristics were limited. Based on the GEOROC and PetDB databases, this paper mined the Cenozoic data of the global andesite, and discussed their geochemistry characteristics and tectonic settings. 12 different tectonic settings of Cenozoic andesite can be recognized based on the databases preliminarily. The results demonstrate that 67.71% of global Cenozoic andesite was formed at convergent margin like island arc or continental arc. In addition, andesite can also be found in other tectonic settings such as continental intraplate, continental flood, oceanic island, rift and mid-oceanic ridge. We found that both commonly used trace elements discrimination diagrams and LILE/HFSE diagrams for the tectonic settings of the basahs were suitable for andesite to discriminate the tectonic settings to a certain degree. This result illustrated that the geochemistry characteristics of andesite can also discriminate its different tectonic settings. Using big data mind, this paper explored the incidence relation between oceanic island andesites （OIA） and island arc andesites （IAA）. As result, nearly 20 000 OIA-IAA discrimination diagrams came out and after all six of them with good discrimination power were picked up, including lg（ Cs/Ta）-lg（Cu/Ta）, lg（ CaO/Nb）-lg（Cs/Zr）, lg（Cu/Ta）-lg（ Co/ Nb）, etc. It opens up a new way for studying the genesis and geodynamic setting of andesite. The preliminary achievement in this paper reveals that scientific big data could be an important way and method for studying the tectonic settings and geochemical characteristics of igneous rocks.
出处
《地质科学》
CAS
CSCD
北大核心
2017年第3期649-667,共19页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
大陆动力学国家重点实验室自主研究课题和创新团队发展计划项目（编号：IRT1281）资助.
关键词
大数据
安山岩
构造环境
判别分析
新生代
Big data, Andesite, Tectonic settings, Discrimination analysis, Cenozoic
