GEOROC(Geochemistry of Rocks of the Ocean-sand Continents)是大陆和海洋岩石的地球化学数据库,利用该数据库着重研究了全球新生代汇聚边缘安山岩和玄武岩、裂谷安山岩和玄武岩、洋岛安山岩和玄武岩、埃达克岩等岩浆岩的时空分布特征.结果表明,全球岩浆活动或在中新世开始活跃,或在中新世达到巅峰状态.形成于不同构造环境的岩浆岩具有不同的地质意义:汇聚边缘岩浆岩发育,暗示板块俯冲作用强烈;裂谷岩浆岩大量喷发,表示发育与板块扩张有关的岩浆活动;洋岛岩浆岩迅速增加,指示下地幔异常活跃;埃达克岩广泛分布,表明许多地方受到构造挤压作用,导致地壳加厚.由此推测,全球在中新世可能发生了一次重大的、全球性的岩浆事件.除此之外,全球中新世还发生了一系列重要事件,如青藏高原的隆升及黄土高原的形成、安第斯的抬升、地中海的干涸、全球荒漠化以及西太平洋边缘海盆的发育等.岩浆活动与构造运动通常是相伴而生的,二者间的相互作用改变了古地理、古气候、古环境.中新世剧烈的岩浆活动与构造活动相互作用可能导致地壳加厚或隆起,形成的山脉、高原改变了原有的地形地貌,影响了大气环流,从而改变了地表环境.因此,研究中新世岩浆-构造-气候-环境之间的相互关系,可能是目前和未来一个需要地学工作者长期探索的课题.此外,随着大数据技术的不断发展,科学研究也逐渐步入大数据时代.从全体数据出发,探讨数据之间的关联关系,或许为今后的科研工作提供了一个新的思路.
The GEOROC (Geochemistry of Rocks of the Ocean-sand Continents) database is a comprehensive global petrological database and it is constantly updated and available online to users around the world. Based on this database, we analyze the age data of the global Cenozoic igneous rocks including convergent margin andesite and basalt, continental rift andesite and basalt, ocean island andesite and basalt, adakite, and so on. Statistical analysis reveals that the global magmatism either became active in the Miocene or peaked in the Miocene. Magmatic rocks formed in different tectonic settings represent different geological effects: convergent margin magmatic rock suggests the speed up of subduction; the huge eruption of rift andesite and basalt indicates the occurrence of plate extension; the sharp increase of ocean island andesite and basalt indicates an abnormally active lower mantle, which brings materials from the lower mantle into the crust; a large scale of medium-acid magmatic rock represents the lower crust at high temperature and the asthenosphere mantle strongly upwelling, which leads to the crust intensely reforming; adakite is usually related to strongly tectonic pressing and results in crustal thickening in these areas. In addition, there was a series of significant events in the Miocene. For instance, the Tibetan Plateau rapidly uplifted in the middle Miocene, leading to the formation of the Loess Plateau; the Andean Mountains rose abruptly probably during 8-3 Ma; Tethys dried up from 20-5 Ma, which may have been a cause of the global desertification; the development of the western Pacific marginal sea basins mainly occurred during the late Oligocene to early Miocene. We tried to explain the connection among all of these events as follows. Generally, magmatism usually goes with tectonic activities, and their interaction may change the paleogeography, paleoclimate, and paleoenvironment. The accelerated motion of the Pacific Plate in the Miocene could have thickened or raised the crust, resulting in