| 西太平洋雅浦海沟地幔演化与岩浆作用研究进展 |
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| 引用本文： | 田原,陈灵,唐立梅,高鹏,方银霞.西太平洋雅浦海沟地幔演化与岩浆作用研究进展[J].地球科学,2021,46(3):840-852. |
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| 作者姓名： | 田原 陈灵 唐立梅 高鹏 方银霞 |
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| 作者单位： | 1.自然资源部海底科学重点实验室, 自然资源部第二海洋研究所, 浙江杭州 310012 |
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| 基金项目： | 中央级公益性科研院所基本科研业务费专项资金项目;国家重点研发计划项目;国家自然科学基金项目 |
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| 摘 要： | 俯冲带地幔演化与岩浆作用是地球各固体圈层之间发生物质和能量交换的重要地质过程.西太平洋雅浦海沟因其极短的沟-弧距离和洋脊碰撞等独特的地质构造特征成为研究复杂条件下俯冲带演化的理想场所.为了探究雅浦海沟地幔演化与岩浆作用，本文将前人对雅浦海沟火成岩的研究数据进行整合，分析了雅浦海沟火成岩的成因，并根据火成岩形成的制约条件，对卡罗琳板块俯冲到菲律宾海板块的地幔演化与岩浆作用过程进行了讨论.结果显示雅浦海沟火成岩均具有与俯冲相关火成岩的典型特征.橄榄岩地球化学特征指示雅浦海沟地幔熔融程度为20%~25%，地幔在部分熔融过程中受到了流体与熔体的双重交代作用.Re-Os同位素特征指示雅浦海沟地幔中存在约1.16 Ga非常古老的残余地幔，表明地幔可能经历过多期熔融事件，从而导致雅浦海沟地幔非常亏损.雅浦岛弧成因至今仍存争议，主要包括:(1)现今雅浦岛弧为帕里希维拉海盆洋壳的一部分，在中新世因卡罗琳洋脊的碰撞导致帕里希维拉海盆洋壳逆冲到原雅浦岛弧之上.(2)雅浦岛弧在不同构造时期经历过多期岛弧岩浆作用，包括俯冲初始阶段(~52 Ma)的弧前玄武岩、俯冲开始后的岛弧玄武岩(~25 Ma)、与卡罗琳洋脊碰撞(21 Ma)后的岛弧拉斑玄武岩(7~11 Ma).其中7~11 Ma的岛弧拉斑玄武岩指示雅浦岛弧岩浆活动并未因卡罗琳洋脊的碰撞完全停止，很有可能在晚中新世短暂恢复活动.
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| 关 键 词： | 雅浦海沟 俯冲带 火成岩 地幔演化 岩浆作用 海洋地质 |
| 收稿时间： | 2020-10-30 |
Research Progress on Mantle Evolution and Magmatism in the Yap Trench,Western Pacific |
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| Tian Yuan,Chen Ling,Tang Limei,Gao Peng,Fang Yinxia.Research Progress on Mantle Evolution and Magmatism in the Yap Trench,Western Pacific[J].Earth Science-Journal of China University of Geosciences,2021,46(3):840-852. |
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| Authors: | Tian Yuan Chen Ling Tang Limei Gao Peng Fang Yinxia |
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| Abstract: | Mantle evolution and magmatism in subduction zone are important geological processes in which circulation of materials and energy takes place among the solid layers of the earth. the Yap trench in the western Pacific ocean is an ideal place to study the evolution of subduction zone under complex conditions because of its unique geological structural characteristics such as extremely short trench-arc distance and ocean ridge-trench collision. In order to explore the mantle evolution and magmatism of the Yap trench, this paper analyzes the genesis of the igneous rocks of the Yap trench by integrating the previous research data on the igneous rocks of the Yap trench. According to the formation conditions of the igneous rocks, the mantle evolution and magmatism during the subduction of the Caroline Plate to the Philippine Sea Plate are discussed. The results show that igneous rocks of the Yap trench have the typical characteristics of subduction-related igneous rocks. The geochemical characteristics of peridotite indicate that the melting degree of mantle in Yap trench is 20%-25%, and the mantle is subjected to metasomatism of fluid and melt during the process of partial melting.The Re-Os isotope characteristics indicate that there is an ancient residual mantle with a Re depleted age of 1.16 Ga in the mantle of the Yap trench, indicating that the mantle may have experienced multi-stage melting events, resulting in a ultra-depleted mantle in the Yap trench. The origin of the Yap arc is still controversial up to now, mainly including: (1) The Yap arc is a part of the ocean crust of the Parece Vela basin, which was thrusting above the original Yap Arc in the Miocene due to the collision of the Caroline ridge. (2) Yap Arc experienced several stages of island arc magmatism in different tectonic periods, including forearc basalts at the initial stage of subduction (~52 Ma), island arc basalts after subduction (~25 Ma), and island arc basalts (7-11 Ma) after collision with the Caroline ridge (21 Ma). The 7-11 Ma island arc basalts indicate that the island arc magmatism in the Yap trench has not completely stopped due to the collision of the Caroline ridge and is likely rejuvenated in the Late Miocene. |
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