| 地壳放射性生热效应对大陆俯冲过程影响的数值模拟研究 |
| |
| 引用本文： | 宋菁菁,王岳军,范蔚茗,皇甫鹏鹏,周永智.地壳放射性生热效应对大陆俯冲过程影响的数值模拟研究[J].大地构造与成矿学,2018(1):60-72. |
| |
| 作者姓名： | 宋菁菁 王岳军 范蔚茗 皇甫鹏鹏 周永智 |
| |
| 作者单位： | 中山大学 地球科学与工程学院, 广东省地球动力作用与灾害重点实验室, 广东 广州 510275;中国科学院大学, 北京 100049
中山大学 地球科学与工程学院, 广东省地球动力作用与灾害重点实验室, 广东 广州 510275
中国科学院 青藏高原研究所 大陆碰撞与高原隆升重点实验室,北京,100101
中国科学院大学 地球科学学院 计算地球动力学实验室,北京,100049 |
| |
| 基金项目： | 国家自然科学基金项目，973项目，国家重点研发计划项目 |
| |
| 摘 要： | 岩体中的放射性生热是地幔对流和地壳变质作用的关键热源之一,但地壳放射性生热率是如何影响大陆俯冲-碰撞的动力学过程,尤其是大陆碰撞区域的热结构演化,尚未获得共识。本文使用热-力学数值模拟方法对上、下地壳放射性生热率进行系统的模拟实验,以研究其对大陆俯冲动力学演化过程的影响。模型实验表明,由于大陆上地壳富集U、Th和K等主要放射性生热元素,且放射性生热率的变化区间较大(1.0~3.0μW/m~3),导致其对大陆俯冲碰撞动力学演化过程的影响较为显著,主要包括进入俯冲通道内的上地壳体积大小、碰撞区域内地壳熔融范围、俯冲下地壳物质折返的规模和两大陆的耦合程度等四个方面。而大陆下地壳则以中-基性岩为主,相对亏损U、Th、K等主要放射性生热元素,且放射性生热率的变化区域较小(0.2~0.8μW/m~3),致使其对大陆俯冲演化过程的影响相对有限,主要通过控制俯冲下地壳以及大陆板片的粘滞度和流变强度的大小,进而制约大陆俯冲过程下地壳物质折返的规模以及板片倾角的大小。
|
| 关 键 词： | 放射性生热 大陆俯冲 地壳熔融 俯冲地壳折返 板片倾角 radiogenic heat production continental subduction crustal melting burial and exhumation process slab dip angle |
Effects of Crustal Radiogenic Heat Production on Continental Subduction: Insights from Numerical Modelling |
| |
| SONG Jingjing,WANG Yuejun,FAN Weiming,HUANGFU Pengpeng,ZHOU Yongzhi.Effects of Crustal Radiogenic Heat Production on Continental Subduction: Insights from Numerical Modelling[J].Geotectonica et Metallogenia,2018(1):60-72. |
| |
| Authors: | SONG Jingjing WANG Yuejun FAN Weiming HUANGFU Pengpeng ZHOU Yongzhi |
| |
| Abstract: | Radiogenic heat production is a key energy source for convection in the Earth's mantle and for metamorphic reactions in the continental crust. However, its effects on continental subduction remain a poorly resolved aspect of plate tectonics. Based on 2D thermo-mechanical modeling, the sensitivity of model results to radiogenic heat production rates in the continental upper crust and lower crust is thoroughly investigated. The granodioritic upper crust usually concentrates radioactive isotopes (e.g., U, Th and K) with a wide range of radiogenic heat production rate, i.e., roughly from 1.0 μW/m3to 3.0 μW/m3. The radiogenic heat significantly effects the continental subduction evolution including the volume of subducted continental upper crust, the distribution and evolution of crustal melting in the collision zone, exhumation of subducted lower crust along the subduction channel, and coupling of the subducting continent with the overriding continent. In contrast, the mafic lower crust is depleted in radioactive isotopes (e.g., U, Th and K), resulting in a low radiogenic heat production rate (0.2 0.8 μW/m? 3) and relatively limited influences on the geodynamic processes of continual subduction. Specifically, the radiogenic heating of the continental lower crust mainly regulates the viscosity and rheological strength of the continental slab to further affect the degree of the lower crust exhumation and the continental slab dip angle. |
| |
| Keywords: | |
| 本文献已被 CNKI 万方数据 等数据库收录！ |
|
