基于俯冲倾角的马里亚纳海沟挠曲模拟

彭祎辉; 赵俐红; 凌子龙; 李沐洁; ENNShinn Hway

doi:10.16028/j.1009-2722.2021.213

基于俯冲倾角的马里亚纳海沟挠曲模拟

1.
山东科技大学，青岛 266590

2.
青岛海洋科学与技术试点国家实验室，青岛 266237

基金项目: 国家自然科学基金面上项目“北冰洋美亚海盆岩石圈的挠曲形变特征”（41676039）

详细信息

作者简介: 彭祎辉（1997—），男，在读硕士，主要从事构造动力学方面的研究工作. E-mail：1127665459@qq.com

通讯作者: 赵俐红（1976—），女，博士，副教授，主要从事海洋地球物理方面的研究工作. E-mail：zhaolih@sina.com

中图分类号: P313

收稿日期: 2021-08-13

录用日期: 2022-03-10

刊出日期: 2022-05-28

Deflection simulation of the Mariana Trench based on subduction dip angle

1.
Shandong University of Science and Technology, Qingdao 266590, China

2.
Pilot National Laboratory for Marine Science and Technology(Qingdao), Qingdao 266237, China

More Information

Corresponding author: ZHAO Lihong, zhaolih@sina.com

Received Date: 13 August 2021

Accepted Date: 10 March 2022

Publish Date: 28 May 2022

摘要

摘要:
马里亚纳海沟是西太平洋“沟-弧-盆”构造体系的重要区域，对马里亚纳海沟特征的研究有助于了解海沟各部分间的形成演化差异。基于研究区的沉积物与水深数据，计算了海沟的初始俯冲倾角（β₀）与轴线的挠曲（w₀），模拟了马里亚纳海沟岩石圈的挠曲，得到了马里亚纳海沟各段的岩石圈有效弹性厚度(Te)。模拟结果显示，马里亚纳海沟的挠曲位置约在40～125 km，挠曲幅度w_b约为60～840 m，有效弹性厚度约为5～40 km，初始俯冲倾角β₀约为0.5°～5°，轴线的挠曲w₀约为1.3～4.7 km，整体变化幅度较大；海沟中段的有效弹性厚度最高，南段的有效弹性厚度相对北段略高；海沟中段被大量不同规模的海山侵入，其挠曲幅度、有效弹性厚度、初始俯冲倾角与轴线的挠曲变化幅度都非常大；海沟南段的轴线挠曲很大，明显高于北段与中段，可能与Caroline洋脊的俯冲作用与Caroline热点的影响有关；俯冲初始倾角与有效弹性厚度、挠曲位置、轴线挠曲没有明显的相关关系。
- 初始俯冲倾角 /
- 挠曲 /
- 有效弹性厚度 /
- 马里亚纳海沟
Abstract:
The Mariana Trench is an important area in the evolution of the trench arc basin tectonic system in the Western Pacific Ocean. The study of the characteristics of the Mariana Trench is helpful to understand the differences in the formation and evolution of the trench parts. Based on the sediment and water depth data in the study area, the initial subduction dip angle (β₀) and the axis flexion (w₀) of the trench were calculated, the lithospheric flexion of the Mariana Trench was simulated, and the lithospheric effective elastic thickness (Te) of the Mariana Trench was obtained. The results show that the flexural position of the Mariana Trench is about 40～125 km, the flexural amplitude w_b is about 60～840 m, the effective elastic thickness is about 5～40 km, the initial subduction Angle β₀ is about 0.5°～5°, and the flexural w₀ of the axis is about 1.3～4.7 km. The effective elastic thickness of the middle trench is the highest, and the effective elastic thickness of the northern trench is slightly higher than that of the southern trench. The middle part of the trench is invaded by a large number of seamounts of different sizes, and the range of deflection, effective elastic thickness, initial subduction dip angle and deflection of axis are very large. The axial flexure of the southern segment of the trench is much higher than that of the northern segment and the middle segment, which may be related to the effect of the subduction of Caroline ridge and Caroline hot spot. There is no obvious correlation between the initial subduction dip angle and effective elastic thickness, deflection position and axis deflection.
- initial subduction dip angle /
- flexure /
- effective elastic thickness /
- Mariana Trench

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图 1 洋壳挠曲模型与挠曲计算模型^[25]

Figure 1.

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图 2 马里亚纳海沟的区域位置和水深地形图

Figure 2.

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图 3 马里亚纳海沟各条剖面的实际地形与模拟地形图

Figure 3.

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图 4 沿马里亚纳海沟走向（自北向南）的挠曲参数变化

Figure 4.

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表 1 计算所用参数

Table 1. Parameters used in calculation

参数	定义	数值
	地幔密度，kg/m³	3 300
	海水密度，kg/m³	1 030
g	重力加速度，m/s²	9.81
E	杨氏模量，Pa	7×10¹⁰
ν	泊松比	0.25

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表 2 马里亚纳海沟岩石圈弹性薄板模拟结果

Table 2. Simulation results of lithospheric elastic thin plate in Mariana Trench

	剖面	有效弹性厚度 /km	海沟轴挠曲w₀ /km	初始俯冲倾角β₀/（°）	挠曲幅度w_b /m	挠曲位置/km	RMS/km
北段	1	13	−1.672	2.5	116	62	0.125
	2	14	−1.679	1.5	85	81	0.078
	3	20	−1.656	1	81	109	0.063
中段	4	19	−1.337	0.5	60	114	0.182
	5	24	−1.945	1	94	125	0.373
	6	31	−1.845	3.5	604	45	0.368
	7	30	−1.986	4	696	42	0.203
	8	15	−3.264	4.5	233	68	0.412
	9	37	−3.566	5	839	64	0.297
	10	5	−3.620	0.5	156	46	0.396
南段	11	16	−4.000	2.5	189	95	0.135
	12	22	−4.449	3	231	111	0.153
	13	18	−4.671	4	280	100	0.131

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