Dynamics of Oceanic Slab Tearing During Transform-Fault Horizontally-Oblique Subduction: Insights From 3D Numerical Modeling
文献类型：期刊论文
| 作者 | Xin, Jie5; Zhang, Huai3,4,5; Orellana-Rovirosa, Felipe2; Li, Zhong-Hai5; Liu, Liang1; Xu, Yi-Gang1; Zhang, Zhen5; Shi, Yaolin5 |
| 刊名 | JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
 |
| 出版日期 | 2023-07-01 |
| 卷号 | 128期号:7页码:23 |
| 关键词 | oceanic slabs vertical tearing horizontally oblique subduction transform-fault offset 3D numerical models Stokes' flow |
| ISSN号 | 2169-9313 |
| DOI | 10.1029/2023JB027041 |
| 英文摘要 | Oceanic-plates vertical tearing is seismically identified in the present-day Earth. This type of plate tearing is frequently reported in horizontally-oblique subduction zones where transform-faulted oceanic plates are subducting (or subducted). However, the mechanisms behind vertical slab tearing are still poorly understood, thus we utilize 3D time-dependent Stokes' flow thermo-mechanical numerical models to further study this problem. We find that (a) the age offset of transform fault and (b) the horizontal obliqueness of subduction fundamentally control the tearing behavior of two generic, materially homogeneous oceanic slabs separated by a low-viscosity zone. The two slabs sequentially bend, which combined with the age-thickness difference between slabs, causes the differential sinking of them. Based on the modeling results, well-developed slabs vertical tearing would happen when the oblique angle of subduction is >= 30 degrees or the age ratio of the secondly bent to firstly bent slab being similar to<0.6. Quantifying the horizontal distance-vector between sinking slabs, we find that subduction at medium-low horizontal-obliqueness angles (<= 40 degrees) of young lithosphere (slabs-average similar to 15 Myr) tends to produce fault-perpendicular tearing. Contrastingly, old-age slabs (average >= 30 Myr) with medium-large obliqueness angles (similar to>20 degrees) tend to produce fault-parallel tearing, related to differential slab-hinge retreat or rollback. Correlations between slabs' (a) computed tearing horizontal-width and (b) scaling-theory forms of their subduction-velocity differences, are reasonable (0.76-0.97). Our numerically predicted scenarios are reasonably consistent with plate-tear imaging results from at least four natural subduction zones. Our modeling also suggests that continual along-trench variation in subduction dip angle may be related to a special case of oblique subduction. Plain Language Summary Oceanic tectonic plates can tear-off through time as they plunge and sink into the Earth's mantle and are especially favored when plates have preexisting fault-weak zones. Two primary conditions promote oceanic tectonic slabs' tearing: (a) Obliqueness of a plate's horizontal velocity with respect to the overriding-plate coastline and trench, leading to the two slabs sequentially bending yet having differences in deformation; (b) Differences in slab-age between two sides of a displaced fault-zone that created an offset in plate age and thickness. To understand these processes, we present 3D numerical models that simulate tectonic evolution and deformations, and we compare model results with analytical studies as well as with natural observations from seismic imaging. Age differences across fault-zones combined with subduction horizontal obliqueness control the generation and development of vertical tearing. Furthermore, two geometrical patterns of vertical tearing are largely consistent with observations. Our findings suggest that along-trench changes in the steep angle between the slab and surface (dip angle) may be related to a special case of oblique subduction. Observing the age contrast across faults and the horizontal obliqueness of plates' motion allows predictions of the tearing pattern, evolution, and local mantle flow. |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:001059657600010 |
| 源URL | [http://ir.gig.ac.cn/handle/344008/74523]  |
| 专题 | 同位素地球化学国家重点实验室 |
| 通讯作者 | Zhang, Huai |
| 作者单位 | 1.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Isotope Geochem, Guangzhou, Peoples R China 2.Southern Univ Sci & Technol, Dept Ocean Sci & Engn, Shenzhen, Peoples R China 3.Southern Marine Sci & Engn Guangdong Lab Zhuhai, Zhuhai, Peoples R China 4.Univ Chinese Acad Sci, Beijing Yanshan Earth Crit Zone Natl Res Stn, Beijing, Peoples R China 5.Univ Chinese Acad Sci, Coll Earth & Planetary Sci, Key Lab Computat Geodynam, Beijing, Peoples R China |
| 推荐引用方式 GB/T 7714 | Xin, Jie,Zhang, Huai,Orellana-Rovirosa, Felipe,et al. Dynamics of Oceanic Slab Tearing During Transform-Fault Horizontally-Oblique Subduction: Insights From 3D Numerical Modeling[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,2023,128(7):23. |
| APA | Xin, Jie.,Zhang, Huai.,Orellana-Rovirosa, Felipe.,Li, Zhong-Hai.,Liu, Liang.,...&Shi, Yaolin.(2023).Dynamics of Oceanic Slab Tearing During Transform-Fault Horizontally-Oblique Subduction: Insights From 3D Numerical Modeling.JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,128(7),23. |
| MLA | Xin, Jie,et al."Dynamics of Oceanic Slab Tearing During Transform-Fault Horizontally-Oblique Subduction: Insights From 3D Numerical Modeling".JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 128.7(2023):23. |
入库方式： OAI收割
来源：广州地球化学研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。