Contemporary crustal movement of southeastern Tibet: Constraints from dense GPS measurements.
Contemporary crustal movement of southeastern Tibet: Constraints from dense GPS measurements.
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DOI：
10.1038/srep45348
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发表时间：
2017-03-28
影响因子：
4.6
通讯作者：
Shen WB
中科院分区：
文献类型：
--
作者：
Pan Y;Shen WB
印度板块与欧亚板块的不断碰撞导致了青藏高原南北向地壳缩短和增厚，但其动力学机制仍存在争议。藏东南地区作为世界上构造活动最活跃的地区之一，一直受到地学界的广泛关注。在此，我们提出了最新的三维GPS速度场约束的现代构造过程，这可能会突出复杂的地壳垂直变形。采用改进的数据处理策略，以提高整个SET的应变模式。区域深部构造动力学过程控制着地壳的隆升和沉降。结果表明，贡嘎山正以1 ~ 1.5mm/a的速率隆升。然而，龙门山构造的地壳异常隆升速率约为8.7mm/年，水平负膨胀速率为40-50 N应变/年，表明龙门山构造是由扬子板块的陆内俯冲作用引起的。鲜水河-小江断裂是一条主要的活动左旋走滑断裂，其走向基本上与最大剪应变率一致。这些观测结果表明，上地壳形变与深部物质的调控和耦合密切相关。
The ongoing collision between the Indian plate and the Eurasian plate brings up N-S crustal shortening and thickening of the Tibet Plateau, but its dynamic mechanisms remain controversial yet. As one of the most tectonically active regions of the world, South-Eastern Tibet (SET) has been greatly paid attention to by many geoscientists. Here we present the latest three-dimensional GPS velocity field to constrain the present-day tectonic process of SET, which may highlight the complex vertical crustal deformation. Improved data processing strategies are adopted to enhance the strain patterns throughout SET. The crustal uplifting and subsidence are dominated by regional deep tectonic dynamic processes. Results show that the Gongga Shan is uplifting with 1–1.5 mm/yr. Nevertheless, an anomalous crustal uplifting of ~8.7 mm/yr and negative horizontal dilation rates of 40–50 nstrain/yr throughout the Longmenshan structure reveal that this structure is caused by the intracontinental subduction of the Yangtze Craton. The Xianshuihe-Xiaojiang fault is a major active sinistral strike-slip fault which strikes essentially and consistently with the maximum shear strain rates. These observations suggest that the upper crustal deformation is closely related with the regulation and coupling of deep material.