التفاصيل البيبلوغرافية
| العنوان: |
Mechanism for the Uplift of Gongga Shan in the Southeastern Tibetan Plateau Constrained by 3D Magnetotelluric Data. |
| المؤلفون: |
Jiang, Feng1,2 (AUTHOR), Chen, Xiaobin1,3 (AUTHOR) cxb@pku.edu.cn, Unsworth, Martyn J.4 (AUTHOR), Cai, Juntao1 (AUTHOR), Han, Bing1 (AUTHOR), Wang, Lifeng1 (AUTHOR), Dong, Zeyi1 (AUTHOR), Cui, Tengfa1 (AUTHOR), Zhan, Yan1 (AUTHOR), Zhao, Guoze1 (AUTHOR), Tang, Ji1 (AUTHOR) |
| المصدر: |
Geophysical Research Letters. 5/16/2022, Vol. 49 Issue 9, p1-8. 8p. |
| مصطلحات موضوعية: |
*OROGENIC belts |
| مصطلحات جغرافية: |
MINYA Konka (China) |
| مستخلص: |
Gongga Shan (GGS) is the highest mountain on the eastern margin of the Tibetan Plateau. However, the mechanism for the uplift of Gongga Shan is still unclear due to a lack of detailed geophysical studies. Inversion of an array of magnetotelluric data at 120 sites produced a 3D resistivity model that revealed that the GGS massif is characterized by a high resistivity upper crust underlain by a westward dipping resistor at middle crustal depths that is interpreted as the underthrust Yangtze Craton (YC). A thin conductive layer is sandwiched between these two zones of high resistivity. This resistivity model is inconsistent with previously published geodynamic models. Based on the new magnetotelluric results, we propose that the uplift of Gongga Shan occurs primarily by underthrusting of the YC. Additional uplift may be due to transpression on a restraining bend of the oblique‐slip Xianshuihe faults. Plain Language Summary: Continent‐continent collisions are an important tectonic process and have controlled the formation of the modern continents. The India‐Asia collision is the best modern example and has produced both a high elevation plateau and the world's highest mountain belts. A range of tectonic processes occurs during these collisions as the crust deforms including extrusion and perhaps crustal flow. Within these collision zones, there are locations of especially rapid uplift that have not been explained with existing geodynamic models. This paper investigates this process through a study of Gongga Shan—a mountain on the eastern edge of the Tibetan Plateau, where uplift continues at a rate of 2–3 mm per year and has formed peaks greater than 7,500 m in elevation. 3D inversion of an array of magnetotelluric data has produced a well‐constrained crustal resistivity model for the GGS area. It reveals that the GGS crust is characterized by four resistivity layers including a westward dipping resistor at depth of 15–30 km overlain by a thin conductive layer. This distinctive structure implies that the basement of the Yangtze Craton is underthrust beneath the Songpan‐Ganzi Terrane, thereby resulting in uplift of the eastern margin of the Tibetan Plateau. Key Points: The middle crust beneath Gongga Shan is characterized by a westward dipping resistor at depth of 15–30 kmGeodynamic models proposed for Gongga Shan are not consistent with the resistivity structureUnderthrusting of the Yangtze Craton beneath the Songpan‐Ganzi Terrane appears to contribute to uplift [ABSTRACT FROM AUTHOR] |
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