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yexuqing木虫之王 (文学泰斗)
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estern Pacific double subduction drives Gulf of California rifting
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estern Pacific double subduction drives Gulf of California rifting 西太平洋双俯冲作用驱动加利福尼亚湾裂谷形成 ▲ 作者：GUIDO M. GIANNI, XIANG HE, THORSTEN W. BECKER AND CLAUDIO FACCENNA ▲ 链接： https://www.science.org/doi/10.1126/science.aef5187 ▲ 摘要： 大陆裂谷作用反映了构造力与岩石圈强度的平衡，而裂陷机制尚无定论。约600—800万年前加利福尼亚湾斜向裂谷带（GOCOR）的快速裂谷形成是重要实例，其成因可能为岩石圈响应外部运动学条件，或是长期伸展过程加剧，两种模式的动力学机制均尚不明确。 研究组发现，GOCOR快速裂谷事件与西太平洋双向俯冲的起始同步。三维地球动力学模型表明，这种俯冲重组可沿太平洋板块传递5—15兆帕左右的伸展应力，对GOCOR与圣安德烈斯断层南段施加载荷。 俯冲重组或许是触发经历前期改造的岩石圈快速形成GOCOR裂谷的缺失驱动因素，也可能是其他裂谷事件背后被忽略的构造动力。 ▲ Abstract： Continental rifting reflects the balance between tectonic forces and lithospheric strength, yet the mechanisms of breakup remain debated. Rapid rifting of the Gulf of California oblique rift (GOCOR) ~6 million to 8 million years ago is a key example; it may have resulted from the lithosphere responding to external kinematics or acceleration of long-lived extension. The dynamics of either scenario remain incompletely understood. In this study, we highlight that the rapid rifting of the GOCOR coincides with the initiation of Western Pacific double subduction. Using three-dimensional geodynamic models, we show that such subduction reorganization can transmit extensional stresses of ~5 to 15 megapascals across the Pacific plate, loading the GOCOR and the southern San Andreas fault. Subduction reorganization may represent the missing driver for the initiation of rapid GOCOR rifting within a preconditioned lithosphere and may be an overlooked tectonic force behind other rifting events. |
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