The divergent rifting/spreading centers and the strike-slip transform faults are the essential tectonic units on Earth, the dynamic evolution of which regulates the development of rifting/spreading basins. The propagation of rifting/spreading centers may interact with pre-existing transform faults, but how they interact with each other remains enigmatic. Here we use three-dimensional geodynamical numeric models to systematically simulate the interaction between rifting/spreading propagation and the pre-existing transform faults. Our model results provide the following findings. 1) The pre-existing transform faults affect rifting/spreading propagation promoting the formation of ridge segments with an offset distance, facilitating the process of spreading of the western sea basin and restraining the propagation of the east sea basin. Yet, the evolution of the transform faults is regulated by rifting/spreading propagation, featured by the increase of its length, the change in its width along strike and the presence of lineated magmatism. 2) The initial length and orientation of the pre-existing transform faults largely affect rifting/spreading propagation, i.e., large transform fault length favors the formation of large offset between ridge segments, and oblique transform faults facilitate the formation of overlapped spreading centers. 3) Model results shed new light on the evolution of the South China Sea basin, implying that the observed ridge segments in the east and southwest sub-basins, the difference of the Zhongnan Fault Zone width along strike and the lineated volcanos along the Zhongnan Fault Zone are the results of the interaction between the rifting/spreading propagation and the pre-existing transform fault.
The convergent subduction zones and the divergent spreading ridges are essential tectonic units that are widely distributed in the South China Sea and the surrounding regions, governing the regional tectonic evolution. Subduction-spreading interaction may be present between these two tectonic units, especially when they are located adjacent. Quantitative study of subduction-spreading interaction remains insufficient. Using 2D thermomechanical numeric modeling, we systematically study subduction-spreading interaction with particular attention paid on the influence of lower plate spreading versus upper plate spreading on subduction development. Our modeling results provide the following findings. (1) Intensive interaction is present between the adjacently located spreading center and subduction zone through plate motion and mantle convection, and positive feedback is present between these two units, i.e., spreading promotes subduction and vise verse. (2) The location of spreading center either on the upper or lower plate facilitates the formation of passive and active subduction, respectively, and the offset distance between the two units affects the intensity of subduction-spreading interaction. (3) Subduction-spreading interaction may be widely present in the South China Sea and the surrounding regions, where multiple subduction zones and spreading centers distribute adjacently in the present and evolved episodically in the past.
Abstract Distinct signatures are present in the circum‐Pacific continental margins (e.g., kinematics, magmatism, and basin evolution), possibly influenced by the input of mid‐ocean ridge. It remains enigmatic why the circum‐Pacific continental margins that have experienced trench‐parallel mid‐ocean ridge subduction show diverse geological evolution. Here we present geodynamic modeling results investigating trench‐parallel mid‐ocean ridge subduction and demonstrate two distinct types of model evolution. Type‐Ⅰ model includes a two‐stage steep subduction and is featured by slab detachment preceding the arrival of ridge at the trench. Type‐Ⅱ model is marked by a continuous flat subduction of mid‐ocean ridge with the opening of a slab window beneath intracontinental lithosphere. These two subduction styles produce diverse tectono‐magmatic responses. Our results could explain the magmatic gap and forearc uplift during the Izanagi‐Pacific ridge subduction and the intraplate magmatic flare‐ups and tectonic uplift during the Nazca‐Antarctic ridge subduction, respectively.
This dataset contains the data used in Wu et al. (2022): "Styles of Trench-parallel Mid-ocean Ridge Subduction Affect Cenozoic Geological Evolution in circum-Pacific Continental Margins".
This dataset contains the data used in Wu et al. (2022): "Trench-parallel Mid-ocean Ridge Subduction Affect Cenozoic Geological Evolution in circum-Pacific Continental Margins".
This dataset contains the data used in Wu et al. (2022): "Styles of Trench-parallel Mid-ocean Ridge Subduction Affect Cenozoic Geological Evolution in circum-Pacific Continental Margins".
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