Effects of Plate Velocity Slowdown on Altering Continental Collision Patterns and Crustal-Lithospheric Deformation During the Collision Process

Mengxue Liu,Dinghui Yang,Pengpeng Huangfu

doi:10.3389/feart.2022.814710

Mengxue Liu, Dinghui Yang + Show 1 more

Open Access

https://doi.org/10.3389/feart.2022.814710

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Abstract

Continental collision zones are widely distributed across the earth’s surface with diverse types of tectonic processes. Even the same collision zone shows significant lateral tectonic variations along its strike. In this study, we systematically investigated how plate velocity slowdown after the closure of the ocean influences the continental collision evolution, as well as the effects of kinematic characteristics and continental rheology on varying the continental collision modes in a plate velocity slowdown model. From the comparison between the constant plate velocity system (CVS) and the plate velocity-dropping system (VDS), we can conclude the following: Plate velocity dropping promotes the extension inside the slab by decreasing the movement of the surface plate, whereas slab pull increases as subduction continues. The timing of the subducting slab break-off and the polarity alteration was initiated earlier in the plate velocity drop models than in the constant plate velocity models, and fast convergence may have triggered multiple episodes of slab break-off and caused strong deformation adjacent to the collision zone. Parametric tests of the initial subducting angle, plate convergence velocity, and continental crustal rheological strength in VDS indicated the following: (1) Three end members of the continental lithospheric mantle deformation modes were identified from the VDS; (2) models with a low subducting angle, fast continental convergence velocity, and medium-strength overriding crust were more likely to evolve into a polarity reversed mode, whereas steep-subducting-angle, slow-plate-velocity, weak-overriding-crust models tended toward a two-sided mode; (3) a strong overriding continent is more liable to develop a stable mode; and (4) overriding crustal rheological strength plays a significant role in controlling changes in continental collision modes.

Highlights

Continental collision is an important process for regional tectonic evolution
It has been recognized that dramatic plate velocity slowdown after continental collision following oceanic subduction is a general phenomenon, but little work has been done using numerical modeling to systematically investigate how such a convergence velocity drop influences the spatial–temporal evolution of crustal-lithospheric deformation during continental collision
By varying the continental convergence velocity, the dip angle of the initial weak zone, and retrocontinental crustal rheological strength, we examined how these parameters influence the spatial−temporal evolution of the continental collision process in velocity-dropping system (VDS)

Summary

Introduction

Continental collision is an important process for regional tectonic evolution. It is widely distributed across the earth, ranging from the Mediterranean Sea to southwestern China (Figure 1A) (Li et al, 2011; Handy et al, 2010, 2015; Roda et al, 2010, 2012), significantly affecting the climate, resource reallocation, surface topography construction process, and deep mantle spatial–temporal evolutionVarious Continental Collision Modes (Wang et al, 2014; Li et al, 2015). Complex discrepant tectonic evolution exists among different continental convergence zones (Negredo et al, 2007; Chertova et al, 2014; Spakman et al, 2018), and even the same collision zone shows evident lateral variations of tectonic characters along its strike direction (Chen et al, 2015; Liang et al, 2016); in particular, along the Himalaya orogen, tomographic images have recognized distinct east–west inhomogeneous subducting angles and horizontal slip distances (Figures 1B,C) there. Mechie et al (2011a, 2011b, 2012) adopted receiver function method to identify Moho characters across Tibet Plateau and recognized that Indian lithospheric mantle extends northwards until about the Banggong-Nujiang suture, where it steeply sinks to 350–400 km depth. Alpine orogen exhibits several distinct lithospheric mantle deformation features (Kissling et al, 2006; Roda et al, 2010, 2012; Handy et al, 2015; Zhao et al, 2015); e.g., under the central and eastern Alps, subductions operate in an opposite polarity (Figure 1D, profile CC′), while in the western Alps, the overriding Adriatic lithospheric mantle seemed to delaminate and was dragged down by the subducting European lithosphere (Figure 1E, profile DD’)

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