Some Key Issues in Contemporary Continental Tectonics: An Overview

Plate tectonics theory, grounded on the assumption of nearly rigidity of plate interior, is elucidated as deformation concentrated on the narrowly defined plate boundaries; however, the current flooding datum of space-based geodetic observations have shown that continental deformation is not confined to the nominated plate boundaries, but even expanding to the inland area thousand kilometers far away from which. To understand this diffuse continental deformation is of fundamental importance to modern earth science and geological hazards mitigation. Despite of much advancement of our knowledge on continental deformation in the past few decades, many aspects of it still remain uncertain. Here we will focus on three controversial but interesting topics in the latest literatures on continental tectonics as follows: continental deformation pattern derived mainly from kinematic constraints, the rheology and strength of the continental lithosphere based on the studies on earthquake activities and experiment-based rock mechanism extrapolation, especially contrast between the effective elastic thickness (Te) and seismogenic thickness (Ts). Suffered from the long history of tectonic alternation with accretion, collision and magmatism, the continental lithosphere is characteristiced by remarked heterogeneities in composition, structure and mechanical properties, including some pre-existing tectonic inheritances as the weak zones. In a conclusion, we propose that thermo-rheological heterogeneity in continental lithosphere and the pre-existing tectonic inheritance are the key factors controlling its deformation pattern and rate, under the applied forces derived from the far-field plate boundary, along with the gravitational potential energy within continent due to the existence of density contrast. More attention should be paid on the enhancement of data on kinematics and lithospheric structure from observations of GPS, quaternary fault slip rate, and seismology, respectively; combining these constraints and more realistic rheology with advanced computation geodynamic modeling will no doubt lead to our better understanding on the continental tectonics.