Numerical model of the supercontinental cycle stages: Integral transfer of the oceanic crust material and mantle viscous shear stresses

Abstract

We compute the transfer of oceanic lithosphere material from the surface of the model to the inner convective mantle at successive stages of the supercontinental cycle, in the time interval from the beginning of convergence of the continents to their complete dispersal. The sequence of stages of a supercontinental cycle (Wilson cycle) is calculated with a two-dimensional numerical model of assembling and dispersing continents driven by mantle flows; in turn, the flows themselves are forming under thermal and mechanical influence of continents. We obtain that during the time of the order of 300 Myr the complete stirring of oceanic lithosphere through whole mantle does not occur. This agrees with current ideas on the circulation of oceanic crust material. Former oceanic crust material appears again at the Earth's surface in the areas of mantle upstreams. The numerical simulation demonstrates that the supercontinental cycle is a factor which intensifies stirring of the material, especially in the region beneath the supercontinent. The reasons are a recurring formation of plumes in that region as well as a global restructuring of mantle flow pattern due to the process of joining and separation of continents. The computations of viscous shear stresses are also carried out in the mantle as a function of spatial coordinates and time. With a simplified model of uniform mantle viscosity, the numerical experiment shows that the typical maximal shear stresses in the major portion of the mantle measure about 5 MPa (50 bar). The typical maximal shear stresses located in the uppermost part of mantle downgoing streams (in a zone that measures roughly 200 × 200 km) are approximately 8 times greater and equal to 40 MPa (400 bar). K e y w o r d s : supercontinental cycle, mass transfer, shear stresses, numerical experiment

Convection Cells With Accumulating Crust: Models of Continent and Mantle Evolution

“…The studies with insulating models of continents have been of gradually increasing complexity. Many of them show or analyze a partial cycle (Bobrov & Trubitsyn, 2008; Butler & Jarvis, 2004; Honda et al., 2000; Korenaga, 2007; Lenardic et al., 2011; Lowman & Gable, 1999; Lowman & Jarvis, 1993, 1996, 1999; Rykov & Trubitsyn, 1996; Trubitsyn & Rykov, 1995; Yoshida, 2019; Zhang et al., 2009, 2018; Zhong et al., 2007) and some have achieved full cycles (Gurnis, 1988; Phillips & Bunge, 2007; Whitehead, 2017). All results indicate the universal nature of continent‐convection interaction, and many quantify the role it plays in the evolution of Earth.…”

“…Subsequent models for continent/convection interaction have become more complex (Bobrov & Baranov, 2018, 2019; Coltice et al., 2007; Grigné et al., 2007, 2007a, 2007b; Guillou & Jaupart, 1995; Lowman & Jarvis, 1993, 1995, 1996, 1999; Lowman & Gable, 1999; Lenardic et al., 2011; Rykov & Trubitsyn, 1996; Trubitsyn & Rykov, 1995; Yoshida et al., 1999; Zhong & Gurnis, 1993). Studies include flow in a sphere ( Phillips & Bunge, 2007; Trubitsyn et al., 2008; Yoshida, 2010a,b, 2013, 2019 ; Zhang et al., 2009, 2018), effects on polar wander (Li & Zhong, 2009; O’Neill et al., 2009) formation of crust (Bobrov & Trubitsyn, 2008; Rozel et al., 2017), and convection's effects on Earth's heat budget when cycles are included (Coltice et al., 2007; Heron & Lowman, 2011, 2014; Lenardic et al., 2000, 2011; Phillips & Coltice, 2010; Rolf et al., 2012; Trubitsyn et al., 2008; Yoshida, 2013). The studies by Heron et al.…”

Modeling of Moving Deformable Continents by Active Tracers: Closing and Opening of Oceans, Recirculation of Oceanic Crust

“…In [Bobrov, Trubitsyn, 2008], the movements and mixing of the submerged oceanic lithosphere material in the mantle and its subsequent rise to the surface were determined in the successive stages of the calculated supercontinental cycle. Simultaneously, the fields of viscous maximum shear stresses and the orientations of their axes were calculated from the obtained fields of mantle material flows.…”