Seafloor spreading evolution in response to continental growth

Abstract

The growth of the continental crust has shaped the evolution of the Earth from its interior to its fl uid envelopes. Continents have played a major role in the evolution of global tectonics through their interaction with mantle convection. The feedback between continents and mantle convection has been studied for the past 25 years, but it is only recently that the dynamic infl uence of continents on seafl oor spreading can be explored thanks to progress in convection modeling. In this work, we investigate how continental size impacts seafl oor spreading activity with state-of-the-art three-dimensional spherical convection models. We show that increasing the continental area forces higher production rates of new seafl oor with stronger fl uctuations. As a consequence, the average age of the seafl oor decreases with increasing continental area. This study suggests that mantle heat loss experienced significant fl uctuations through continental growth and reinforces the estimate of <10% continental growth since the late Archean.

Long-term eustatic cyclicity in the Paleogene: a critical assessment

“…As younger age of the oceanic crust is an important control on the eustatic rise (e.g., Müller et al, 2008;Anderson and Anderson, 2010), the Precambrian global sea level might have reached (at least, episodically) a high position relative to the Phanerozoic and, in particular, the Paleogene, which features much larger plates (Seton et al, 2012). Such an interpretation is in agreement (at least, in part) with the outcome of modelling undertaken recently by Coltice et al (2014). The above-mentioned and other peculiarities of the Precambrian tectonics (including, first of all, the activity of mantle plumes (Gargaud et al, 2012;Gerya, 2014)) likely influenced global sea-level change on a large scale; possible changes in the crust production may also induce a cyclic pattern of these changes (Eriksson et al, 2004(Eriksson et al, , 2005(Eriksson et al, , 2012.…”

Influence of continental growth on mid‐ocean ridge depth

“…In Figure a, we plot our results of MOR crest depth variations in the “Modern,” “Archean,” and “Hadean” models (blue, green, and red, respectively) in units of transit times. The MOR depth variations for the “Modern” model with values ranging from ±100 to ±900 m, bracketing the range observed in previous models [ Coltice et al ., ], are an order of magnitude larger than that of ±50 m for the “Hadean” model. This is expected since on average the age of subducting oceanic crust is older for the “Modern” model.…”

“…Pseudoplasticity is implemented through a stress dependence of the viscosity with a yield stress [ Coltice et al ., , ]. We choose a nondimensional value of 15,000 to produce a plate‐like behavior and large‐scale convective flow.…”

“…Indeed, the ocean basin volume based on reconstructed seafloor age distributions since 140 Ma compares favorably with the observed long‐term trend of global sea level over the same time [ Müller et al ., ]. Additionally, the amount of Earth's surface covered by continents also drives significant variation of seafloor age distribution [ Coltice et al ., ] but the corresponding effect on global MOR depth has yet to be investigated. This study uses mantle convection models to address the question of how the depth of the MOR may have changed over geologic time.…”

Mantle convection, the asthenosphere, and Earth's thermal history

“…Modern numerical studies of mantle convection have addressed many of the unexplored complexities from the earlier studies including: non-linear temperature-dependent rheology (Torrence and Parmentier et al, 1976); compressibility (Jarvis and McKenzie, 1980;Leng and Zhong, 2008;King et al, 2010); three-dimensional geometry (c.f., Gable et al, 1991;Tackley et al, 1993;Lowman et al, 2001;2003;2004), self-consistent equations of state (Ita and King, 1994;1998;Nakagawa et al, 2009); spherical geometry (Schubert and Zebib, 1980;Hager and O'Connell, 1981;Bercovici et al, 1989;Tackley et al, 1993;Bunge et al, 1997;Anderson, 1997a, 1997b;Zhong et al, 2000); the role of plates and slabs (Gurnis and Hager, 1988;Gurnis and Zhong, 1991;Zhong and Gurnis, 1992;King and Hager, 1994;Bercovici, 1995;Chen and King, 1998;Trompert and Hansen, 1998;Tackley, 2000;Billen and Gurnis, 2003;Billen and Hirth, 2007;Tackley, 2008, 2011;Billen, 2008Billen, , 2010Coltice et al, 2013Coltice et al, ,2014.…”