Connection Between a Subcontinental Plume and the Mid‐Lithospheric Discontinuity Leads to Fast and Intense Craton Lithospheric Thinning

Abstract

Thinning of these cratonic lithospheres has occurred under different tectonic settings, in particular being associated with interactions with nearby oceanic subduction or an underlying mantle plume. Lithospheric thinning beneath the North China Craton and the Wyoming Craton in North America is generally considered to be related to subduction-induced lithospheric modification (Figure 1). For example, the lithospheric thickness of the North China Craton was reduced from 200 to 100 km since the Paleozoic (

Plume‐Lithosphere Interaction and Delamination at Yellowstone and Its Implications for the Boundary of Craton Stability

“…Many mechanisms have been proposed to explain the origin and dynamics of cratonic thinning and destruction (Hu et al, 2018;Liu et al, 2018aLiu et al, , 2018bLiu & Li, 2018;Shi et al, 2020Shi et al, , 2021Windley et al, 2010;Wu et al, 2014;Yang & Leng, 2014;Zhu et al, 2012;Wang & Kusky, 2019). Recent numerical models indicate that the interaction between subduction zones and/or plumes and a weak MLD layer can result in the delamination of the lower lithospheric keels (Hu et al, 2018;Liu et al, 2018aLiu et al, , 2018bShi et al, 2020Shi et al, , 2021Wang & Kusky, 2019; and references therein). Another typical characteristic of the cratons that have experienced thinning and destruction is that only part of those cratons has been modified while the rest remains stable.…”

“…While most continental lithosphere appears to be stable due to its high viscosity and relatively low density (Carlson et al, 2005;Wang et al, 2014;Jordan, 1988;Sleep, 2003;Lee et al, 2011), some regions have experienced lithospheric thinning and removal under different tectonic settings (Bird, 1979;Griffin et al, 1998;Lee et al, 2011;Menzies et al, 2007;Sleep, 2003;Wu et al, 2014). Many mechanisms have been proposed to explain the origin and dynamics of cratonic thinning and destruction (Hu et al, 2018;Liu et al, 2018aLiu et al, , 2018bLiu & Li, 2018;Shi et al, 2020Shi et al, , 2021Windley et al, 2010;Wu et al, 2014;Yang & Leng, 2014;Zhu et al, 2012;Wang & Kusky, 2019). Recent numerical models indicate that the interaction between subduction zones and/or plumes and a weak MLD layer can result in the delamination of the lower lithospheric keels (Hu et al, 2018;Liu et al, 2018aLiu et al, , 2018bShi et al, 2020Shi et al, , 2021Wang & Kusky, 2019; and references therein).…”

“…Such linear weak zones can act as the horizontal boundaries to where lithospheric delamination would take place. When plume material flows beneath a region, there is the enhanced potential for the delamination of one (or more) lithospheric fragments bounded by vertical weak zones in the lithosphere, so long as a semi‐continuous MLD is present above the delaminating region (Shi et al., 2021).…”

“…The goals of these experiments were both to further study the dynamics of recent plume‐lithosphere interaction in the Yellowstone region (albeit in an idealized 2D geometry), and also to make an initial exploration of the factors that can potentially shape the lateral extent of plumed‐enhanced lithosphere delamination (Figure 2a). The spatial resolution of the model is 2 × 2 km in the central area, gradually increasing to 30 × 30 km at margins far away from the region of interest (e.g., Gerya & Yuen, 2003a, 2003b; Shi et al., 2021).…”

“…The relatively weak MLD layer is set at a depth of 100 km with a thickness of 20 km in the reference model (Griffin et al, 1999(Griffin et al, , 2004Selway et al, 2015;Shi et al, 2020). It is assumed to have a constant viscosity of 3 × 10 19 Pa s. We recently used the same parameters when exploring both subduction-and plume-induced delamination (Shi et al, 2020(Shi et al, , 2021. Once a mechanical flow connection would occur through a pre-existing vertical weak zone between uprising weak material from the mantle and the weak MLD layer, then a favorable condition for delamination would exist that would lead to lower continental lithosphere delamination as initially proposed by Bird (1979).…”