Numerical study on the style of delamination

An Asthenospheric Upwelling Beneath Central Mongolia — Implications for Intraplate Surface Uplift and Volcanism

“…In light of these results, a geodynamic investigation using self-consistent thermo-mechanical numerical modeling is used to explore whether potential explanations for the underlying mechanisms causing intraplate surface uplift are physically plausible (Comeau et al, 2021b; see also Stein et al, 2021). To keep the modeling realistic, constraints on input parameters are based on the geophysical results (magnetotellurics and seismics) as well as on the geological and geochemical data -a step towards integrating multi-disciplinary studies.…”

“…By systematically varying physical parameters, their influence and control on the style and timing of lithospheric removal and asthenospheric upwelling, as well as surface deformation, is tested (Comeau et al, 2021b;Stein et al, 2021). Lithospheric removal is allowed to develop dynamically by applying a phase transition and density jump -hypothesized to be a consequence of metamorphic eclogitization in a thickened crust -rather than simply imposing an initial dense block to initiate instability.…”

Magnetotelluric Imaging of the Central Himalayan Crust Away From Rift Zones

“…In addition, this Indian lower crust with moderate resistivity may correspond to the possible eclogitization within a doublet layer, which is characterized by high P‐wave velocity (Schulte‐Pelkum et al., 2005), high density (Hetényi et al., 2007) and low Vp/Vs ratios (Wittlinger et al., 2009) beneath the High Himalaya, Tethyan Himalaya and Lhasa Terrane (Shi et al., 2016). Since large‐scale and pervasive conversion to eclogites can result in the delamination of the denser material, the Indian lower crust could be dragged beneath the north Himalayas (Guo et al., 2017; Stein et al., 2022), and it may even further lead to internal rupture of the Indian crust. We currently have no experimental data to clarify the composition of the Indian lower crust, but it is time for this moderately resistive layer to attract widespread attention from future studies.…”

Insights Into the Structure of the Mongol‐Okhotsk Suture Zone, Adaatsag Ophiolite, and Tectonic Boundaries of the Central Asian Orogenic Belt (Mongolia) From Electrical Resistivity Imaging and Seismic Velocity Models

“…Dehydration melting from subducting oceanic plates, including from previous events in the CAOB before the formation of the Mongol-Okhotsk region, would have hydrated the lithosphere and led to (alkaline) metasomatism of the lithospheric mantle (Tomurtogoo et al, 2005). This may have established conditions in the region for a subsequent delamination event (see Comeau et al, 2021;Stein et al, 2022;Tomurtogoo et al, 2005). In fact, geochemical data indicate that metasomatism of a hydrated lithosphere likely occurred beneath parts of Mongolia near the Mongol-Okhotsk suture zone (Sheldrick et al, 2020).…”

“…In fact, geochemical data indicate that metasomatism of a hydrated lithosphere likely occurred beneath parts of Mongolia near the Mongol‐Okhotsk suture zone (Sheldrick et al., 2020). Furthermore, thermo‐mechanical numerical modeling has shown that deep (lithospheric‐scale) faults or sutures, which may have significantly different properties (e.g., rheological and chemical) from the surrounding regions (e.g., Jin et al., 2022), can act to focus deformation and are therefore important initiation points for detachment of the lithosphere (Comeau et al., 2021; Stein et al., 2022).…”