气候变化领域集成服务门户(CCPortal): Impact of crust–mantle mechanical coupling on the topographic and thermal evolutions during the necking phase of ‘magma-poor’ and ‘sediment-starved’ rift systems: A numerical modeling study

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DOI	10.1016/j.tecto.2020.228472
	Impact of crust–mantle mechanical coupling on the topographic and thermal evolutions during the necking phase of ‘magma-poor’ and ‘sediment-starved’ rift systems: A numerical modeling study
	Chenin P.; Schmalholz S.M.; Manatschal G.; Duretz T.
发表日期	2020
ISSN	00401951
卷号	786
英文摘要	We used high-resolution (500 × 250 m) two-dimensional lithospheric-scale thermo-mechanical numerical modeling to unravel the unexpected topographic and thermal evolutions recorded during the necking phase of several rift systems worldwide. Through a systematic analysis we studied how the lithosphere rheology impacts the topographic and thermal evolutions across the entire width of magma-poor and sediment-starved rift systems until their crust is locally thinned to 10 km. We quantified the evolution of topography, uplift and subsidence rates, accommodation and emerged space creation, temperature and surface heat flow for a wide panel of crustal and mantle rheologies to provide an overview of possible rifting behaviors. Extension of a lithosphere for which the crust and mantle are mechanically decoupled by a weak lower crust generates complex morphotectonic evolutions, with the formation of temporarily restricted sub-basins framed by uplifted parts of the future distal margin. Mechanical decoupling between the crust and mantle controls also largely the thermal evolution of rift systems during the necking phase since, for equivalent extension rates and initial geotherms: (i) weak/decoupled lithospheres have a higher geothermal gradient at the end of the necking phase than strong/coupled lithospheres; and (ii) weak/decoupled lithospheres show intense heating of the lower crust at the rift center and intense cooling of the crust on either side of the rift center, unlike strong/coupled lithospheres. These behaviors contrast with the continuous subsidence and cooling predicted by the commonly used depth-uniform thinning model. Accommodation space in the evolving basins is first generated by vertical crustal velocities and subsequently by horizontal velocities causing the widening of the earlier formed basin. Processes such as strain softening and mantle fertilization have a limited impact on the primary morphology and thermal state of rift systems before the crust is thinned to 10 km but may locally amplify relief and thermal heterogeneities. © 2020 Elsevier B.V.
关键词	Necking Numerical modeling Rift Thermal evolution Topographic evolution
英文关键词	Ductile fracture; Elasticity; Numerical models; Subsidence; Topography; Accommodation space; Geothermal gradients; Horizontal velocity; Mechanical coupling; Surface heat flow; Systematic analysis; Thermal heterogeneity; Thermo-mechanical; Cooling systems; crust-mantle boundary; magma chamber; numerical model; rheology; rifting; subsidence; thermal evolution; thermomechanics; topography; Calluna vulgaris
语种	英语
来源期刊	Tectonophysics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/207730
作者单位	CNRS, IPGS, Université de Strasbourg, 1 Rue Blessig, Strasbourg, 67084, France; Institut des Sciences de la Terre, Université de Lausanne, Bâtiment Géopolis, Lausanne, CH-1015, Switzerland; CNRS, Géosciences-Rennes, Université de Rennes, BAT 14B, Campus Beaulieu, Rennes, 35042, France
推荐引用方式 GB/T 7714	Chenin P.,Schmalholz S.M.,Manatschal G.,等. Impact of crust–mantle mechanical coupling on the topographic and thermal evolutions during the necking phase of ‘magma-poor’ and ‘sediment-starved’ rift systems: A numerical modeling study[J],2020,786.
APA	Chenin P.,Schmalholz S.M.,Manatschal G.,&Duretz T..(2020).Impact of crust–mantle mechanical coupling on the topographic and thermal evolutions during the necking phase of ‘magma-poor’ and ‘sediment-starved’ rift systems: A numerical modeling study.Tectonophysics,786.
MLA	Chenin P.,et al."Impact of crust–mantle mechanical coupling on the topographic and thermal evolutions during the necking phase of ‘magma-poor’ and ‘sediment-starved’ rift systems: A numerical modeling study".Tectonophysics 786(2020).