On the Relative Importance of Buoyancy and Thickening of Aging Lithosphere in Mantle Upwelling and Crustal Production Beneath Global Mid-Ocean Ridge System

Zha，Caicai1,2; Zhang，Fan1,2; Lin，Jian1,2,3; Zhang，Tao4; Tian，Jinyu3,5

2024-05-01

10.1029/2023JB028432

Journal of Geophysical Research: Solid Earth   影响因子和分区

2169-9313

2169-9356

Beneath mid-ocean ridges, mantle upwelling and decompression melting are fundamental processes contributing to the formation of oceanic crust. Previous geodynamic models have suggested that mantle upwelling driven by separating plates can be intensified by thermochemical buoyancy and the thickening of aging lithosphere, resulting in thicker crust. However, the relative contributions of these factors to crustal accretion remain uncertain. We conducted numerical modeling in three scenarios to investigate this: (a) buoyant flow models incorporating age-dependent lithospheric thickening as a reference; (b) passive flow models incorporating age-dependent lithospheric thickening to isolate the effect of buoyancy; and (c) passive flow models that neglect age-dependent lithospheric thickening to isolate its effect. Models are performed under varying potential mantle temperatures (Tp), viscosity structures, and spreading rates. The model-predicted crustal thickness suggests that both buoyancy and thickening of aging lithosphere increasingly contribute to crustal production as spreading rate decreases. However, given the range of reference mantle viscosities examined here (10–10 Pa s), except in ultraslow spreading rates with lower reference viscosity and warmer Tp, the impact of the thickening of aging lithosphere predominates over buoyancy. Furthermore, the relative importance of buoyancy-induced crustal production increases as spreading rates decrease. Variations in Tp further amplify the variability in crustal thickness compared to that at fast-spreading ridges where passive upwelling dominates, when combined with 3-D effects of buoyant flow on altering axial crustal production at ultraslow-spreading ridge segments. This 4-D effects of buoyant flow on melt production may explain the observed more variable crustal thickness at ultraslow-spreading ridges.

SCI

英语

其他

GEOSCIENCES

2-s2.0-85192837677

Scopus

1.Key Laboratory of Ocean and Marginal Sea Geology,South China Sea Institute of Oceanology,Innovation Academy of South China Sea Ecology and Environmental Engineering,Chinese Academy of Sciences,Guangzhou,China
2.China-Pakistan Joint Research Center on Earth Sciences,CAS-HEC,Islamabad,Pakistan
3.Department of Ocean Science and Engineering,Southern University of Science and Technology,Shenzhen,China
4.Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou,China
5.Key Laboratory of Hydrodynamics (Ministry of Education),School of Ocean and Civil Engineering,Shanghai Jiao Tong University,Shanghai,China

Zha，Caicai,Zhang，Fan,Lin，Jian,et al. On the Relative Importance of Buoyancy and Thickening of Aging Lithosphere in Mantle Upwelling and Crustal Production Beneath Global Mid-Ocean Ridge System[J]. Journal of Geophysical Research: Solid Earth,2024,129(5).

Zha，Caicai,Zhang，Fan,Lin，Jian,Zhang，Tao,&Tian，Jinyu.(2024).On the Relative Importance of Buoyancy and Thickening of Aging Lithosphere in Mantle Upwelling and Crustal Production Beneath Global Mid-Ocean Ridge System.Journal of Geophysical Research: Solid Earth,129(5).

Zha，Caicai,et al."On the Relative Importance of Buoyancy and Thickening of Aging Lithosphere in Mantle Upwelling and Crustal Production Beneath Global Mid-Ocean Ridge System".Journal of Geophysical Research: Solid Earth 129.5(2024).