DOI: 10.1016/j.epsl.2017.10.024
Scopus记录号: 2-s2.0-85033694466
论文题名: Continental margin subsidence from shallow mantle convection: Example from West Africa
作者: Lodhia B.H. ; Roberts G.G. ; Fraser A.J. ; Fishwick S. ; Goes S. ; Jarvis J.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 481 起始页码: 350
结束页码: 361
语种: 英语
英文关键词: Cape Verde
; dynamic support
; small-scale mantle convection
; subsidence
; uplift
; West Africa
Scopus关键词: Bathymetry
; Sedimentary rocks
; Seismology
; Shear flow
; Shear waves
; Subsidence
; Tomography
; Cape Verde
; Dynamic supports
; Mantle convection
; uplift
; West Africa
; Tectonics
; continental margin
; mantle convection
; S-wave
; seismic data
; seismic velocity
; subsidence
; tomography
; uplift
; upper mantle
; Cape Verde [Dakar]
; Dakar [Senegal]
; Senegal
; Calluna vulgaris
英文摘要: Spatial and temporal evolution of the uppermost convecting mantle plays an important role in determining histories of magmatism, uplift, subsidence, erosion and deposition of sedimentary rock. Tomographic studies and mantle flow models suggest that changes in lithospheric thickness can focus convection and destabilize plates. Geologic observations that constrain the processes responsible for onset and evolution of shallow mantle convection are sparse. We integrate seismic, well, gravity, magmatic and tomographic information to determine the history of Neogene-Recent (<23 Ma) upper mantle convection from the Cape Verde swell to West Africa. Residual ocean-age depths of +2 km and oceanic heat flow anomalies of +16 ± 4 mW m−2 are centered on Cape Verde. Residual depths decrease eastward to zero at the fringe of the Mauritania basin. Backstripped wells and mapped seismic data show that 0.4–0.8 km of water-loaded subsidence occurred in a ∼500 × 500 km region centered on the Mauritania basin during the last 23 Ma. Conversion of shear wave velocities into temperature and simple isostatic calculations indicate that asthenospheric temperatures determine bathymetry from Cape Verde to West Africa. Calculated average excess temperatures beneath Cape Verde are >+100 °C providing ∼103 m of support. Beneath the Mauritania basin average excess temperatures are <−100 °C drawing down the lithosphere by ∼102 to 103 m. Up- and downwelling mantle has generated a bathymetric gradient of ∼1/300 at a wavelength of ∼103 km during the last ∼23 Ma. Our results suggest that asthenospheric flow away from upwelling mantle can generate downwelling beneath continental margins. © 2017 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110185
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
There are no files associated with this item.
作者单位: Department of Earth Science and Engineering, Imperial College London, South Kensington CampusSW7 2AZ, United Kingdom; Department of Geology, University of Leicester, Leicester, LE1 7RH, United Kingdom; Tullow Oil Plc., Chiswick Park, 566 Chiswick High Road, London, W4 5XT, United Kingdom
Recommended Citation:
Lodhia B.H.,Roberts G.G.,Fraser A.J.,et al. Continental margin subsidence from shallow mantle convection: Example from West Africa[J]. Earth and Planetary Science Letters,2018-01-01,481