DOI: 10.1016/j.epsl.2018.03.044
Scopus记录号: 2-s2.0-85045403718
论文题名: Ps mantle transition zone imaging beneath the Colorado Rocky Mountains: Evidence for an upwelling hydrous mantle
作者: Zhang Z. ; Dueker K.G. ; Huang H.-H.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 492 起始页码: 197
结束页码: 205
语种: 英语
英文关键词: 410 and 660 velocity discontinuities
; Colorado Rocky Mountains
; mantle hydration
; receiver function analysis
Scopus关键词: Hydration
; Image segmentation
; Landforms
; Olivine
; Seismology
; Shear waves
; Silicate minerals
; Tomography
; Velocity
; 410 and 660 velocity discontinuities
; 410-km discontinuity
; Convective downwelling
; High-resolution imaging
; Mantle transition zone
; Receiver function analysis
; Rocky Mountains
; Synthetic seismogram
; Phase transitions
; deconvolution
; imaging method
; mantle source
; P-wave
; S-wave
; seismic data
; seismic tomography
; seismic velocity
; teleseismic wave
; transition zone
; Colorado
; Rocky Mountains
; United States
英文摘要: We analyze teleseismic P-to-S conversions for high-resolution imaging of the mantle transition zone beneath the Colorado Rocky Mountains using data from a dense PASSCAL seismic broadband deployment. A total of 6,021 P-to-S converted receiver functions are constructed using a multi-channel minimum-phase deconvolution method and migrated using the common converted point technique with the 3-D teleseismic P- and S-wave tomography models of Schmandt and Humphreys (2010). The image finds that the average depths of the 410-km discontinuity (the 410) and 660-km discontinuity (the 660) at 408±1.9 km and 649±1.6 km respectively. The peak-to-peak topography of both discontinuities is 33 km and 27 km respectively. Additionally, prominent negative polarity phases are imaged both above and below the 410. To quantify the mean properties of the low-velocity layers about 410 km, we utilize double gradient layer models parameterization to fit the mean receiver function waveform. This waveform fitting is accomplished as a grid-search using anelastic synthetic seismograms. The best-fitting model reveals that the olivine–wadsleyite phase transformation width is 21 km, which is significantly larger than anhydrous mineral physics prediction (4–10 km) (Smyth and Frost, 2002). The findings of a wide olivine–wadsleyite phase transformation and the negative polarity phases above and below the 410, suggest that the mantle, at least in the 350–450 km depth range, is significantly hydrated. Furthermore, a conspicuous negative polarity phase below the 660 is imaged in high velocity region, we speculate the low velocity layer is due to dehydration flux melting in an area of convective downwelling. Our interpretation of these results, in tandem with the tomographic image of a Farallon slab segment at 800 km beneath the region (Schmandt and Humphreys, 2010), is that hydrous and upwelling mantle contributes to the high-standing Colorado Rocky Mountains. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109887
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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Recommended Citation:
Zhang Z.,Dueker K.G.,Huang H.-H.. Ps mantle transition zone imaging beneath the Colorado Rocky Mountains: Evidence for an upwelling hydrous mantle[J]. Earth and Planetary Science Letters,2018-01-01,492