Seismic structure and origin of hotspots and mantle plumes

By Dapeng Zhao. 2001

365 citations recorded by the source corpus.

Abstract A new global tomography approach has been used to study the deep structure and dynamics of hotspots and mantle plumes. In this approach, depth variations of the Moho, 410 and 660 km discontinuities are considered, the Earth structure is expressed by seismic velocities at grid nodes instead of blocks, and ray paths and travel times are calculated with a 3-D ray tracing technique. Prominent plume-like slow anomalies are detected under major hotspot regions from the crust down to the core–mantle boundary (CMB). Hotspots in Hawaii, Iceland, South Pacific and East Africa are located above slow anomalies in the lower mantle down to the CMB, suggesting that the mantle plumes under those hotspots may originate from the CMB. However, there may be some small-scaled, weak plumes originating from the transition zone or middle mantle depths. The slow anomalies under hotspots usually do not show a vertical pillar shape, which suggests that plumes are not fixed in the mantle but can be deflected by the mantle flow. As a consequence, hotspots are not fixed but can wander on the Earth’s surface, as evidenced by recent geomagnetic and numerical modeling studies.

Subfields: Geophysics

View Paper: https://www.semanticscholar.org/paper/ac3267d73616cc6c643c938705ee0692cd0a3b83

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In Geophysics

1. Yu Jeffrey Gu
2. K. Hirose
3. Qinya Liu
4. Artem R. Oganov
5. Shigeaki Ono
6. L. Chiao
7. Jun Korenaga
8. Yang Shen

Citations in the corpus

• Observational and theoretical studies of the dynamics of mantle plume–mid‐ocean ridge interaction (2003, background): “[15] Recent efforts have been made to test the plume hypothesis by seismically imaging the mantle beneath hot spots [e.g., Zhang and Tanimoto, 1992; Wolfe et al., 1997; Shen et al., 1998; Allen et al., 1999; Bijwaard and Spakman, 1999; Foulger et al., 2001; Toomey et al., 2001; Zhao, 2001].”
• Multiscale seismic tomography and mantle dynamics (2009, background): “The Pacific superplume has a larger spatial extent and stronger slow anomalies than that of the Africa superplume.”
• Imaging seismic velocity structure beneath the Iceland hot spot: A finite frequency approach (2004, background): “…studies have revealed low compressional (P) and shear (S) wave speeds beneath Iceland at both regional and global scales [Tryggvason et al., 1983; Wolfe et al., 1997; Bijwaard and Spakman, 1999; Ritsema et al., 1999; Foulger et al., 2000; Zhao, 2001; Allen et al., 2002b; Montelli et al., 2004].”
• LINKS BETWEEN LONG‐LIVED HOT SPOTS, MANTLE PLUMES, D″, AND PLATE TECTONICS (2004, neutral): “…Su and Dziewonski, 1991; Garnero and Helmberger, 1993; Grand, 1994; Su et al., 1994; Wysession, 1996; Garnero and Helmberger, 1996; Vasco and Johnson, 1998; Ritsema et al., 1999; Masters et al., 2000; Kuo et al., 2000; Megnin and Romanowicz, 2000; Castle et al., 2000; Romanowicz, 2001; Zhao, 2001].”
• Seismic imaging: From classical to adjoint tomography (2012, background): “…Tanimoto, 1992; Zhou and Clayton, 1990), plate boundary zones (e.g., Fukao et al., 1992; Nishimura and Forsyth, 1989; van der Hilst et al., 1991; Zhao, 2001a; Zhao et al., 1994), upper mantle transition zone (Becker et al., 2003; Gu et al., 2001; Mégnin and Romanowicz, 2000; Widiyantoro and van…”
• Urey ratio and the structure and evolution of Earth's mantle (2008, background): “(Note that some studies have presented a tomographic image for a deep Icelandic plume [Bijwaard and Spakman, 1999; Zhao, 2001], but it appears to be an artifact of the use of an oversaturated color scale [Foulger and Pearson, 2001].”
• LLNL‐G3Dv3: Global P wave tomography model for improved regional and teleseismic travel time prediction (2012, background): “…deep within the Earth [e.g., Obayashi et al., 1997; Su and Dziewonski, 1997; van der Hilst et al., 1997; Bijwaard et al., 1998; Kennett et al., 1998; Boschi and Dziewonski, 1999; Masters et al., 2000; Zhao, 2001, 2009; Fukao et al., 2003; Houser et al., 2008; Li et al., 2008; Simmons et al., 2010].”
• On the Causes of Electrical Conductivity Anomalies in Tectonically Stable Lithosphere (2013, neutral): “boundary (Hofmann 1997; Zhao 2001).”
• In situ observations of phase transition between perovskite and CaIrO3-type phase in MgSiO3 and pyrolitic mantle composition (2005, background): “Seismic tomography images show that a large low-velocity region exists above the VSHbVSV region in the lower mantle [88].”
• Postperovskite phase transition and its geophysical implications (2006, result): “This is not consistent with the seismic observations that a couple of large-scale upwellings beneath central Pacific and Africa dominate in the lower mantle [e.g., Fukao et al., 1992; Zhao, 2001].”
• Mantle shear–wave tomography and the fate of subducted slabs (2002, neutral): “(1998) and Zhao (2001).”