Subduction of the Chile Ridge: Upper mantle structure and flow

  title={Subduction of the Chile Ridge: Upper mantle structure and flow},
  author={Raymond M. Russo and John C. VanDecar and Diana Comte and Victor I. Mocanu and Alejandro Gallego and Ruth E. Murdie},
  journal={Gsa Today},
We deployed 39 broadband seismometers in southern Chile from Dec. 2004 to Feb. 2007 to determine lithosphere and upper mantle structure in the vicinity of the subducting Chile Ridge. Body-wave travel-time tomography clearly shows the existence of a long-hypothesized slab window, a gap between the subducted Nazca and Antarctic lithospheres. P-wave velocities in the slab gap are distinctly slow relative to surrounding asthenospheric mantle. Thus, the gap between slabs visible in the imaging… 

Figures from this paper

Source-side shear wave splitting and upper mantle flow in the Chile Ridge subduction region

The actively spreading Chile Ridge has been subducting beneath Patagonian Chile since the Middle Miocene. After subduction, continued separation of the faster Nazca plate from the slow Antarctic

Mantle flow pattern associated with the Patagonian slab window determined from azimuthal anisotropy

Geological processes in Southern Patagonia are affected by the Patagonian slab window, formed 23 by the subduction of the Chile Ridge and subsequent northward migration of the Chile Triple 24

Azimuthal anisotropy in the Chile Ridge subduction region retrieved from ambient noise

In the southern Andes, the oblique convergence of the Nazca plate and the subduction of an active oceanic ridge represent two major tec- tonic features driving deformation of the forearc in the

Detailed Structure of the Subducted Nazca Slab into the Lower Mantle Derived From Continent‐Scale Teleseismic P Wave Tomography

Nazca subduction beneath South America is one of our best modern examples of long‐lived ocean‐continent subduction on the planet, serving as a foundation for our understanding of subduction

Three‐dimensional mantle circulations and lateral slab deformation in the southern Chilean subduction zone

The along‐strike variation in plate properties is a common feature in the subduction zones. The southern Chilean subduction is a notable example where the slab age and length, and the thickness of

Seismic anisotropy above and below the subducting Nazca lithosphere in southern South America

[1] The goal of this study is to better constrain anisotropy and mantle flow above and below the Nazca slab from 28°S to 42°S through modeling of shear wave splitting in local S, SKS and SKKS

Mantle subducting slab structure in the region of the 2010 M8.8 Maule earthquake (30–40°S), Chile

We present a new tomographic model of the mantle in the area of the 2010 M8.8 Maule earthquake and surrounding regions. Increased ray coverage provided by the aftershock data allows us to image the

Seismotectonic implications of the South Chile ridge subduction beneath the Patagonian Andes

The South Chile ridge (SCR) intersects the Patagonian trench around 46°09′S, forming the triple junction among the Antarctic, Nazca, and South America plates. Subduction of the SCR since ~18 Ma



Anisotropy and mantle flow in the Chile-Argentina subduction zone from shear wave splitting analysis

We examine shear wave splitting in teleseismic phases to observe seismic anisotropy in the South American subduction zone. Data is from the CHARGE network, which traversed Chile and western Argentina

Trench-Parallel Flow Beneath the Nazca Plate from Seismic Anisotropy

Trenchparallel flow may explain the eastward motions of the Caribbean and Scotia sea plates, the anomalously shallow bathymetry of the eastern Nazca plate, the long-wavelength geoid high over western South America, and it may contribute to the high elevation and intense deformation of the central Andes.

Mantle anisotropy beneath northwest Pacific subduction zones

To assess the location, strength, and orientation of seismic anisotropy in the southern Kuril, Japan, and Izu-Bonin subduction zones, we analyzed shear wave splitting in local S phases and

Complex mantle flow in the Mariana subduction system: evidence from shear wave splitting

SUMMARY Shear wave splitting measurements provide significant information about subduction zone mantle flow, which is closely tied to plate motions, lithospheric deformation, arc volcanism, and

Shear wave splitting and subcontinental mantle deformation

splitting observations are interpreted in terms of the strain-induced lattice preferred orientation of mantle minerals, especially olivine. We consider three hypotheses concerning the origin of the

Aseismic continuation of the Lesser Antilles slab beneath continental South America

[1] We present results of travel time inversions of teleseismic P and S waves recorded at the SECaSA92 (Southeast Caribbean South America 1992) temporary broadband array in northeastern Venezuela and

Interaction between the Chile Ridge and Chile Trench: Geophysical and geothermal evidence

Geophysical and geothermal data are examined from the three southernmost sections of the Chile Ridge, starting at 44°S and continuing south to the triple junction of the Nazca, Antarctic, and South

Geochemical confirmation of the Kula-Farallon slab window beneath the Pacific Northwest in Eocene time

Plate tectonic models indicate subduction of the Kula-Farallon spreading ridge, and thus imply formation of the Kula-Farallon slab window, beneath western North America from Late Cretaceous to middle