Lithospheric Erosion in the Patagonian Slab Window, and Implications for Glacial Isostasy

Mark, Hannah; Wiens, Douglas A.; Ivins, E. R.; Richter, Andreas; Mansour, Walid; Magnani, M. B.; Marderwald, Eric; Adaros, Rodrigo; Barrientos, Sergio

doi:10.1029/2021gl096863

Cited by 18 publications

(32 citation statements)

References 78 publications

(118 reference statements)

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“…The region of inferred EW mantle flow around the Nazca slab coincides with a strong low velocity anomaly (Vsv < 4.1 km/s) in the uppermost mantle of the regional Vsv model [Mark et al, 2022].…”

Section: Toroidal Flow In the Uppermost Mantle Around The Nazca Slabmentioning

confidence: 69%

“…Slab windows provide an opportunity to study the strength and geographical pattern of toroidal flow at slab edges, as previously observed in the Mediterranean Sea [Civello and Margheriti, 2004] and the Western US [Zandt and Humphrey, 2008]. Recently, Mark et al (2022) proposed a thermal and mechanical erosion process to explain slow mantle velocity anomalies and thinning of the lithospheric mantle between the Nazca slab edge and the northern part of the Patagonia slab window between 46 ° and 49 °S.…”

Section: Introductionmentioning

confidence: 89%

“…This network fills a data gap between the previous deployments in the CTJ region in the north [Russo et al 2010a] and in southernmost Patagonia [Helffrich et al, 2002]. The GUANACO network was deployed from November 2018 to February 2021 and consisted of twenty-seven seismographs with station spacing of approximately 50 to 100 km [Mark et al, 2022]. The stations were equipped with Nanometrics Trillium-240 seismometers or Trillium Horizon sensors, and Quanterra Q330 dataloggers (see supplementary material).…”

Section: Datasets and Analysismentioning

confidence: 99%

“…From the analysis of short period group velocities derived from ambient noise cross-correlation, Gallego et al (2011) show the crust is affected by the slab window between 47 o S and 48 o S with relatively low shear wave velocity in comparison with the average velocity and significant anisotropy (1-2%). P-receiver function analyses [Rodriguez and Russo, 2020] show a crustal thickness of 28-35 km proximal to the CTJ and thickening crust from 34 km just north of the triple junction to ~55 km at 44 o S, with crustal thinning between 46.5 o S and 47 o S. In their joint inversion of converted body wave phases and Rayleigh wave dispersion derived from ambient noise and teleseismic earthquakes, Mark et al (2022) show crustal thickening from south to north over the slab window but also a thinning of the lithospheric mantle near the CTJ.…”

Section: Introductionmentioning

confidence: 99%

“…Here we present the results of a shear wave splitting analysis using SKS, SKKS and PKS phases to characterize the mantle flow pattern beneath Southern Patagonia. We process broadband seismograms from the recent GUANACO temporary deployment [Mark et al, 2022] as well as previous deployments to measure shear-wave splitting parameters using the minimization of transverse component energy method [Silver and Chan, 1991]. This new set of shear wave splitting measurements provides an extended view of the large-scale azimuthal anisotropy in southern South America and better constrains the mantle flow field associated with the Patagonia slab manuscript submitted to Geophysical Research Letters window.…”

Section: Introductionmentioning

confidence: 99%

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

Mansour¹,

Wiens²,

Mark³

et al. 2022

Preprint

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Geological processes in Southern Patagonia are affected by the Patagonian slab window, formed by the subduction of the Chile Ridge and subsequent northward migration of the Chile Triple Junction. Using shear wave splitting analysis, we observe strong splitting of up to 2.5 s with an E-W fast direction just south of the triple junction and the edge of the subducting Nazca slab. This region of strong anisotropy is coincident with low uppermost mantle shear velocities and an absence of mantle lithosphere, indicating that the mantle flow occurs in a warm, low-viscosity, 200-300 km wide shallow mantle channel just to the south of the Nazca slab. The region of flow corresponds to a volcanic gap caused by depleted mantle compositions and absence of slab-derived water. In most of Patagonia to the south of this channel, splitting fast directions trend NE-SW consistent with large-scale asthenospheric flow.

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Section: Toroidal Flow In the Uppermost Mantle Around The Nazca Slabmentioning

confidence: 69%

Section: Introductionmentioning

confidence: 89%

Section: Datasets and Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Mansour¹,

Wiens²,

Mark³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

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Anthropocene isostatic adjustment on an anelastic mantle

Ivins,

Caron,

Adhikari

2023

J Geod

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A general assumption in geodesy is that solid Earth deformation in the presence of recent hydrological and ice loading is well approximated by a purely elastic response. In cases where there is clear evidence that thermal and petrological conditions exist that favor vigorous high-temperature creep behavior, such as in the mantle beneath Iceland, Patagonia, Alaska, Japan, and Svalbard, many response models have been approximated by using a Maxwell viscoelasticity. However, non-Maxwellian transient viscoelastic rheology is required for many post-seismic relaxation studies. Here, we reconsider the solid Earth response in light of highly temperature-dependent transient viscoelastic responses currently favored in the mineral physics and seismological communities. We develop a mantle response Green’s function that accounts for the vertical isostatic motion of the mantle caused by the acceleration of ice mass loss for Greenland and Patagonia measured by spaceborne and airborne remote sensing since 1992 and 1945, respectively. The Green’s function may be used to examine how anelasticity influences the uplift associated with accelerated surface mass loss. We perform a parameter exploration of the constants that define the Extended Burgers Material model, a rheology having firm experimental and theoretical underpinnings, in order to isolate those material model parameters that have the greatest impact on anelastic-isostatic uplift over interannual and interdecadal timescales. Anelasticity corrections may be required for solid Earth vertical uplift in space gravimetric solutions for long-term hydrology and cryospheric change.

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