Global thermal models of the lithosphere

Cammarano, Fabio; Guerri, Mattia

doi:10.1093/gji/ggx144

Cited by 40 publications

(35 citation statements)

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“…In all profiles, the transition to thick lithosphere occurs >700 km inboard of the western Proterozoic rift margin. In the east coast, global lithospheric thickness models (e.g., Cammarano & Guerri, 2017;Dalton et al, 2017;Steinberger & Becker, 2016) overestimate lithospheric thickness when compared with regional tomography (e.g., Pollitz & Mooney, 2016;Porter et al, 2016;Schmandt et al, 2015;Schmandt & Lin, 2014;Shen & Ritzwoller, 2016;Wagner et al, 2018). Therefore, we defined an approximate eastern bound to the thick lithosphere based on these models.…”

Section: The Lithosphere-asthenosphere Boundarymentioning

confidence: 99%

“…The LAB in the Eastern U.S LAB properties in the eastern U.S. are much less certain than in the rest of the contiguous U.S. Occupying the middle ground of Paleozoic to Mesozoic aged lithosphere, previous estimates of lithospheric thickness in many global models are of intermediate depth (130-160 km on average, ranging from 90 to 215 km) (e.g., Artemieva, 2006;Cammarano & Guerri, 2017;Dalton et al, 2017;Steinberger & Becker, 2016). However, regional tomography models (and some global models (e.g., Schaeffer & Lebedev, 2013) reveal a more complex picture, varying from apparently thick lithosphere (150 km) to locally very thin (60 km) in the vicinity of well documented low velocity anomalies in New England and Virginia (e.g., Schmandt et al, 2015;Schmandt & Lin, 2014;Shen & Ritzwoller, 2016;Pollitz & Mooney, 2016;Porter et al, 2016;Wagner et al, 2018).…”

Section: The Lab Beneath the Cratonic Usmentioning

confidence: 99%

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The Changing Face of the Lithosphere‐Asthenosphere Boundary: Imaging Continental Scale Patterns in Upper Mantle Structure Across the Contiguous U.S. With Sp Converted Waves

Hopper

Fischer

2018

Geochem Geophys Geosyst

152

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Juxtaposed terranes of highly varied tectonic history make up the contiguous U.S.: the tectonically active western U.S., the largely quiescent Archean and Proterozoic cratons of the central U.S., and the Phanerozoic orogen and rifted margin of the eastern U.S. The transitions between these regions are clearly observed with Sp converted wave images of the uppermost mantle. We use common conversion point stacked Sp waves recorded by EarthScope's Transportable Array and other permanent and temporary broadband stations to image the transition from a strong velocity decrease at the lithosphere‐asthenosphere boundary (or LAB) beneath the western U.S. to deeper, less continuous features moving east that largely lie within the lithosphere. Only sparse, localized, weak phases are seen at LAB depths beneath the cratonic interior. Instead, we observe structures within the cratonic lithosphere that are most prominent within the Archean lithosphere of the Superior Craton. The transition from west to east is clearly revealed by cluster analysis, which also shows eastern U.S. mantle velocity gradients as more similar to the western U.S. than the ancient interior, particularly beneath New England and Virginia. In the western U.S., the observed strong LAB indicates a large enough velocity gradient (an average velocity drop of 10 ± 4.5% distributed over 30 ± 15 km) to imply that melt has ponded beneath the lithosphere.

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Section: The Lithosphere-asthenosphere Boundarymentioning

confidence: 99%

Section: The Lab Beneath the Cratonic Usmentioning

confidence: 99%

The Changing Face of the Lithosphere‐Asthenosphere Boundary: Imaging Continental Scale Patterns in Upper Mantle Structure Across the Contiguous U.S. With Sp Converted Waves

Hopper

Fischer

2018

Geochem Geophys Geosyst

152

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“…These are obtained by robust, linear fitting of lower crustal temperatures (less prone to be incorrect due to a possible underestimation of porosity) underneath each station, assuming a surface temperature of 18 • C. This allows to obtain a reasonable and representative value of geothermal gradient from seismic velocities, possibly reducing the bias associated with the specific seismic model used. In fact, as shown in Cammarano and Guerri (2017), seismic models can have rather different absolute velocities (and likewise the inferred temperatures) despite a high degree of similarity in their spatial patterns. The error on the estimate of geothermal gradient is evaluated considering the 68.3% (1 ) confidence interval of the slope of the best fitting line.…”

Section: Temperature At Depthmentioning

confidence: 94%

Inferring Crustal Temperatures Beneath Italy From Joint Inversion of Receiver Functions and Surface Waves

et al. 2019

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Temperature distribution at depth is of key importance for characterizing the crust, defining its mechanical behavior and deformation. Temperature can be retrieved by heat flow measurements in boreholes that are sparse, shallow, and have limited reliability, especially in active and recently active areas. Laboratory data and thermodynamic modeling demonstrate that temperature exerts a strong control on the seismic properties of rocks, supporting the hypothesis that seismic data can be used to constrain the crustal thermal structure. We use Rayleigh wave dispersion curves and receiver functions, jointly inverted with a transdimensional Monte Carlo Markov Chain algorithm, to retrieve the VS and VP/VS within the crust in the Italian peninsula. The high values (>1.9) of VP/VS suggest the presence of filled‐fluid cracks in the middle and lower crust. Intracrustal discontinuities associated with large values of VP/VS are interpreted as the α−β quartz transition and used to estimate geothermal gradients. These are in agreement with the temperatures inferred from shear wave velocities and exhibit a behavior consistent with the known tectonic and geodynamic setting of the Italian peninsula. We argue that such methods, based on seismological observables, provide a viable alternative to heat flow measurements for inferring crustal thermal structure.

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“…It can be noted that both approaches require the knowledge of an upper mantle density model: in the former, this model is used just to set z − V and the below density distribution (from z − V to z − V ) is unknown in the inversion, while in the latter, the densities from z − V to z − V are supposed known and their effects are removed from the observations. Since the current knowledge of the mantle density distribution is still uncertain, within this work, we analyzed 11 tomographic models (see Table 1) converted to density models according to different hypothesis for a total of 79 models (see [16] for details). Figure 2 shows the average density and the corresponding STD as functions of depth, computed from the different models in the study region.…”

Section: Model Volume Vmentioning

confidence: 99%

Practical Tips for 3D Regional Gravity Inversion

Sampietro¹,

Capponi

2019

Geosciences

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To solve the inverse gravimetric problem, i.e., to estimate the mass density distribution that generates a certain gravitational field, at local or regional scale, several parameters have to be defined such as the dimension of the 3D region to be considered for the inversion, its spatial resolution, the size of its border, etc. Determining the ideal setting for these parameters is in general difficult: theoretical solutions are usually not possible, while empirical ones strongly depend on the specific target of the inversion and on the experience of the user performing the computation. The aim of the present work is to discuss empirical strategies to set these parameters in such a way to avoid distortions and errors within the inversion. In particular, the discussion is focused on the choice of the volume of the model to be inverted, the size of its boundary, its spatial resolution, and the spatial resolution of the a-priori information to be used within the data reduction. The magnitude of the possible effects due to a wrong choice of the above parameters is also discussed by means of numerical examples.

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Global thermal models of the lithosphere

Cited by 40 publications

References 50 publications

The Changing Face of the Lithosphere‐Asthenosphere Boundary: Imaging Continental Scale Patterns in Upper Mantle Structure Across the Contiguous U.S. With Sp Converted Waves

The Changing Face of the Lithosphere‐Asthenosphere Boundary: Imaging Continental Scale Patterns in Upper Mantle Structure Across the Contiguous U.S. With Sp Converted Waves

Inferring Crustal Temperatures Beneath Italy From Joint Inversion of Receiver Functions and Surface Waves

Practical Tips for 3D Regional Gravity Inversion

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