Crust and Lithospheric Structure - Global Crustal Structure

Mooney, Walter D.

doi:10.1016/b978-0-444-53802-4.00010-5

Cited by 41 publications

(33 citation statements)

References 750 publications

(339 reference statements)

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“…The continental and oceanic crust comprises <1% by volume of planet Earth, but their importance to our planet far outweighs their contribution by volume. The crust holds the record of Earth's development through geologic time, its natural resources, and it is fundamental to societal challenges such as earthquakes and volcanic eruptions [Mooney, 2015]. Seismic methods have developed significantly in the Figure 1.…”

Section: Seismic Properties Of the Continental Crustmentioning

confidence: 99%

“…Seismic methods have developed significantly in the Figure 1. Crustal thickness map, adapted from Mooney [2015]. Red contour lines indicate 10 km intervals.…”

Section: Seismic Properties Of the Continental Crustmentioning

confidence: 99%

“…past 25 years, yielding a highly resolved picture of the continental crust. Depth to the Moho underneath continents is generally between 30 and 50 km, but it can range from 25 to 70 km ( Figure 1) [Mooney, 2015].…”

Section: Seismic Properties Of the Continental Crustmentioning

confidence: 99%

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Seismic properties and anisotropy of the continental crust: Predictions based on mineral texture and rock microstructure

Almqvist

Mainprice

2017

Reviews of Geophysics

164

127

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Progress in seismic methodology and ambitious large‐scale seismic projects are enabling high‐resolution imaging of the continental crust. The ability to constrain interpretations of crustal seismic data is based on laboratory measurements on rock samples and calculations of seismic properties. Seismic velocity calculations and their directional dependence are based on the rock microfabric, which consists of mineral aggregate properties including crystallographic preferred orientation (CPO), grain shape and distribution, grain boundary distribution, and misorientation within grains. Single‐mineral elastic constants and density are crucial for predicting seismic velocities, preferably at conditions that span the crust. However, high‐temperature and high‐pressure elastic constant data are not as common as those determined at standard temperature and pressure (STP; atmospheric conditions). Continental crust has a very diverse mineral composition; however, a select number of minerals appear to dominate seismic properties because of their high‐volume fraction contribution. Calculations of microfabric‐based seismic properties and anisotropy are performed with averaging methods that in their simplest form takes into account the CPO and modal mineral composition, and corresponding single crystal elastic constants. More complex methods can take into account other microstructural characteristics, including the grain shape and distribution of mineral grains and cracks and pores. Dynamic or active wave propagation schemes have recently been developed, which offer a complementary method to existing static averaging methods generally based on the use of the Christoffel equation. A challenge for the geophysics and rock physics communities is the separation of intrinsic factors affecting seismic anisotropy, due to properties of crystals within a rock and apparent sources due to extrinsic factors like cracks, fractures, and alteration. This is of particular importance when trying to deduce crustal composition and the state of deformation from seismic parameters.

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Section: Seismic Properties Of the Continental Crustmentioning

confidence: 99%

“…Seismic methods have developed significantly in the Figure 1. Crustal thickness map, adapted from Mooney [2015]. Red contour lines indicate 10 km intervals.…”

Section: Seismic Properties Of the Continental Crustmentioning

confidence: 99%

See 1 more Smart Citation

Seismic properties and anisotropy of the continental crust: Predictions based on mineral texture and rock microstructure

Almqvist

Mainprice

2017

Reviews of Geophysics

164

127

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“…Both models used the ETOPO1 topography/bathymetry global model and the total sediment thickness model by Laske and Masters (1997). Szwillus et al (2019) applied a geostatistical interpolation technique to obtain a depth to seismic Moho grid and associated uncertainties based on the USGS Global Seismic Catalogue (Mooney, 2015), which was also used in the construction of CRUST 1.0 model. The original CRUST 1.0 database has very few seismic observations in the high Arctic, whereas the uncertainty of Moho depth exceeds 10 km, especially in the central and eastern parts of the polar region ( Figure S8).…”

Section: Comparison With Global Crustal Models and Usefulness Of An Umentioning

confidence: 99%

ArcCRUST: Arctic Crustal Thickness From 3‐D Gravity Inversion

Lebedeva‐Ivanova

Gaina

Minakov

et al. 2019

Geochem Geophys Geosyst

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The ArcCRUST model consists of crustal thickness and estimated crustal thinning factors grids for the High Arctic and Circum‐Arctic regions (north of 67°N). This model is derived by using 3‐D forward and inverse gravity modeling. Updated sedimentary thickness grid, an oceanic lithosphere age model together with inferred microcontinent rifting ages, variable crystalline crust and sediment densities, and dynamic topography models constrain this inversion. We use published high‐quality 2‐D seismic crustal‐scale models to create a database of Depths to Seismic Moho (DSM) profiles. To check the quality of the ArcCRUST model, we have performed a statistical analysis of misfits between the ArcCRUST Moho depths and DSM values. Systematic analysis of the misfits within the Arctic sedimentary basins provides information about tectonic processes unaccounted by the assumed model of pure‐shear lithospheric extension. In particular, our model implies a less dense and/or thin mantle lithosphere underneath microcontinents in the deep Arctic Ocean where the ArcCRUST depth to Moho values exceed the DSM. A systematically larger gravity‐derived crustal thickness (~3 km) under the western and northern Greenland Sea points to a hotter upper mantle implied by the seismic tomography models in the North Atlantic.

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“…If we convert this minimum value to units of susceptibility in the local magnetic field, we find the minimum susceptibility required to create an induced field of this magnitude is approximately 0.01 (SI). In contrast, magnetic susceptibilities of 0.04 (SI) have been used by Th ebault et al (2010) to reproduce the global satellite observations, under an induced magnetization assumption, and using a crustal thickness model (e.g., Mooney, 2007) as a starting point in an iterative approach. This value of magnetic susceptibility, 0.04 SI, is successful in modeling more than 95% of the satellite observations without resort to unphysical (negative) magnetic thickness.…”

Section: Citationmentioning

confidence: 99%

Magnetism at Depth: A View from an Ancient Continental Subduction and Collision Zone

McEnroe

Robinson

Church

et al. 2018

Geochem Geophys Geosyst

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Recent sophisticated global data compilations and magnetic surveys have been used to investigate the nature of magnetization in the lower crust and upper mantle. Two approaches to constraining magnetizations are developed, providing minimum (0.01 SI) and maximum (0.04 SI) susceptibility estimates, given some assumed thickness (15+ km here). These values are higher than are found in many continental rocks. Are there rocks deeper in the crust or upper mantle that are more magnetic than expected, or are the model assumptions incomplete? What is the magnetic behavior of deep‐crustal and upper mantle rocks, when slightly cooler than the Curie or Néel temperatures of their magnetic minerals, after being exhumed from locations of high‐grade metamorphism at greater depth? Different sets of equilibrium metamorphic minerals can be considered that would form under different conditions. Results on 1,501 samples from the Western Gneiss Region (WGR) Norway, mainly from mafic and ultramafic bodies subducted to depths of 60–200 km and temperatures of 750 up to 950°C at the very highest pressures, show that rocks did not fully equilibrate to the dominant metamorphic‐facies conditions. There is a large variation in petrophysical properties, oxide minerals, and mineral assemblages in WGR samples, though they cannot explain the broad high‐amplitude (deep‐seated) anomalies measured in this region. The presence of magnetite, and exsolved titanohematite and hemoilmenite in samples, shows those magnetic phases are preserved even at eclogite‐facies conditions, in part because complete eclogite‐facies equilibrium was rarely achieved.

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Crust and Lithospheric Structure - Global Crustal Structure

Cited by 41 publications

References 750 publications

Seismic properties and anisotropy of the continental crust: Predictions based on mineral texture and rock microstructure

Seismic properties and anisotropy of the continental crust: Predictions based on mineral texture and rock microstructure

ArcCRUST: Arctic Crustal Thickness From 3‐D Gravity Inversion

Magnetism at Depth: A View from an Ancient Continental Subduction and Collision Zone

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