Crustal magmatism and lithospheric geothermal state of western North America and their implications for a magnetic mantle

Wang, Jian; Li, Chun‐Feng

doi:10.1016/j.tecto.2014.11.002

Cited by 39 publications

(30 citation statements)

References 120 publications

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“…Our solution leads to a high variability in β values (Figure S3). For marine areas such as the Alboran Sea or the oceanic crust present in the Algerian Basin, β needs to be small, between 2.5 and 3 matching the results from previous studies (Li et al, ; Li & Wang, ; Wang & Li, ). For continental areas β varies between 3 and 4 due to the more heterogeneous geological setting of the continental Iberian Peninsula.…”

Section: Methodssupporting

confidence: 55%

“…Li et al () presented a modified centroid method calculation to account for a fractal response of the magnetic layer. This approach has been successfully applied in different scenarios (Bansal et al, ; Li et al, ; Li & Wang, ; Wang & Li, ) to model the depth to the bottom of the magnetic layer as follows,

ln ([], {|k|}^{((), β - 1) / 2} \times A_{normalΔ T} ((), |k|)) = ln B - (||, k) Z_{t}

ln ([], {|k|}^{((), β - 1) / 2} \times A_{normalΔ T} ((), |k|) / (||, k)) = ln C - (||, k) Z_{c}

where A Δ T (| k |) is the radially averaged amplitude spectra, Z t is the top of the centroid, Z c is the centroid depth, B and C are constants, and A Δ T (| k |)/| k | is the scaled amplitude spectrum.…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, and for the sake of resolution, we have adopted two different window sizes, 150 × 150 km 2 and 200 × 200 km 2 , with a shift between windows of 50 and 66.66 km, respectively. We have calculated a total of 940 windows and taken the averaged CPD, derived from the two window sizes selected, as our final solution as done by Wang and Li ().…”

Section: Methodsmentioning

confidence: 99%

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Curie Point Depth of the Iberian Peninsula and Surrounding Margins. A Thermal and Tectonic Perspective of its Evolution

et al. 2018

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In this work the thermal structure of the Iberian Peninsula is derived from magnetic data by calculating the bottom of the magnetization, assumed to be the Curie‐point depth (CPD) isotherm, which accounts for the depth at which magnetite becomes paramagnetic (580°C). Comparison of the CPD with crustal thickness maps along with a heat flow map derived from the CPD provides new insights on the lithospheric thermal regime. Within Iberia, the CPD isotherm has thickness in the range of 17 to 29 km. This isotherm is shallow (<18 km) offshore, where the lithosphere is thinner. In continental Iberia, the NW Variscan domain presents a magnetic response that is most probably linked to thickening and later extension processes during the late Variscan Orogeny, which resulted in widespread crustal melting and emplacement of granites (in the Central Iberian Arc). The signature of the CPD at the Gibraltar Arc reveals a geometry consistent with the slab roll‐back geodynamic model that shaped the western Mediterranean. In offshore areas, a broad extension of magnetized upper mantle is found. Serpentinization of the upper mantle, probably triggered in an extensional context, is proposed to account for the magnetic signal. The Atlantic margin presents up to 8 km of serpentinites, which, according to the identification of exhumed mantle, correlates with a hyperextended margin. The Mediterranean also presents generalized serpentinization up to 6 km in the Algerian Basin. Furthermore, a heat flow map and a Moho temperature map derived from the CPD are presented.

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Section: Methodssupporting

confidence: 55%

ln ([], {|k|}^{((), β - 1) / 2} \times A_{normalΔ T} ((), |k|)) = ln B - (||, k) Z_{t}

ln ([], {|k|}^{((), β - 1) / 2} \times A_{normalΔ T} ((), |k|) / (||, k)) = ln C - (||, k) Z_{c}

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Curie Point Depth of the Iberian Peninsula and Surrounding Margins. A Thermal and Tectonic Perspective of its Evolution

et al. 2018

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“…TC-Tengchong block, BS-Baoshan block, SM-Simao Block, MY-Middle Yunnan Block, EY-Eastern Yunnan Block, SC-South China Block. F 1 -Nujiang Fault, F 2 -Lancangjiang Fault, F 3 -Lijiang-Xiaojinhe Fault, F 4 -Red River Fault, F 5 -Xiaojiang Fault, F 6 -Kangding-Yiliang-Shuicheng Fault, F 7 -Mile-Shizong-Shuicheng Fault fault zones divide the tectonic units of the Yunnan area into the Tengchong block, Baoshan block, Simao block, Middle Yunnan block, and Eastern Yunnan block (Bai et al 2010;Wang and Li 2015;Wen et al 2017).…”

Section: Research Backgroundmentioning

confidence: 99%

Studies on the relationships of the Curie surface with heat flow and crustal structures in Yunnan Province, China, and its adjacent areas

Liu

Kang

Chen

et al. 2019

Earth Planets Space

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A Curie surface indicates the distribution of the thermal fields underground, providing a clear marker for the thermodynamic effect in the crust and mantle. In this paper, based on a geomagnetic field model (NGDC-720) and aeromagnetic data, we use power spectrum analysis of magnetic anomalies to estimate the Curie surface in Yunnan Province, China, and its adjacent areas. By combining the distribution of the Curie surface with regional heat flow, the geothermal gradient, crustal wave velocity ratio anomalies, high-conductivity layer anomalies, and the Moho surface, we reveal the connection between the undulation of the magnetic basement and the crustal structures. The results indicate that the uplift and depression of the Curie surface in the research area are distinct. The Curie surface is approximately inversely correlated to the surface heat flow. The Lijiang-Jianchuan-Baoshan-Tengchong and Jianchuan-Chuxiong-Kunming-Yuxi zones are two Curie surface uplift zones, and their crust-mantle heat flows are relatively high. The Curie surface uplift zone along the Lijiang-Xiaojinhe fault and Red River fault is consistent with the heading direction of the fault zone and is partially in agreement with the eastward mass flow of the Tibetan Plateau. The Curie surface uplift zone is consistent with the high wave velocity ratio and high-conductivity layer anomaly region of the crust. The depth of the Curie surface is less than the depth of the Moho surface.

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“…Since the wavenumber content of magnetic anomaly data varies spatially, and the long‐wavelength anomalies require large windows that reduce the spatial resolution, spatio‐spectral localization techniques are necessary. Most commonly, the Curie depth is estimated within square windows of various sizes that are moved across the study region to produce a map (e.g., Bouligand et al, ; Li et al, ; Wang & Li, ; Witter & Miller, ). The segmentation of the signal using moving windows has significant drawbacks including spectral leakage and bias.…”

Section: Introduction and Tectonic Settingmentioning

confidence: 99%

Mapping Curie Depth Across Western Canada From a Wavelet Analysis of Magnetic Anomaly Data

2019

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In western Canada, geophysical studies infer an abrupt change in crustal temperatures between the Canadian Cordillera and the adjacent North American craton, with important implications for the tectonics and geodynamics of the area. We use a wavelet analysis of magnetic anomaly data in western Canada to map the depth to the bottom of the magnetic source, or Curie depth. This depth corresponds to the point at which crustal rocks reach their Curie temperature, thus providing an estimate of geothermal gradient. Our model is defined by a fractal distribution of magnetization characterized by the parameter β, as well as the depths to the top (z t ) and bottom (z b ) of the magnetized layer. Synthetic tests reveal the increased accuracy of the estimated z b when values for z t and β are fixed prior to the inversion. We set z t to the thickness of sedimentary rocks overlying the magnetic bedrock and use various values of β to estimate z b . We determine β a posteriori by comparing Monte Carlo simulations of predicted heat flow values (assuming a Curie temperature of 580°C) with observed heat flow in various regions. Our results suggest a β value of 2.5 for the Canadian Cordillera and Slave craton, and 2 for the remaining North American craton. The Curie depths resolve geological domains and important structural features, with estimates for z b averaging 15 ± 1 km in the Cordillera, 32 ± 3 km in the Slave craton, and 34 ± 3 km in the North American craton to the south.Plain Language Summary Despite a relatively high elevation, geophysical imaging of the Earth beneath Canada's western mountains reveals a distinct 150 km thinning of the tectonic plates. The plates define the rigid outer shell of the Earth, and the thickness change is coincident with a topographic difference (higher) at the surface and a temperature difference (hotter) at depth. The relationship between the high topography with the thinner tectonic plate and hotter material at depth is not well understood. The objective of this research is to estimate temperatures of the Earth's crust below the surface in western Canada using the magnetic properties of rocks. At a certain temperature, rocks lose their magnetization and therefore do not produce magnetic anomalies. By analyzing magnetic anomaly data, we can infer the depth at which this temperature is achieved, which provides estimates of the thermal gradient in the crust. Combining these estimates with heat flow measurements provides more accurate constraints on the physical properties of the tectonic plate and will allow different tectonic models to be evaluated, allowing for a better understanding of the mechanical behavior of the Canadian Cordillera.

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Crustal magmatism and lithospheric geothermal state of western North America and their implications for a magnetic mantle

Cited by 39 publications

References 120 publications

Curie Point Depth of the Iberian Peninsula and Surrounding Margins. A Thermal and Tectonic Perspective of its Evolution

Curie Point Depth of the Iberian Peninsula and Surrounding Margins. A Thermal and Tectonic Perspective of its Evolution

Studies on the relationships of the Curie surface with heat flow and crustal structures in Yunnan Province, China, and its adjacent areas

Mapping Curie Depth Across Western Canada From a Wavelet Analysis of Magnetic Anomaly Data

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