Effect of the lithospheric thermal state on the Moho interface: A case study in South America

Bagherbandi, Mohammad; Bai, Yongliang; Sjöberg, Lars E.; Tenzer, Róbert; Majid, Asifa; Miranda, Silvia; Sanchez, Juan Manuel Alcacer

doi:10.1016/j.jsames.2017.02.010

Cited by 6 publications

(4 citation statements)

References 46 publications

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“…In contrast, gravity inversion has the advantage of high coverage in margin areas, and its accuracy has been increased greatly (Smith and Sandwell, 1994;Sandwell et al, 2014). A high-coverage and high-accuracy gravity field can be used to map crustal thickness variations of passive margins, delineate fault distributions and estimate crustal stretching styles on a continental-margin scale constrained by seismic profiles (Wang et al, 2011;Tenzer et al, 2015;Oruç and Sönmez, 2017;Bagherbandi et al, 2017;Bai et al, 2019). Therefore, the gravitational method has unique advantages for comprehensive margin-scale symmetry studies.…”

Section: Introductionmentioning

confidence: 99%

Symmetry of the South China Sea conjugate margins in a rifting, drifting and collision context

Bai

Wang

Dong

et al. 2020

Marine and Petroleum Geology

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The symmetry of conjugate rifted margins is a first-order observable feature reflecting the geodynamic processes acting during and after continental rifting. The symmetry of the South China Sea (SCS) rifted margins can be deduced from comprehensive geophysical datasets on a continental-margin scale. Here, we combine three key approaches: (1) lateral fault distributions are delineated according to free-air gravity anomalies, (2) crustal stretching styles are mapped based on gravity inversion constrained by deep seismic profiles, and (3) total extensions of conjugate margins are estimated according to margin restorations and tectonic settings. We infer a predominantly symmetric rifting style caused by pure shear extension, with only narrow domains of asymmetric deformation in continent-ocean transition (COT) regions that have undergone simple shear and where the lower crust of the highly thinned distal margin is embrittled before continental breakup. However, our analysis also suggests that this symmetry has been modified by post-rift geodynamic processes. Southward lower crustal flow, which occurred only on the southern margin due to the low viscosity of the lower crust and the slab pull induced by the subducting Proto-SCS plate during seafloor spreading, shifted the crustal stretching styles from symmetric to asymmetric. The collision between the southern margin and Borneo thickened the lower crust more than the upper crust at the southern end of the southern margin and shortened the southern margin. This event had a large impact on the SE margin but a small impact on the SW margin. We conclude that (1) for the SE and NE margins, the crustal stretching styles shifted from asymmetric to approximately symmetric, and the total extensions shifted from symmetric to asymmetric; (2) for the SW and NW margins, the crustal stretching and total extensions remained asymmetric and symmetric, respectively.

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Section: Introductionmentioning

confidence: 99%

Symmetry of the South China Sea conjugate margins in a rifting, drifting and collision context

Bai

Wang

Dong

et al. 2020

Marine and Petroleum Geology

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“…Bagherbandi et al [21] discussed the influence of the distribution of sedimentation on the gravity field and even the geometry of the Moho in the SAC. From their research results, we find that marine sedimentation is mainly distributed in the eastern and northern continental margins of the SAC, and continental sedimentation and river sedimentation are also mainly located in the north.…”

Section: Erosion and Sedimentation Effectsmentioning

confidence: 99%

“…At present, many studies have explored the external and internal geoscience issues of the SAC, such as the impact of the subduction of the NZ on the lithospheric erosion of the SAC, the changes of horizontal and vertical surface displacement, the distribution of stress and strain fields in Patagonia and the crustal thickness and Moho depth of the SAC, all of which have obtained satisfactory results. [15][16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

GRACE Data Explore Moho Change Characteristics Beneath the South America Continent near the Chile Triple Junction

Sun

Guo

2022

Remote Sensing

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The internal and external mass migration and redistribution of the Earth system are usually accompanied by changes in the gravity field, and the Gravity Recovery and Climate Experiment (GRACE) has been proven to be able to effectively monitor and evaluate such changes. The Chile Triple Junction (CTJ) is the convergence point of the Nazca plate, the Antarctic plate and the South American plate. Subductions of different forms and rates in the north and south of the CTJ have varying degrees of impact on the surface and underground material changes of the South American plate. In this study, GRACE data are used in the estimation of the comprehensive mass changes in the South America Continent (SAC) Near the CTJ (~15° range). In addition, surface movement changes constrained by GNSS data cannot fully explain the GRACE results after deducting hydrological information, which indicates that residual signals might be attributed to mass changes beneath the crust, that is, the Moho interface deformation. After eliminating surface movement and hydrological signals from the comprehensive mass changes of GRACE, this study obtains the deep structural information and calculates the Moho changes of three significant regions with rates of −2.12 ± 0.67 cm/yr, 0.18 ± 0.19 cm/yr and −6.46 ± 1.31 cm/yr, respectively. Results have demonstrated that the subductions of the Nazca plate and the Antarctica plate have an effect on the uneven deformation of the Moho interface beneath the SAC. The Moho beneath the SAC mainly shows a deepening trend, but it is uplifted in some areas north of CTJ. On the whole, the rate of Moho changes is greater in the south than in the north. The relationship between Moho changes and surface changes also indicates that a longer timescale may be needed for maintaining isostatic balance.

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“…x and y denote the horizontal and vertical coordinates. The lithosphere thickness of the continental plate was set as 100 km, and the thickness of the upper and lower crust was both 20 km (Assumpção et al, 2013;Bagherbandi et al, 2017;Liu et al, 2019). A linear interpolation method was used for the initial temperature field of the continental plate (Li and Shi, 2016).…”

Section: Visco-plastic Rheologymentioning

confidence: 99%

Numerical Simulation of the Effects of Wedge Subduction on the Lithospheric Thermal Structure and the Seismogenic Zone South of Chile Triple Junction

Guo¹,

Sun²,

D³

2021

Front. Earth Sci.

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In contrast to common subduction, the young and thin part of the Antarctic Plate subducts first to the south of the Chile Triple Junction (CTJ), followed by the old and thick part, corresponding to wedge subduction. A finite element model was used to simulate the wedge subduction of the Antarctic Plate and to compare it with the slab subduction of the Nazca Plate. The results show that the CTJ is not only a wedge subduction boundary but also an important factor controlling the lithospheric thermal structure of the overriding plate. The computed heat flow curves are consistent with the data observed near the trench of the two selected profiles. The different slab dips to the north and south of the CTJ are considered to be caused by wedge subduction. When the slabs are young and at the same age, the deep dip of the Antarctic slab is 22° smaller than the Nazca slab. Southward from the CTJ, the slab age of the wedge subduction increases, which leads to a larger slab dip, a colder slab, and a wider seismogenic zone. The effect of the slab age of wedge subduction on the focal depth is smaller than that of the convergence rate. A 4.8-cm/year difference in convergence rate of the wedge subduction results in an 11-km difference in the width of the seismogenic zone and a 10-km difference in the depth of the downdip limit. Among these controlling factors, the convergence rate plays a major role in the different focal depths south and north of the CTJ.

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Effect of the lithospheric thermal state on the Moho interface: A case study in South America

Cited by 6 publications

References 46 publications

Symmetry of the South China Sea conjugate margins in a rifting, drifting and collision context

Symmetry of the South China Sea conjugate margins in a rifting, drifting and collision context

GRACE Data Explore Moho Change Characteristics Beneath the South America Continent near the Chile Triple Junction

Numerical Simulation of the Effects of Wedge Subduction on the Lithospheric Thermal Structure and the Seismogenic Zone South of Chile Triple Junction

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