A spectral approach to moho depths estimation from gravity measurements in Epirus (NW Greece).

Tselentis, G‐Akis; Drakopoulos, J.; Dimitriadis, Klisthenis

doi:10.4294/jpe1952.36.255

Cited by 47 publications

(19 citation statements)

References 20 publications

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“…Breaks in the slope of the power spectrum curve represent density discontinuities [Gomez-Ortiz et al, 2005]. The linear segment at the lower frequencies is assumed to be related to the Moho depth since the crust/mantle boundary represents a major density interface [Tselentis et al, 1988] since the maximum depth of the estimated density interface is directly related to the dimension of the subregion used in the investigation (~120 × 120 km in this case).…”

Section: Moho Depthmentioning

confidence: 76%

“…We used the 2‐D radially averaged power spectral analysis developed by Tselentis et al . [] for the estimation of the thickness of the crust beneath the ORZ and the surroundings. This method has been widely used for both magnetic and gravity data [ Tselentis et al ., ; Maus and Dimri , ; Maden , ; Hussein et al ., ].…”

Section: Methodsmentioning

confidence: 99%

“…We used the 2-D radially averaged power spectral analysis developed by Tselentis et al [1988] for the estimation of the thickness of the crust beneath the ORZ and the surroundings. This method has been widely used for both magnetic and gravity data [Tselentis et al, 1988;Maus and Dimri, 1996;Maden, 2010;Hussein et al, 2013]. To apply the 2-D radial-power spectrum method, a regional gravity field consisting of a first-order polynomial surface was removed from the Bouguer gravity data to produce a residual gravity anomaly.…”

Section: Moho Depthmentioning

confidence: 99%

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Thermal perturbations beneath the incipient Okavango Rift Zone, northwest Botswana

et al. 2015

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We used aeromagnetic and gravity data to investigate the thermal structure beneath the incipient Okavango Rift Zone (ORZ) in northwestern Botswana in order to understand its role in strain localization during rift initiation. We used three-dimensional (3-D) inversion of aeromagnetic data to estimate the Curie Point Depth (CPD) and heat flow under the rift and surrounding basement. We also used two-dimensional (2-D) power-density spectrum analysis of gravity data to estimate the Moho depth. Our results reveal shallow CPD values (8-15 km) and high heat flow (60-90 mW m À2 ) beneath a~60 km wide NE-trending zone coincident with major rift-related border faults and the boundary between Proterozoic orogenic belts. This is accompanied by thin crust (<30 km) in the northeastern and southwestern parts of the ORZ. Within the Precambrian basement areas, the CPD values are deeper (16-30 km) and the heat flow estimates are lower (30-50 mW m À2 ), corresponding to thicker crust (~40-50 km). We interpret the thermal structure under the ORZ as due to upward migration of hot mantle fluids through the lithospheric column that utilized the presence of Precambrian lithospheric shear zones as conduits. These fluids weaken the crust, enhancing rift nucleation. Our interpretation is supported by 2-D forward modeling of gravity data suggesting the presence of a wedge of altered lithospheric mantle centered beneath the ORZ. If our interpretation is correct, it may result in a potential paradigm shift in which strain localization at continental rift initiation could be achieved through fluid-assisted lithospheric weakening without asthenospheric involvement.

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Section: Moho Depthmentioning

confidence: 76%

Section: Methodsmentioning

confidence: 99%

Section: Moho Depthmentioning

confidence: 99%

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Thermal perturbations beneath the incipient Okavango Rift Zone, northwest Botswana

et al. 2015

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“…The spectral curves were constructed by plotting “ln (Power Spectrum)” against the “wave number (k)” (Figures a and b). The depth to differing gravity anomalies representing boundaries of significant density contrast in the subsurface such as the Moho and the LAB can be estimated by fitting straight lines through linear segments of the spectral curve (Tselentis et al, ). Linear segments of the spectral curve that correspond to lower wave numbers represent deeper density contrast boundaries and higher wave number segments represent shallower density contrast boundaries (Gomez‐Ortiz et al, ; Tselentis et al, ).…”

Section: Gravity Data Methods and Resultsmentioning

confidence: 99%

Lithospheric Controls on the Rifting of the Tanzanian Craton at the Eyasi Basin, Eastern Branch of the East African Rift System

et al. 2018

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Continental rifts most often nucleate within orogenic belts. However, some studies in the East African rift system have shown that continental rifts can also develop within cratons. This work investigated the ~1.5‐Ma Eyasi basin, which propagates in a WSW direction into the Tanzanian craton. The basin is located where the eastern branch of the East African rift system transitions from a narrow rift (~70 km wide) to the wider (~300 km wide) North Tanzanian Divergence. Unlike the rest of the eastern branch segments, the Eyasi basin does not follow the Mozambique orogenic belt located on the eastern margin of the Tanzanian craton. This work generated lithospheric‐scale sections across the basin using (1) digital elevation model to map surface rift‐related brittle structures; (2) aeromagnetic data to determine the depth to the Precambrian basement; and (3) World Gravity Model 2012 to estimate crustal and lithospheric thickness by applying the two‐dimensional radially averaged power spectral analysis and two‐dimensional forward gravity modeling. These cross sections show that the Eyasi basin nucleates within a previously unidentified suture zone within the Tanzanian craton and that this suture zone is characterized by thinner lithosphere that can be as thin as ~95 km. This zone of thinner lithosphere is offset southeastward from the surface expression of the Eyasi basin and might have facilitated the formation of other basins further south. Furthermore, the lithospheric thickness map indicates that the Tanzanian craton is heterogeneous and possibly composed of multiple smaller cratonic fragments.

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“…Due to the two-dimensional character of the dataset, radial averaging of the power spectrum was performed to obtain a onedimensional representation [39][40][41][42][43]. Confidence limits for the depth estimations were calculated from the standard errors of the slopes of the best fitting lines for the linear segments.…”

Section: Power Spectral Analysismentioning

confidence: 99%

New Bouguer Gravity Maps of Venezuela: Representation and Analysis of Free-Air and Bouguer Anomalies with Emphasis on Spectral Analyses and Elastic Thickness

Sanchez-Rojas

2012

International Journal of Geophysics

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A new gravity data compilation for Venezuela was processed and homogenized. Gravity was measured in reference to the International Gravity Standardization Net 1971, and the complete Bouguer anomaly was calculated by using the Geodetic Reference System 1980 and 2.67 Mg/m 3 . A regional gravity map was computed by removing wavelengths higher than 200 km from the Bouguer anomaly. After the anomaly separation, regional and residual Bouguer gravity fields were then critically discussed in term of the regional tectonic features. Results were compared with the previous geological and tectonic information obtained from former studies. Gravity and topography data in the spectral domain were used to examine the elastic thickness and depths of the structures of the causative measured anomaly. According to the power spectrum analysis results of the gravity data, the averaged Moho depths for the massif, plains, and mountainous areas in Venezuela are 42, 35, and 40 km, respectively. The averaged admittance function computed from the topography and Free-Air anomaly profiles across Mérida Andes showed a good fit for a regional compensation model with an effective elastic thickness of 15 km.

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A spectral approach to moho depths estimation from gravity measurements in Epirus (NW Greece).

Cited by 47 publications

References 20 publications

Thermal perturbations beneath the incipient Okavango Rift Zone, northwest Botswana

Thermal perturbations beneath the incipient Okavango Rift Zone, northwest Botswana

Lithospheric Controls on the Rifting of the Tanzanian Craton at the Eyasi Basin, Eastern Branch of the East African Rift System

New Bouguer Gravity Maps of Venezuela: Representation and Analysis of Free-Air and Bouguer Anomalies with Emphasis on Spectral Analyses and Elastic Thickness

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