Curie isotherm map of Indian subcontinent from satellite and aeromagnetic data

Rajaram, Mita; Anand, S.; Hemant, Kumar; Purucker, Michael E.

doi:10.1016/j.epsl.2009.02.013

Cited by 70 publications

(41 citation statements)

References 33 publications

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“…Bouligand et al 2009), or in terms of heat flow anomalies (e.g. Rajaram et al 2009) remain legitimate. Statistically, however, the observational power spectrum can be represented by a simple model of three parameters such as the mean magnetization, the mean magnetic crustal thickness, and a single power law index for the susceptibility power spectrum.…”

Section: Discussion a N D C O N C L U S I O N Smentioning

confidence: 99%

A statistical spatial power spectrum of the Earth's lithospheric magnetic field

Thébault¹,

Vervelidou

2015

Geophysical Journal International

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S U M M A R YThe magnetic field of the Earth's lithosphere arises from rock magnetization contrasts that were shaped over geological times. The field can be described mathematically in spherical harmonics or with distributions of magnetization. We exploit this dual representation and assume that the lithospheric field is induced by spatially varying susceptibility values within a shell of constant thickness. By introducing a statistical assumption about the power spectrum of the susceptibility, we then derive a statistical expression for the spatial power spectrum of the crustal magnetic field for the spatial scales ranging from 60 to 2500 km. This expression depends on the mean induced magnetization, the thickness of the shell, and a power law exponent for the power spectrum of the susceptibility. We test the relevance of this form with a misfit analysis to the observational NGDC-720 lithospheric magnetic field model power spectrum. This allows us to estimate a mean global apparent induced magnetization value between 0.3 and 0.6 A m −1 , a mean magnetic crustal thickness value between 23 and 30 km, and a root mean square for the field value between 190 and 205 nT at 95 per cent. These estimates are in good agreement with independent models of the crustal magnetization and of the seismic crustal thickness. We carry out the same analysis in the continental and oceanic domains separately. We complement the misfit analyses with a Kolmogorov-Smirnov goodness-of-fit test and we conclude that the observed power spectrum can be each time a sample of the statistical one.

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Section: Discussion a N D C O N C L U S I O N Smentioning

confidence: 99%

A statistical spatial power spectrum of the Earth's lithospheric magnetic field

Thébault¹,

Vervelidou

2015

Geophysical Journal International

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“…Considering that in volcanically active regions around the world earthquake swarms associated with contemporaneous crustal deformation are often inferred to be the result of subsurface magma movements (Wright et al 1976), we propose that the seismic activities could be as a result of movement of, or within, magmatic intrusions in this zone which could also contribute to the low CPD obtained at the Ikogosi Warm Spring region. A thick magnetic crust suggests stable continental regions while thin magnetic crust accounts for tectonically active regions also associated with higher heat flow (Rajaram et al 2009). …”

Section: Discussionmentioning

confidence: 99%

Spectral analysis of aeromagnetic data for geothermal energy investigation of Ikogosi Warm Spring - Ekiti State, southwestern Nigeria

et al. 2014

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Background: Aeromagnetic data of the Ikogosi warm spring region was used to calculate the basal depth of the magnetic layer (Curie point depth) in the region. The warm spring issues from a crossing of fractures from a metasedimentary suite of Effon Psammite formation which form part of the Precambrian basement complex in Nigeria. Method: The adopted computational method transforms the spatial data into the frequency domain and provides a relationship between radially average power spectrum of the magnetic anomalies and the depths to the respective sources. Heat flow density and equivalent depth extent of heat production from radioactive isotopes in the area were also evaluated. Results: The average Curie point depth for the Ikogosi warm spring area is 15.1 ± 0.6 km and centres on the host quartzite rock unit. The computed equivalent depth extent of heat production provides a depth value (14.5 km) which falls within the Curie point depth margin and could indicate change in mineralogy. The low Curie point depth observed at the warm spring source is attributed to magmatic intrusions at depth. This is also evident from the visible older granite intrusion at Ikere -Ado-Ekiti area, with shallow Curie depths (12.37 ± 0.73 km). Conclusions: Results indicate that the area is promising for further geothermal explorations.

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“…The magnetic anomaly data used in this study is based on the Earth Magnetic Anomaly Grid [33][34], which is a 3 arc-minute resolution data set compiled from satellite, ship and airborne magnetic measurements. Comparison between the CPD estimated from the satellite magnetic data and the CPD estimated from the aeromagnetic data show that they are comparable [9,[35][36]37]. The total intensity anomaly is 5 km above WGS84 ellipsoid.…”

Section: Methodsmentioning

confidence: 78%

Curie Point Depth from Spectral Analysis of Magnetic Data in the Southeast Tibet

Yang¹

2017

EARTH

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Abstract:The satellite magnetic anomalies are used to calculate the Curie point depth of the Southeast Tibet by spectral analysis method in the study. The relationship between the Curie point depth and the regional faults or heat flow will be discussed. The results show that the Curie point depth of the study area ranges from 15 km to 36 km and the average depth is 26.3 km. The Curie point depth is cluster-like on the north of the Ailaoshan-Red River Fault, while it is strip-like distribution on the north side. The Curie point depth in the Xiaojiang Fault zone, the Xiaojinhe Fault zone, the Dien Bien Phu Fault zone and the Gaoligong Fault zone are shallow. It could be related to their strong frictional heat induced by these faults. The Curie point depth in the middle Sukhothai Block is shallow, which it is not only related to the Phayao Fault, the Mae Chan Fault and the Nam Ma Fault, but also to the subduction of the Palaeo-Tethys into the Indochina Block. There is a negative but nonlinearly correlation between the heat flow and the Curie point depth in this study area. The areas of low heat flow value correspond to the areas of deep Curie point depth. However, both the high and low heat flow values can be found in the areas of shallow Curie point depth. The possible reason is thought to be related to the low thermal conductivity of the rock.

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Curie isotherm map of Indian subcontinent from satellite and aeromagnetic data

Cited by 70 publications

References 33 publications

A statistical spatial power spectrum of the Earth's lithospheric magnetic field

A statistical spatial power spectrum of the Earth's lithospheric magnetic field

Spectral analysis of aeromagnetic data for geothermal energy investigation of Ikogosi Warm Spring - Ekiti State, southwestern Nigeria

Curie Point Depth from Spectral Analysis of Magnetic Data in the Southeast Tibet

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