Potential field tilt—a new concept for location of potential field sources

Miller, Hugh G.; Singh, Vijay

doi:10.1016/0926-9851(94)90022-1

Cited by 1,118 publications

(513 citation statements)

References 5 publications

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“…Filtering and derivative calculations, especially the normalised tilt-derivative filtering (TDR) (Fig. 3;Miller & Singh, 1994;Verduzco et al, 2004), helped to define different basement domains, subvertical geological boundaries, faults and dykes that are discussed in this paper. The TDR filter increased the amplitude of the magnetic total field anomalies and provided an effective alternative to the vertical derivative to map the continuity of the dykes that crop out only very locally in the terrain (Fig.…”

Section: New High-resolution Aeromagnetic Datamentioning

confidence: 99%

Multiphase mafic dykes in the Caledonides of northern Finnmark revealed by a new high-resolution aeromagnetic dataset

Nasuti¹,

Roberts²,

Gernigon³

2015

NJG

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New high-resolution aeromagnetic data from northern Finnmark provide confirmatory evidence for the existence of both metadolerite and unmetamorphosed dolerite dykes transecting the Caledonian nappes and subjacent (par)autochthonous lithostratigraphical successions from Magerøya in the west to Varanger Peninsula in the east. Three ages of mafic dykes are known from isotopic dating studies -Ediacaran, Late Devonian and Early Carboniferous -but actual dyke outcrop in the case of the two younger dyke sets is very limited. High-amplitude magnetic responses in two thrust sheets in northwestern Varanger Peninsula, north of the TKFZ and beneath the Tanahorn Nappe, are clearly shown to relate to swarms of Ediacaran metadolerite dykes. Individual dykes discontinuously exposed on the surface can be followed as linear positive magnetic anomalies over distances of 25 km inland. Their extent offshore is not discussed here because it is beyond our data coverage in this paper. In eastern Varanger Peninsula, 8-9 dolerite dykes of Late Devonian age occur in discontinuous or limited outcrop. The new aeromagnetic data show, however, that up to 20 such dykes can be identified in the subsurface in the region between Vardø and Syltefjorden based on their linear positive magnetic anomaly signatures. South of the TKFZ, two Late Devonian dolerite dykes, well known from small coastal outcrops, are clearly visible as linear positive magnetic anomalies both on land and offshore beneath the sea-floor of Varangerfjorden. The most spectacular manifestations of what we consider to represent blind dolerite dykes are seen in connection with linear positive magnetic anomalies relating to Early Carboniferous dolerite dykes exposed on Magerøya and western Digermul Peninsula. These prominent linear anomalies follow many of the mapped NW-SE-to WNW-ESE-trending faults that have disrupted the Caledonian nappes in this part of Finnmark, and some are continuous over distances of more than 100 km from Magerøya to western Varanger Peninsula. These particular dykes and faults have been interpreted as relating to a major period of extension and rifting that occurred in the SW Barents Sea and adjacent onshore areas of Norway in Carboniferous time.

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Section: New High-resolution Aeromagnetic Datamentioning

confidence: 99%

Multiphase mafic dykes in the Caledonides of northern Finnmark revealed by a new high-resolution aeromagnetic dataset

Nasuti¹,

Roberts²,

Gernigon³

2015

NJG

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show abstract

“…Filtering and derivative calculations, especially the normalised tilt-derivative filtering (TDR) (Miller & Singh, 1994;Verduzco et al, 2004), helped to define different basement domains, subvertical geological boundaries, faults and dykes (Fig. 4B).…”

Section: Aeromagnetic Datamentioning

confidence: 99%

New high-resolution aeromagnetic and radiometric surveys in Finnmark and North Troms: linking anomaly patterns to bedrock geology and structure

Nasuti¹,

Roberts²,

Dumais³

et al. 2016

NJG

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New high-resolution aeromagnetic data from the Caledonides and Archaean-Palaeoproterozoic crystalline basement of Finnmark and North Troms derived from surveys conducted as part of NGU's MINN programme provide spectacular and confirmatory evidence for the continuation of diverse, Precambrian greenstone belts and granulite terranes beneath the magnetically transparent Caledonian nappes. Complementary airborne radiometric data collected in the same survey contribute to the analytical process and to an evaluation of the mineral potential in the area. Some parts of existing data have also been reprocessed using new techniques and software to reach the same level as the newly acquired data. The new compiled data provide images of the magnetic field at sufficiently high resolution to allow us to examine finer details of the bedrock geology. One of the principal outcomes of the analysis is a picture of the detailed structural fabric of the region provided by images of tilt derivatives of the magnetic field that enhance anomalies. This fabric is an important framework for developing exploration strategies. Patterns and other characteristics of the magnetic field have been used to revise positions of some geological boundaries, especially in poorly exposed areas, and delineate specific domains within northern Norway. Radiometric data have been used to supplement the magnetic interpretations in some cases. In general, there is a good correlation between the radiometric data and magnetic anomaly maps which can be utilised to re-evaluate the geological boundaries. Several such features of interest are discussed. As an example, NW-SE-trending, fault-bounded terranes or belts which extend from Finnmark and Troms through northern Finland, Sweden and Russia can be easily followed on the high-resolution data. In this contribution, all the main geological terranes from the Archaean-Palaeoproterozoic belt to the Caledonian nappes in northern Norway will be discussed in relation to their magnetic patterns and radiometric anomalies.

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“…In recent years several such methods have been described which involve equalising the amplitudes of magnetic anomalies, by normalizing the derivatives of the field. For instances, the tilt derivative (Miller and Singh, 1994;Verduzco et al, 2004), the Theta map (Wijns et al, 2005) and the horizontal tilt derivative (TDX) (Cooper and Cowan, 2006). Recently, de Souza and Ferreira (2012) proposed a simple derivative-based method for qualitative and quantitative interpretation of magnetic anomalies from dykelike structures.…”

Section: Introductionmentioning

confidence: 99%

The application of the Signum transform to the interpretation of magnetic anomalies due to prismatic bodies

Souza

2015

ASEG Extended Abstracts

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Potential field tilt—a new concept for location of potential field sources

Cited by 1,118 publications

References 5 publications

Multiphase mafic dykes in the Caledonides of northern Finnmark revealed by a new high-resolution aeromagnetic dataset

Multiphase mafic dykes in the Caledonides of northern Finnmark revealed by a new high-resolution aeromagnetic dataset

New high-resolution aeromagnetic and radiometric surveys in Finnmark and North Troms: linking anomaly patterns to bedrock geology and structure

The application of the Signum transform to the interpretation of magnetic anomalies due to prismatic bodies

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