MAGSAT magnetic anomalies over Antarctica and the surrounding oceans

Ritzwoller, M. H.; Bentley, Charles R.

doi:10.1029/gl009i004p00285

Cited by 25 publications

(11 citation statements)

References 15 publications

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“…These authors produced maps from data reduced using the same order 13 model as did Langel et al [1982aLangel et al [ , 1982b, made selections of data to minimize the effect of external currents, and also performed further linear or quadratic reductions of the data along flight lines. However, their revised diagram [Ritzwoller and Bentley, 1983] smooths out many of these striations, and the cell structures are comparable to those in Figure 4. uncorrected variations along the flight paths used in its construction.…”

Section: The Presence Of Field-aligned and E Layer Ionospheric Currenmentioning

confidence: 68%

“…We were thus surprised to find that most of the structures depicted in the plots in this paper agree well with those determined by Coles et al [1982] and Taylor [1983] in the north and by Bentley [1982, 1983] over Antarctica. Ritzwoller and Bentley [ 1982] appears to suffer from numerous. Ritzwoller and Bentley [ 1982] appears to suffer from numerous.…”

Section: The Presence Of Field-aligned and E Layer Ionospheric Currenmentioning

confidence: 99%

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Small‐scale features in the Earth's magnetic field observed by Magsat

Cain¹,

Schmitz²,

Muth³

1984

J. Geophys. Res.

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A spherical harmonic expansion to degree and order 29 is derived using a selected magnetically quiet sample of Magsat data. Global maps representing the contribution due to terms of the expansion above n = 13 at 400 km altitude are compared with previously published residual anomaly maps and shown to be similar, even in polar regions. An expansion with such a high degree and order displays all but the sharpest features seen by the satellite and gives a more consistent picture of the high‐order field structure at a constant altitude than do component maps derived independently. The appendix is available with the entire article on microfiche. Order from American Geophysical Union, 2000 Florida Avenue, N.W., Washington, DC 20009. Document B83‐008; $2.50. Payment must accompany order.

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Section: The Presence Of Field-aligned and E Layer Ionospheric Currenmentioning

confidence: 68%

Section: The Presence Of Field-aligned and E Layer Ionospheric Currenmentioning

confidence: 99%

Small‐scale features in the Earth's magnetic field observed by Magsat

Cain¹,

Schmitz²,

Muth³

1984

J. Geophys. Res.

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“…None of these diagrams suffer from "flight line" anomalies as were apparent in the early Magsat reductions (e.g. RITZWOLLER and BENTLEY, 1982).…”

Section: Resulting Modelsmentioning

confidence: 99%

“…SAILOR et al, 1982) point to a repeatability of the data which should correspond to at least n*=56. We can plot some maps of components by "band passing" using portions of the spherical harmonic series to compare the detail shown.…”

Section: Resulting Modelsmentioning

confidence: 99%

Numerical experiments in geomagnetic modeling.

Cain

Holter

Sandee

1990

J. geomagn. geoelec

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Numerical tests were made, using least squares fitting of a spherical harmonic model, to a selection of Magsat data to determine the practical limits of this technique with modern computers. The resulting (M102189) model, whose coefficients were adjusted up to n=50, was compared with M07AV6, a previous model which used least squares (on vector data) for coefficients up to n=29, and Gauss-Legendre quadrature (on Z residuals) to adjust the coefficients up to n=63. For the new least squares adjustment to n=50 a condition number of 115 was obtained for the solution matrix, with a resulting precision of 11 significant figures. The M102189 model shows a lower and more Gaussian residual distribution than did M07AV6, though the Gaussian envelope fits to the residual distributions, even for the scalar field, gives "standard deviations" never lower than 6 nT, a factor of three higher than the estimated Magsat observational errors. Ionospheric currents are noted to have a significant effect on the coefficients of the internal potential functions.

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“…Detailed gravity and radio echo ice-sounding surveys have located an ice-covered contact in the vicinity of Dufek Massif [England and Nelson, 1977]. The high regional magnetic anomaly over the Pensacola Mountains recorded from MAGSAT satellite data [Ritzwoller and Bentley, 1982 Paleomagnetic studies [Griffin, 1969;Beck, 1972;Beck and Griffin, 1971;Beck et al, 1968Beck et al, , 1979Burmester and Sheriff, 1980;Burmester and Beck, 1981] show a paleomagnetic pole position similar to that of the Jurassic Ferrar Group, and the presence in some cumulate layers of field reversals that seem to be reflected in the linear pattern of mixed negative and positive aeromagnetic intensities in some areas.…”

Section: Geophysical Studiesmentioning

confidence: 99%

The Dufek intrusion of Antarctica

Ford¹

1990

Mineral Resources Potential of Antarctica

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The mostly ice-covered, stratiform mafic Dufek intrusion of the northern Pensacola Mountains occupies an area of more than 50,000 km 2 and has an interpreted thickness of 8-9 km. It is thus one of the world' s largest igneous bodies of this type. It has many petrologic similarities with resource-rich intrusions such as the Bushveld Complex (South Africa) and the Stillwater Complex (Montana), but its potential for resources is poorly known. The occurrence in the Dufek intrusion of magmatic ore deposits similar to those of other layered mafic intrusions seems likely. Among possible resources, platinum group elements (PGE) would have greatest economic feasibility for exploitation. The Dufek intrusion is of Jurassic age and coeval with Ferrar magmatism of the Transantarctic Mountains. It was emplaced within a multiple-deformed mobile belt of Triassic and older age adjoining the craton of East Antarctica. Cumulates of earliest origin, presumably in part ultramafic, and those of a 2-to 3-km-thick intermediate interval are not exposed. Mafic cumulates of nearly 2-km-thick exposed sections in Dufek Massif and stratigraphically higher in the Forfestal Range show chemical and mineralogic differentiation trends of Fe enrichment comparable to those of other major stratiform intrusions. Sulfide minerals are markedly more abundant in the higher part of the intrusion, where highest PGE abundances are found. However, a possible comparison with the Bus hveld's PGE-rich Merensky Reef suggests greatest resource potential in the Dufek's concealed basal section, which requires drilling for evaluation.

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MAGSAT magnetic anomalies over Antarctica and the surrounding oceans

Cited by 25 publications

References 15 publications

Small‐scale features in the Earth's magnetic field observed by Magsat

Small‐scale features in the Earth's magnetic field observed by Magsat

Numerical experiments in geomagnetic modeling.

The Dufek intrusion of Antarctica

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