The Stability of NRM of Deccan Traps Basalts in India

Kinoshita, Hajimu; Aoki, Yutaka

doi:10.5636/jgg.24.459

Cited by 4 publications

(2 citation statements)

References 26 publications

(16 reference statements)

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“…These curves bear a strong resemblance to J,-T curves obtained in air on Deccan traps basalts in India (Kinoshita & Aoki 1972), which are of similar age as the Disko basalts. These authors found two contrasting types (' I, I1 ') of magnetic behaviour, resembling our classes n and r, except that their study included samples from flows having stable N polarity as well as from stable4 flows, with each type of behaviour occurring among samples from both stable polarity groups.…”

Section: Therrnornagnetic Measurementssupporting

confidence: 63%

Palaeomagnetism of Late Cretaceous-Tertiary Volcanics from Disko Island, West Greenland

Deutsch

Kristjánsson

1974

Geophys J Int

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Various magnetic properties of three lava profiles (45 flows), basalt breccia and intrusives from the southernmost part of the west Greenland basalt area have been measured. All samples contain a stable remanence component of reverse (R) polarity, in accord with most other rocks of the Brito-Arctic Lower Tertiary province. Three magnetic groupings were found: Class r. In the majority of lava samples, the NRM is dominated by the stable R component, which remains stable in direction under AF cleaning and has a characteristic single, high Curie point (T, = 550-570 "C). Class n. One-quarter of the lava samples had a soft, normal NRM whose polarity switched to R under AF treatment at 50-100 Oe and became stable in higher fields. Class n samples often show both a low T, (G300 "C) and a high T,, and their mean Koenigsberger ratio (0.43) is low compared to class r (2-9). Class r' behaviour, combining r and n features, occurs especially in the breccia, intrusives and remaining lavas. Laboratory viscous build-up tests indicate that the soft component prominent in n and r' rock is a VRM acquired during the present (Brunhes) geomagnetic epoch. Rock of different classes frequently co-exists even in single flows; this is attributed simultaneously to (1) spatial differences in oxygen fugacity during initial cooling, and (2) variations in titanomagnetite domain-size distribution near the singledomain-superparamagnetic threshold. Spatial variations in the rate of lava extrusion and of cooling can explain both effects.One flow has a K-Ar age of 70+4 My. From the magnetic results on 37 flows, it is concluded that the stable remanence is of primary origin and that its between-flow dispersion (19") is due largely to secular variation. The average palaeo-field direction calculated from these flows corresponds to a reverse pole at 62" N, 169" W, with dp = 8", dm = 9". This pole agrees with a published Lower Tertiary pole for east Greenland but is displaced from poles of similar age for north-western Europe. This is compatible with an opening of the Norwegian Sea that occurred mainly after these rocks were laid down.

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Section: Therrnornagnetic Measurementssupporting

confidence: 63%

Palaeomagnetism of Late Cretaceous-Tertiary Volcanics from Disko Island, West Greenland

Deutsch

Kristjánsson

1974

Geophys J Int

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“…The Curie temperatures of these samples range from 440° to 585°C, but most of the Curie temperatures are distributed between 560° and 580°C, showing a predominance of ferromagnetic minerals of nearly pure magnetite composition. The thermomagnetic behavior of the samples shows the most ferromagnetic minerals are more or less oxidized through unmixing process of Ti-rich titanomagnetite to reproduce titanium-poor titanomagnetites (Buddington and Lindsley, 1964;0'Reilly and Banerjee, 1967;Ozima and Larson, 1970;Kinoshita and Aoki, 1972;Nishitani and Kono, 1983).…”

Section: Thermal Analyses and Curie Temperatures (R C )mentioning

confidence: 99%

Magnetic Properties and Alteration in Basalt, Hole 504B, Deep Sea Drilling Project Leg 83

Kinoshita¹,

Furuta²,

Kawahata³

1985

Initial Reports of the Deep Sea Drilling Project

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We report measurements of magnetic intensity, inclination, initial susceptibility, Koenigsberger's ratio, saturation magnetization, and Curie temperatures of 68 basalt samples from the Leg 83 section of Hole 504B. As in the upper part of the hole, reversely magnetized units predominate. Intensities of natural remanent magnetization vary widely, but the range of variation is an order of magnitude less than in the upper part of the hole. This and the other properties measured indicate that the magnetic characteristics of basalts from Hole 504B have been strongly affected by hydrothermal alteration, particularly in the deeper, Leg 83 section. The alteration states of the magnetic samples were studies using Xray diffraction, electron microprobe, X-ray fluorescence, and ion coupled plasma. Our results suggest three alteration zones in Hole 504B: a low-temperature zone (274.5-890 m) and two high-temperature zones (890-1050 m and 1050-1350 m), differing in the number of veins observed in the samples and presumably differing in the volumes of hydrothermal fluids which reacted with the basalts.

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Hamiltonian formalism for Euler parameters

Maciejewski

1985

Celestial Mechanics

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The Stability of NRM of Deccan Traps Basalts in India

Cited by 4 publications

References 26 publications

Palaeomagnetism of Late Cretaceous-Tertiary Volcanics from Disko Island, West Greenland

Palaeomagnetism of Late Cretaceous-Tertiary Volcanics from Disko Island, West Greenland

Magnetic Properties and Alteration in Basalt, Hole 504B, Deep Sea Drilling Project Leg 83

Hamiltonian formalism for Euler parameters

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