remanent magnetism


remanent magnetism
magnetization in minerals induced by a former magnetic field and persisting after the field changes. Cf. paleomagnetism.
[1865-70]

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▪ rocks
also called  Paleomagnetism, or Palaeomagnetism,  

      the permanent magnetism in rocks, resulting from the orientation of the Earth's magnetic field at the time of rock formation in a past geological age. It is the source of information for the paleomagnetic studies of polar wandering and continental drift. Remanent magnetism can derive from several natural processes, generally termed natural remanent magnetism, the most important being thermo-remanent magnetism. This arises when magnetic minerals forming in igneous rocks cool through the Curie point and when the magnetic domains within the individual minerals align themselves with the Earth's magnetic field, thus making a permanent record of its orientation.

      A second mechanism operates when small grains of magnetic minerals settle into a sedimentary matrix, producing detrital remanent magnetism. It is hypothesized that the tiny grains orient themselves in the direction of the Earth's magnetic field during deposition and before the final consolidation of the rock. The magnetism thus introduced appears to persist through later alteration and compaction of the rock, although the details of these processes have not been fully studied.

      Rocks may acquire remanent magnetism in at least two other ways: (1) rocks made up of nonmagnetic minerals may be chemically altered to yield magnetic minerals, and these newly formed minerals will acquire remanent magnetism in the presence of the Earth's magnetic field; and (2) igneous rocks already cooled may ultimately acquire remanent magnetism by a process called viscous magnetization. The difference between these several types of remanent magnetism can be determined, and the magnetic history of a particular rock can therefore be interpreted.

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Universalium. 2010.

Look at other dictionaries:

  • Remanent magnetism — Remanent Rem a*nent, a. [L. remanens, p. pr. of remanere. See {Remain}, and cf. {Remnant}.] Remaining; residual. [1913 Webster] That little hope that is remanent hath its degree according to the infancy or growth of the habit. Jer. Taylor. [1913… …   The Collaborative International Dictionary of English

  • remanent magnetism — liekamasis magnetizmas statusas T sritis fizika atitikmenys: angl. remanent magnetism; residual magnetism vok. remanenter Magnetismus, m rus. остаточная намагниченность, f; остаточный магнетизм, m pranc. magnétisme rémanent, m; magnétisme… …   Fizikos terminų žodynas

  • remanent magnetism — noun : residual magnetism * * * Geol. magnetization in minerals induced by a former magnetic field and persisting after the field changes. Cf. paleomagnetism. [1865 70] …   Useful english dictionary

  • Remanent — Rem a*nent, a. [L. remanens, p. pr. of remanere. See {Remain}, and cf. {Remnant}.] Remaining; residual. [1913 Webster] That little hope that is remanent hath its degree according to the infancy or growth of the habit. Jer. Taylor. [1913 Webster]… …   The Collaborative International Dictionary of English

  • Remanent — * Remanence * Remanent magnetism * Remanent induction * Remanent polarization …   Wikipedia

  • remanent — adjective remaining or persisting especially after an electrical or magnetic influence is removed remanent magnetism, remanent induction, remanent polarization See Also: remain, remainder, remnant …   Wiktionary

  • magnetism — /mag ni tiz euhm/, n. 1. the properties of attraction possessed by magnets; the molecular properties common to magnets. 2. the agency producing magnetic phenomena. 3. the science dealing with magnetic phenomena. 4. strong attractive power or… …   Universalium

  • remanent — [ rɛmənənt] adjective (of magnetism) remaining after the magnetizing field has been removed. Derivatives remanence noun Origin ME: from L. remanent , remanere remain …   English new terms dictionary

  • remanent — adj. 1 remaining, residual. 2 (of magnetism) remaining after the magnetizing field has been removed. Derivatives: remanence n. Etymology: ME f. L remanere REMAIN …   Useful english dictionary

  • residual magnetism — Remanent Rem a*nent, a. [L. remanens, p. pr. of remanere. See {Remain}, and cf. {Remnant}.] Remaining; residual. [1913 Webster] That little hope that is remanent hath its degree according to the infancy or growth of the habit. Jer. Taylor. [1913… …   The Collaborative International Dictionary of English


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