Magnetic remanence in the Murchison meteorite

Kletetschka, Günther; Kohout, T.; Wasilewski, P. J.

doi:10.1111/j.1945-5100.2003.tb00275.x

Cited by 47 publications

(43 citation statements)

References 25 publications

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“…Murchison was also found to be much less resistant to thermal demagnetization analyses to 150°C than Allende or Orgueil (Banerjee and Hargraves 1972). Zero-field cycling of these magnetite-rich meteorites to 77 K leads to large changes in NRM intensity (Brecher and Arrhenius 1974;Kletetschka et al 2003) (with whole rock samples from Karoonda demagnetized by 95%), indicating that Karoonda, Orgueil, and Murchison are highly susceptible to remagnetization and demagnetization effects from thermal cycling in space through magnetite's Verwey transition (see Sect. 2.4).…”

Section: Carbonaceous Chondritesmentioning

confidence: 92%

Paleomagnetic Records of Meteorites and Early Planetesimal Differentiation

et al. 2009

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The large-scale compositional structures of planets are primarily established during early global differentiation. Advances in analytical geochemistry, the increasing diversity of extraterrestrial samples, and new paleomagnetic data are driving major changes in our understanding of the nature and timing of these early melting processes. In particular, paleomagnetic studies of chondritic and small-body achondritic meteorites have revealed a diversity of magnetic field records. New, more sensitive and highly automated paleomagnetic instrumentation and an improved understanding of meteorite magnetic properties and the effects of shock, weathering, and other secondary processes are permitting primary and secondary magnetization components to be distinguished with increasing confidence. New constraints on the post-accretional histories of meteorite parent bodies now suggest that, contrary to early expectations, few if any meteorites have been definitively shown to retain records of early solar and protoplanetary nebula magnetic fields. However, recent studies of pristine samples coupled with new theoretical insights into the possibility of dynamo generation on small bodies indicate that some meteorites retain records of internally generated fields. These results indicate that some planetesimals formed metallic cores and early dynamos within just a few million years of solar system formation.

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Section: Carbonaceous Chondritesmentioning

confidence: 92%

Paleomagnetic Records of Meteorites and Early Planetesimal Differentiation

et al. 2009

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“…The efficiency was obtained by taking the ratio of NRM to SIRM, called REM. The REM analytic method had been established initially by Wasilewski (1977), and the method developed further by Kletetschka et al, (2003aKletetschka et al, ( , 2004a. Terrestrial rocks whose NRM contains single components of thermal remanence magnetization (TRM) have the REM values of between 0.01 − 0.02 (Kletetschka et al, 2003a,b).…”

Section: Fig 1 A)mentioning

confidence: 99%

Impact-pressure controlled orientation of shatter cone magnetizations in Sierra Madera, Texas, USA

Adachi

Kletetschka

2008

Stud Geophys Geod

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A suite of Sierra Madera Impact deformed rocks was studied and magnetic analyses were performed. We characterized the magnetic signatures of two locations, sites A and B that have different physical characteristics of shock fractured structures as well as the magnetic signatures. Shatter cone at site A has a fine-scale (few to ~10 mm) distributed array of complete shatter cones with sharp apex. Natural remanent magnetization (NRM) of site A shatter cone is distributed within the plane that is perpendicular to the apexes of the cones. Shatter cone at site B shows no apparent cone shape or apex, instead, a relatively larger scale and multiple striated joint set (MSJS) and sinusoidal continuous peak. NRM of site B shatter cone is clustered along the apexes. The difference in magnetization direction is a likely indicator of the shock pressure where parallel to apex indicates pressures larger than 10 GPa and perpendicular to apex indicate pressures less than 10 GPa. Intensities of NRM and saturation isothermal remanent magnetization (SIRM) contrast and fluctuate within a shatter cone as well as in between two sites. We observed a random orientation of magnetic vector directions and amplitudes changing over small scales leading to the absence of coherent macro-scale signature.K e y w o r d s :

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“…Indeed, SNCs have been more likely magnetized during or after impact than during the initial magmatic cooling. Therefore, it is more significant to estimate the in situ NRM for the Noachian equivalents of SNCs by using their saturation IRMs and the proposed upper bound of 2% for NRM/IRM in case of TRM in an Earth-like field for magnetite or pyrrhotite (Kletetschka et al 2003). Taking 5 A/ m for the minimal crustal NRM (e.g., Parker 2003) and a mass density of 3 leads to a minimum saturation IRM of 83 10 −3 Am 2 /kg (Fig.…”

Section: Remanence Intensitymentioning

confidence: 99%