Pressure effects on martian crustal magnetization near large impact basins

Kletetschka, Günther; Connerney, J. E. P.; Ness, N. F.; Acuña, M. H.

doi:10.1111/j.1945-5100.2004.tb00079.x

Cited by 48 publications

(60 citation statements)

References 37 publications

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“…Note that there is an unaccounted absence of magnetic anomalies (which could be due to smaller block sizes containing coherent magnetization) around its basin. However the presence of strong anomalies in proximity of this basin reveals a resistance against impact demagnetization supporting large crustal magnetic coercivity (Kletetschka et al 2004b). The pressure gradient that must have occurred during the impact event was estimated while considering the impact basin diameter and the evidence of presence of large magnetic anomalies indicates anomalous resistance against impact demagnetization-large crustal magnetic coercivity.…”

Section: Introductionmentioning

confidence: 92%

“…2; Fig. 1 in Kletetschka et al [2004b]). Note that there is an unaccounted absence of magnetic anomalies (which could be due to smaller block sizes containing coherent magnetization) around its basin.…”

Section: Introductionmentioning

confidence: 93%

“…This has been verified experimentally and numerically. Magnetic anomalies vanish near the impact basins and the crustal magnetic coercivity controls the rate of magnetic decay near the basins (Kletetschka et al 2004b). Figure 1 shows that these craters are within zone 1 and adjacent to zone 2.…”

Section: Introductionmentioning

confidence: 98%

“…2) and therefore the magnetic anomaly decay near this basin is critical for characterization of the magnetic carriers in this region. In fact, the steep magnetic decay towards the center of the Prometheus basin suggests that the crustal magnetic minerals most likely have large magnetic coercivity (Kletetschka et al 2004b). …”

Section: Introductionmentioning

confidence: 99%

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Magnetic zones of Mars: Deformation‐controlled origin of magnetic anomalies

Kletetschka

Lillis

Ness

et al. 2009

Meteorit & Planetary Scien

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Abstract-Intense magnetic anomalies over Martian surface suggest preservation of large volumes of very old crust (>3 Gyr) that formed in the presence of a global magnetic field. The global distribution of the magnetic intensities observed above the Martian crust suggests a division into three zones. Zone 1 is where the magnetic signature is negligible or of relatively low intensity at Mars Global Surveyor (MGS) satellite mapping altitude (400 km). Zone 2 is the region of intermediate crustal magnetic amplitudes and zone 3 is where the highest magnetic intensities are measured. Crater demagnetization near zone 3 reveals the presence of rocks with both high magnetic intensity and coercivity. Magnetic analyses of terrestrial rocks show that compositional banding in orogenic zones significantly enhances both magnetic coercivity and thermal remanent magnetization (TRM) efficiency. Such enhancement offers a novel explanation for the anomalously large intensities inferred of magnetic sources on Mars. We propose that both large magnetic coercivity and intensity near the South Pole is indicative of the presence of a large degree of deformation. Associated compositional zoning creates conditions for large scale magnetic anisotropy allowing magnetic minerals to acquire magnetization more efficiently, thereby causing the distinct magnetic signatures in zone 3, expressed by intense magnetic anomalies. We use a simple model to verify the magnetic enhancement. We hypothesize that magnetically enhanced zone would reside over the down welling plume at the time of magnetization acquisition.

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Magnetic zones of Mars: Deformation‐controlled origin of magnetic anomalies

Kletetschka

Lillis

Ness

et al. 2009

Meteorit & Planetary Scien

Self Cite

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“…Srnka et al (1979) showed the acquisition of SRM by an impact of aluminum and basalt at velocity of 13-15 km/s. Kletetschka et al (2004) showed that pressures of about 1 GPa are sufficient to partially demagnetize all of magnetite, hematite, and titanohematite. Wasilewski (1976Wasilewski ( , 1977 and Dickinson and Wasilewski (2000) reported remanent magnetization acquired by shock to 5 GPa in magnetic and nonmagnetic environments using samples containing precipitated grains of anti-ferromagnetic iron (nonmagnetic fcc-phase) in a copper field.…”

Section: Introductionmentioning

confidence: 99%

Acquisition of shock remanent magnetization for demagnetized samples in a weak magnetic field (7 μT) by shock pressures 5–20 GPa without plasma‐induced magnetization

Funaki

Syono

2008

Meteorit & Planetary Scien

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Abstract-Demagnetized samples of cobalt precipitates in a copper matrix were shocked to 5, 10, and 20 GPa in a weak magnetic field of 7.7 µT to elucidate the origins of the natural remanent magnetization of meteorites and the magnetic anomalies of impact craters on the moon and Mars. The samples placed in the target acquired shock remanent magnetization (SRM) whose intensity increased up to 21.3 times compared with the demagnetized state, but SRM intensity and shock intensity were not correlated. The SRM direction was in most cases approximately perpendicular to the shock direction. The samples placed 4.8 mm from the impacted surface did not acquire significant magnetization, suggesting no plasma-induced remanent magnetization (PIRM) up to 20 GPa. When the samples were divided into 8 sub-samples, the SRM intensities of sub-samples increased up to 40 times compared with bulk ones and their directions were scattered. Higher coercive force grains were magnetized perpendicular to the shock direction for shocks of 5 and 10 GPa, but at 20 GPa the directions were less systematically oriented. These results suggest that the proposed plasma-induced magnetization of impactites should be reconsidered.

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Effect of static pressure on absolute paleointensity recording with implications for meteorites

Volk

Gilder

2016

JGR Solid Earth

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We investigated the influence of hydrostatic and nonhydrostatic stress on the recording process of magnetic field intensity with particular relevance for meteorites that experienced pressures lower than 5 GPa corresponding to the lowest shock stage classification (S1) in meteorites. Thermal remanent magnetizations were imparted on natural obsidian samples containing pseudo‐single domain titanomagnetite, analogous to some achondritic meteorites. Thellier‐type paleointensity experiments were carried out at ambient conditions after pressure cycling to 0.6, 1.2, and 1.8 GPa. Each experiment used 10 samples to assess reproducibility, which is better than ±5%. The recorded paleointensity decreased 10%/GPa under hydrostatic stress and 20%/GPa under nonhydrostatic stress, leading to the fundamental conclusion that paleointensity results from meteorites may be appreciably underestimated. Pressure cycling shifts the blocking and unblocking spectra, thereby producing more linear slopes on an Arai diagram with increasing strain. We explain why, for samples with a single magnetization component that does not alter, a two‐step paleointensity protocol sufficiently resolves the true paleointensity. Moreover, we propose that pressure cycling of pseudo‐single domain bearing samples will remove the inherent curvature of the Arai slope, thereby allowing one to obtain a more accurate estimate of the true paleointensity. This likely also holds true for samples possessing multidomain grains. Conversely, linear trends on Arai plots in meteorites might have their origin in a pressure effect that does not necessarily reflect the ubiquitous presence of single domain particles.

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Pressure effects on martian crustal magnetization near large impact basins

Cited by 48 publications

References 37 publications

Magnetic zones of Mars: Deformation‐controlled origin of magnetic anomalies

Magnetic zones of Mars: Deformation‐controlled origin of magnetic anomalies

Acquisition of shock remanent magnetization for demagnetized samples in a weak magnetic field (7 μT) by shock pressures 5–20 GPa without plasma‐induced magnetization

Effect of static pressure on absolute paleointensity recording with implications for meteorites

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