Self-reversal of remanent magnetization in basalts due to partially oxidized titanomagnetites

Krása, David; Щербаков, В. П.; Kunzmann, Thomas; Petersen, N.

doi:10.1111/j.1365-246x.2005.02656.x

Cited by 68 publications

(58 citation statements)

References 58 publications

(105 reference statements)

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“…[25] It has long been known that self-reversal of thermoremanence could be caused by negative magnetic coupling between two phases [e.g., Havard and Lewis, 1965;Tucker and O'Reilly, 1980;Heller and Petersen, 1982;Krása et al, 2005]. Our rock magnetic analyses indicate there are at least two magnetic phases existing in samples heated to temperatures between 300 and 500°C, e.g., the higher T c Ti-poor phase (magnetite) and the lower T c Ti-rich ATM phase.…”

Section: Discussionmentioning

confidence: 85%

“…The phase interaction (e.g., negative magnetic couplings) may cause the observed pTRM acquisition decrease with elevated treatment temperatures. Krása et al [2005] observed the influence of oxidation on the domain configuration using a magnetic force microscopy and found that the two magnetically coupled phases lead to the lower T c phase acquiring a TRM in a direction antiparallel to the applied external magnetic field. Their numerical modeling indicated that the domain configuration is capable of causing partial and complete self-reversal due to phase coupling of the two phases.…”

Section: Discussionmentioning

confidence: 99%

“…This makes it feasible to determine under which conditions selfreversal of RM could occur and then to decipher the corresponding mechanisms that control the self-reversal processes. Recently, Krása et al [2005] carried out comprehensive rock magnetic experiments and numerical modeling studies on continental basalts from Olby (France) and Vogelsberg (Germany). Their results revealed that partial and/or full self-reversal of RM in basalt are caused by phase coupling of two side-by-side phase assemblages with different blocking temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…Later, O'Reilly and Banerjee [1966] found that very high oxidation state and high temperature are prerequisites for self-reversal of RM. Self-reversal of TRM could also be caused by negative magnetic coupling [e.g., Havard and Lewis, 1965;Tucker and O'Reilly, 1980;Heller and Petersen, 1982;Krása et al, 2005].…”

Section: Introductionmentioning

confidence: 99%

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Thermally induced inversion of Al‐substituted titanomagnetite in basalts: Evidence for partial self‐reversal

et al. 2006

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[1] We report properties of laboratory-induced thermoremanence combined with detailed rock magnetic experiments on basaltic samples which contain aluminum-substituted titanomagnetite (Fe 2.24 Ti 0.64 Al 0.12 O 4 ). Prior to Thellier-Coe paleointensity experiments, specimens were first demagnetized using an alternating field with a peak field of 90 mT and were then imparted an anhysteretic remanent magnetization (ARM) to represent a natural remanent magnetization (NRM). Results show that the partial thermal remanent magnetization (pTRM) gain and ARM remaining are linearly correlated up to 300°C. Between 300 and 460°C, specimens acquire thermoremanence with a direction antiparallel to the external field direction, leading to intensity decreases. This coincides with the onset of the mineral transformation from Al-titanomagnetite to a magnetic phase with higher T c . Our results support that phase interaction with distinct T c values in partially oxidized titanomagnetite can produce partial self-reversal thermoremanence in rocks.Citation: Pan, Y., Q. Liu, C. Deng, H. Qin, and R. Zhu (2006), Thermally induced inversion of Al-substituted titanomagnetite in basalts: Evidence for partial self-reversal,

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Section: Discussionmentioning

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermally induced inversion of Al‐substituted titanomagnetite in basalts: Evidence for partial self‐reversal

et al. 2006

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“…A goal of the work was to find and identify the low-temperature oxidized Ti-Mgh -disordered-antiferromagnetic phase. The self-reversed origin of reversed RM of submarine basalts was revealed also by Doubrovine and Tarduno (2004), in basalts also by Krása et al (2005), also by Pan et al (2006). I have been studying the literature concerning the problem of the reversed RM bearing volcanics and the sedimentary rocks.…”

Section: Discussionmentioning

confidence: 99%

The self-reversal origin of the reversed remanent magnetization in the igneous rocks containing the oxidized Fe-Ti oxide solid solutions

Orlický

2011

Contributions to Geophysics and Geodesy

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I study the magnetic and paleomagnetic characteristics of the Pleistocene to Quaternary basalts from the West Carpathian Mountains. I have revealed the existence of the so-called self-reversal remanent magnetization bearing disordered-antiferromagnetic Fe-Ti phases, with the Néel temperatures of either TN = 430−450• C (the Ti-Mgh phases) or with TN = 460 − 470• C (Hem-Ilm phases). I have suggested for the first time to name of these phases in this article. It is very important that these phases are the only sources of the reversed RM, of the self-reversal origin, probably of the chemical remanent magnetization (CRM) origin. The basalts of Southern Slovakia were differentiated to these of the magnetite and Ti-rich Ti-Mt bearing rocks with normal polarity of RM, and those with the presence of the self-reversal RM bearing disordered-antiferromagnetic Ti-Mgh phases of the TN = 430 to 450• C, and those of the disordered-antiferromagnetic Hem-Ilm phases of the TN = 460 − 470• C, both of only reversed RM of the self-reversal origin. I present the original model based on the principe that the magnetite, hematite and Ti-rich titanomagnetite bearing rocks, without any disordered-antiferromagnetic phases, carry only normal -positive RM. The self-reversal remanent magnetization bearing disorderedantiferromagnetic magnetic phases of Fe-Ti oxide solid solutions carry only reversed remanent magnetization in the rocks. This model has been involved to explain the reversed or normal RM of submarine igneous rocks published in the literature. We anticipate that in all continental or submarine reversally magnetized rocks the disordered-antiferromagnetic Fe-Ti phases would be revealed, either in their initial, complete developed stages, or as the remnants of these phases.We suggest that the reverse remanent magnetization of rocks is due to the existence of the self-reversal remanent magnetization bearing disordered-antiferromagnetic magnetic phases of Fe-Ti solid solutions in the rocks, but not due to the existence of the reversals of the geomagnetic field.

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Magnetic characterization of synthetic titanomagnetites: Quantifying the recording fidelity of ideal synthetic analogs

Almeida

Muxworthy

Williams

et al. 2014

Geochem Geophys Geosyst

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A series of four synthetic basalts comprising titanomagnetite (Fe3‐xTixO4) grains of varied size and titanium content have been produced by a glass‐ceramic method. Complementary characterization techniques of X‐ray diffractometry, secondary electron microscopy, and transmission electron microscopy (TEM) demonstrate the reaction product composition consisted of mainly Fe3‐xTixO4, pyroxene hedenbergite, fayalite, and SiO2. The samples exhibit bimodal distributions of larger (<2 µm) and smaller Fe3‐xTixO4 particles (<50 nm in diameter), the latter found inside pyroxene crystals, as well as the sporadic occurance of dendritic Fe3‐xTixO4 structures. Magnetic measurements show their bulk characteristics fall into two groups: Ti‐rich titanomagnetite samples with varying Ti content; and near‐stoichiometric magnetite. The TEM technique of off‐axis electron holography allowed for visualization of the magnetic behavior of the synthetic Fe3‐xTixO4 grains. Energy dispersive X‐ray analysis and off‐axis electron holography confirmed the small Fe3‐xTixO4 grains (<50 nm) confined within glassy pyroxene regions to be Fe‐rich and single domain, carrying strong magnetic signals, compared to the relatively magnetically weak larger Fe3‐xTixO4 grains (x ∼ 0.6). The large grains in the pure magnetite sample are shown to be pseudo‐single domain in nature. The quenching process involved in synthesis is considered similar to that of pillow basalts found at mid‐ocean ridges and hence the reaction products are thought ideal in terms of characterization and understanding, for the purpose of studying natural systems.

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Self-reversal of remanent magnetization in basalts due to partially oxidized titanomagnetites

Cited by 68 publications

References 58 publications

Thermally induced inversion of Al‐substituted titanomagnetite in basalts: Evidence for partial self‐reversal

Thermally induced inversion of Al‐substituted titanomagnetite in basalts: Evidence for partial self‐reversal

The self-reversal origin of the reversed remanent magnetization in the igneous rocks containing the oxidized Fe-Ti oxide solid solutions

Magnetic characterization of synthetic titanomagnetites: Quantifying the recording fidelity of ideal synthetic analogs

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