scholarly journals New criteria for selecting reliable Thellier-type paleointensity results from the 1960 Kilauea lava flows, Hawaii

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Doohee Jeong ◽  
Qingsong Liu ◽  
Yuhji Yamamoto ◽  
Yongjae Yu ◽  
Xiang Zhao ◽  
...  
Keyword(s):  
Remanent Magnetization ◽  
Magnetic Particles ◽  
Magnetic Field Intensity ◽  
Treatment Temperature ◽  
Lava Flows ◽  
Thermal Alteration ◽  
Earth Magnetic Field ◽  
New Criteria ◽  
Hysteresis Parameter ◽  
Thermal Remanent Magnetization

AbstractThellier-type paleointensity experiments associated with partial thermal remanent magnetization checks have been widely used to determine paleointensity values from volcanic and archaeological media. However, previous studies have revealed that a substantial portion of paleointensity results with positive checks for historical lava samples largely fails to predict known Earth magnetic field intensity values. To determine the fidelity of paleointensity values, conventional Thellier-type paleointensity experiments were performed on Kilauea lava flows that erupted in 1960. The positive partial thermal remanent magnetization checks for our results range from 30.28 ± 1.38 µT to 52.94 ± 1.89 µT. This strongly indicates that conventional paleointensity checks cannot guarantee the fidelity of paleointensity results, especially when the unblocking temperatures for the newly formed magnetic particles are higher than the treatment temperature. Therefore, in this study, to check for thermal alteration during heating, the temperature dependence of the hysteresis parameter measured at room temperature for the thermally treated samples was also measured. Our new results show that nearly all biased paleointensity values correspond to a ratio of the coercivity of remanence to the magnetic coercivity of > 3 and a chemical alteration index > ~ 10%, which indicates the strong effect of the domain state and thermal alteration on the fidelity of the paleointensity results. Our study provides feasible criteria to further improve the fidelity of paleointensity estimations.

scholarly journals New Criteria for Selecting Reliable Thellier-Thellier type Paleointensity Results from the 1960 Kilauea Lava Flow, Hawaii

2020 ◽  
Author(s):  
Doohee JEONG ◽  
Qingsong Liu ◽  
Yuhji YAMAMOTO ◽  
Yongjae YU ◽  
Xiang ZHAO ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Particles ◽  
Substantial Portion ◽  
Temperature Dependent ◽  
Thermal Alteration ◽  
Domain State ◽  
Almost All ◽  
New Criteria ◽  
Hysteresis Parameter ◽  
Thermal Remanent Magnetization

Abstract Thellier-Thellier type paleointensity experiments associated with partial thermal remanent magnetization (pTRM) checks have been widely used to determine paleointensity values from volcanic and archaeological media. However, previous studies further revealed that a substantial portion of paleointensity results with positive checks for historical lavas largely fails to predict the known Earth’s field intensity values. To determine the fidelity of paleointesnity values, conventional Thellier-Thellier type paleointensity experiments have been performed from the Kilauea lava flows erupted in 1960. Our results show that positive pTRM checks range from 30.34±1.39 to 53.04±1.80 μT. This strongly indicates that positive pTRM checks can’t guarantee the fidelity of paleointensity results especially when the unblocking temperatures for the newly-formed magnetic particles are higher than the treated temperature. Thus, in this study, to check thermal alteration during heating, the temperature-dependent of hysteresis parameter measured at the room-temperature for the thermally-treated samples were also measured. Our new results show that almost all biased paleointensity values correspond to Bcr /Bc >3 and CI >~10%, which indicates strong effects of domain state and thermal alteration on the fidelity of paleointensity results. Our study provides a feasible criteria to further improve the fidelity of paleointensity estimations.

Infidélité paléomagnétique observée dans une formation lacustre varvée quaternaire dite: "argiles d'Eybens" (Grenoble, France)

1982 ◽  
Vol 19 (6) ◽  
pp. 1196-1217 ◽  
Author(s):  
Daniel Biquand
Keyword(s):  
Remanent Magnetization ◽  
Axial Direction ◽  
Field Studies ◽  
Particle Orientation ◽  
Easy Magnetization ◽  
Magnetization Direction ◽  
Continuous Field ◽  
Very High ◽  
Different Levels ◽  
Thermal Remanent Magnetization

We have investigated the properties of natural magnetization of a lacustrine interglacial Riss–Würm deposit near Grenoble (France). Made up of accumulated argillite 250 m thick, this deposit comprises annual varves with an average thickness of 0.5 cm.The magnetic viscosity of this sediment is not very high, and we have demonstrated that the characteristic magnetization, measured after a moderate thermal treatment (between 160 and 220 °C) followed by alternating field demagnetization with maximum intensity at 200 Oe (15.9 × 103 A/m), is possibly a detrital magnetization carried by the magnetite (thermomagnetic and strong continuous field studies).On a local scale (area of about 100 m2), the direction of this magnetization remains very homogeneous within each horizon; sampling restricted to about 10 sites 1 m apart indicates for each level a mean direction of magnetization with a high accuracy: α95 = 1–2°, k = 500–2500. The aveage direction calculated by this method for different levels indicates significant stratigraphic variations (attaining an inclination of 20° and a declination of 50°), which are reached rapidly (from 1 to few degrees per year). Such variations cannot be reasonably attributed to changes in the directions of the Earth's magnetic field.A study of the acquired anisotropy of the thermal remanent magnetization indicates a magnetic anisotropy that is related to the lithological structure of the sediment and shows a strong intensity: the maximum divergence between the field direction and the acquired thermal remanent magnetization direction in this field varies, with individual samples, between 9 and 50°. The study of the properties of this anistotropy demonstrates the "infidelity" of the detrital magnetization: for one of the small vertical sequences studied for anisotropy the characteristic magnetization of a specified level has a direction nearer the axial direction of easy magnetization when the anisotropic intensity is large. This infidelity may be caused by different factors influencing the deposition of the sediment, particularly the variable directions of water flows determining the particle orientation. [Journal Translation]

Multi-proxy study of the Cretaceous-Paleogene (K-Pg) boundary in deep-sea turbiditic sediments in the Uzgruň section (Outer Flysch Carpathians, Czech Republic)

2021 ◽  
Author(s):  
Šimon Kdýr ◽  
Tiiu Elbra ◽  
Miroslav Bubík ◽  
Petr Schnabl ◽  
Lilian Švábenická
Keyword(s):  
Magnetic Susceptibility ◽  
Czech Republic ◽  
Detection Limit ◽  
Remanent Magnetization ◽  
Magnetic Particles ◽  
Principal Component ◽  
Natural Remanent Magnetization ◽  
Ongoing Research ◽  
Small Stream ◽  
Magnetic Methods

<p>The composite profile, with 4 studied sections, is located near the Uzgruň village (Czech Republic) next to a small stream. The profile is composed of Late Maastrichtian to Palaeocene flysch sediments and the K-Pg boundary is set in claystones within this turbiditic setting. Ongoing research of local paleoenvironment and stratigraphy is based on paleo- and rock-magnetic methods, micropaleontology and geochemistry to obtain more detailed view of the local situation during the K-Pg extinction event. Based on biostratigraphy, two dinocyst zones (Bubík et al., 2002): Palynodium grallator and Carpatella cornuta (first occurrence in the Danian), two calcareous nannofossil zones in the Upper Maastrichtian, and the agglutinated foraminifer zone Rzehakina fissistomata in the Paleogene were distinguished. Biostratigraphic data support the K-Pg boundary interval. The uppermost Maastrichtian is indicated by nannofossil species Micula prinsii, UC26d<sup>TP</sup> zone. Basal Paleogene non-calcareous strata contain dinocyst Carpatella cornuta and agglutinated foraminifers of Rzehakina fissistomata zone. The presence of low-latitude nannofossil taxa M. prinsii and Ceratolithoides kamptneri show input of warm waters during the uppermost Maastrichtian. Several rock-magnetic methods, such as acquisition of Isothermal remanent magnetization (IRM), acquisition of Anhysteretic remanent magnetization (ARM), Anisotropy of magnetic susceptibility (AMS), Field dependence of magnetic susceptibility (HD) and Frequency dependence of magnetic susceptibility (FD), were applied to estimate behaviour and origin of magnetic particles. Natural remanent magnetization (NRM) values of samples range from 0.09 to 2.48 mA/m. Volume normalized magnetic susceptibility (MS) show values from 130 up to 1197 SI*10-6. There is no increase observed in MS across stratigraphic boundary due to turbiditic evolution of sediment. Due to character of sediments, we applied alternating field (AF) demagnetization and used principal component analysis (PCA; Kirschvink, 1980) for estimation of characteristic remanent component. Most of the K/Pg sections worldwide have well documented Iridium anomaly. In Uzgruň, the preliminary results show that although the values are not as pronounced, the Ir at K-Pg boundary is still higher than in surrounding sediments. For tracing of Deccan traps effect we plan to apply mercury (Hg)/total organic carbon (TOC) stratigraphy. TOC content of 20 pilot samples is low, but not under detection limit of the instrumentation (mean value 0.92 wt%). One sample reached value 4.41 wt% of TOC. Sulphur contents are reaching 1 wt%, but several samples were under detection limit of the instrumentation. Sulphur concentrations suggest more reduction conditions of burial.</p><p>Current research is supported by Czech Science Foundation project no. 19-07516S and is in accordance with research plan no. RVO67985831.</p><p>Bubík, M., Adamová, M., Bąk, M., Franců, J., Gedl, P., Mikuláš, R., Švábenická, L., & Uchman, A. (2002). Výsledky výzkumu hranice křída/terciér v magurském flyši u Uzgruně. Geologické výzkumy na Moravě a ve Slezsku, 9, 18–22</p><p>L. Kirschvink (1980), The least-squares line and plane and the analysis of palaeomagnetic data, Geophysical Journal International, 62(3), 699–718, https://doi.org/10.1111/j.1365-246X.1980.tb02601.x</p>

Photo-induced magnetic behavior in the amorphous spin-glass material Co3(SbTe3)2

1994 ◽  
Vol 9 (4) ◽  
pp. 909-914 ◽  
Author(s):  
Biao Wu ◽  
Lianwei Ren ◽  
Charles J. O'Connor ◽  
Jinke Tang ◽  
Jin-Seung Jung ◽  
...  
Keyword(s):  
Spin Glass ◽  
Remanent Magnetization ◽  
Magnetic Behavior ◽  
Freezing Temperature ◽  
Specific Resistivity ◽  
Metathesis Reaction ◽  
Isothermal Remanent Magnetization ◽  
Magnetization Data ◽  
Magnetizing Field ◽  
Thermal Remanent Magnetization

A new ternary material Co3(SbTe3)2 was prepared by using a rapid precipitation metathesis reaction between the Zintl material K3SbTe3 and CoCl2 in aqueous solution. The dc specific resistivity of this material is in the region for metallic conductors (p = 2.75 × 10-3 Ω-cm). The dc magnetic susceptibility of Co3(SbTe3)2 is reported over a 2.2 K-300 K temperature region, and the material is characterized as a spin glass with a freezing temperature of about 5 K. Magnetization data are also reported as both thermal remanent magnetization and isothermal remanent magnetization as a function of magnetizing field and temperature. When cooled well below the glass freezing temperature, the frozen spin glass has been observed to exhibit photomagnetic effects consistent with a disruption of the spin-glass state caused by uv-radiation.

The Iceland Research Drilling Project crustal section: stable remagnetization below 3 km crustal depth

1988 ◽  
Vol 25 (8) ◽  
pp. 1304-1315 ◽  
Author(s):  
James M. Hall ◽  
Brian E. Fisher
Keyword(s):  
Grain Size ◽  
Hydrothermal Alteration ◽  
Remanent Magnetization ◽  
Drill Hole ◽  
Lava Flows ◽  
Crustal Layer ◽  
Transition Zones ◽  
Mixed Polarity ◽  
History Of ◽  
Drilling Project

A section at below 3.1 km depth in Icelandic crust, sampled in the 1978 Icelandic Research Drilling Project drill hole, contains a number of subaerially deposited lava flows showing both downwards and probably original upwards inclinations of cleaned, stable remanent magnetization. Such "mixed polarities" are inconsistent with an initial cooling thermoremanent origin for the magnetization. An attempt is made to identify the factors involved in producing these mixed polarities and to consider the possible wider importance of the results. The mixed-polarity flows have experienced intense hydrothermal alteration, followed by the widespread deposition of secondary magnetite. Secondary magnetite, which is formed in relatively anhydrous conditions associated with dike intrusion, dominates primary magnetite volumetrically where dike density locally exceeds about 30%.Where secondary magnetite is very dominant or is the only type of magnetite present, directional remagnetization appears to be uniform and complete. Where secondary and primary magnetite are both important, relatively high remanence and saturation magnetizations, total magnetite and primary magnetite grain size, and low deuteric oxidation state of primary magnetite are all associated with downwards directional remagnetization. It appears that a complex balance of the properties and history of primary and secondary magnetite, in addition to the relative abundances of these phases, controls the final stable polarity of samples.If the narrow transition zones between little-altered extrusives, greenschist-facies flows and dikes of the Troodos (Cyprus) ophiolite, and DSDP hole 504B are typical of oceanic crust, a narrow ~0.2 km interval of mixed polarities may be underlain in some locations by an intermediate crustal layer in polarity opposition with the uppermost, little-altered, extrusive layer.

scholarly journals Ultrafine Magnetic Particles: A DIET-Proxy in Organic Rich Sediments?

2021 ◽  
Vol 8 ◽  
Author(s):  
Andrea Teixeira Ustra ◽  
Carlos Mendonça ◽  
Aruã da Silva Leite ◽  
Melina Macouin ◽  
Rory Doherty ◽  
...  
Keyword(s):  
Ultrafine Particles ◽  
Remanent Magnetization ◽  
Magnetic Particles ◽  
Environmental Magnetism ◽  
Magnetic Fraction ◽  
Biogeochemical Processes ◽  
Isothermal Remanent Magnetization ◽  
Simple Measurement ◽  
Brownfield Site

In this work we present results of the magnetic properties characterization of sediment samples from a brownfield site that is generating methane biogas in São Paulo–Brazil. We applied interpretation procedures (frequency dependent susceptibility and time-dependent Isothermal Remanent Magnetization) appropriate to study the ultrafine magnetic fraction response of the samples. The higher content of superparamagnetic (SP) particles correlates well with the detected biogas pockets, suggesting that the methanogens activity produces these ultrafine particles, different from the magnetic particles at other depth levels. We propose the use of two simple measurement and interpretation techniques to identify such magnetic particles fingerprints. The results presented here support the use of environmental magnetism techniques to investigate biogeochemical processes of anaerobic microbial activity.

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