scholarly journals Chemical Remanent Magnetization of Ferromagnetic Minerals and Its Application to Rock Magnetism

1959 ◽  
Vol 10 (3) ◽  
pp. 99-117 ◽  
Author(s):  
Kazuo KOBAYASHI
Keyword(s):  
Remanent Magnetization ◽  
Rock Magnetism ◽  
Chemical Remanent Magnetization

Acquisition of chemical remanent magnetization by synthetic iron oxide

Nature ◽  
1987 ◽  
Vol 327 (6123) ◽  
pp. 610-612 ◽  
Author(s):  
Laura B. Stokking ◽  
Lisa Tauxe
Keyword(s):  
Iron Oxide ◽  
Remanent Magnetization ◽  
Chemical Remanent Magnetization

Paleomagnetism and U–Pb geochronology of the Clarence Head dykes, Arctic Canada: orthogonal emplacement of mafic dykes in a large igneous province

2009 ◽  
Vol 46 (3) ◽  
pp. 155-167 ◽  
Author(s):  
Steven W. Denyszyn ◽  
Don W. Davis ◽  
Henry C. Halls
Keyword(s):  
Remanent Magnetization ◽  
High Arctic ◽  
Large Igneous Province ◽  
Dyke Swarm ◽  
Canadian High Arctic ◽  
The North ◽  
Igneous Province ◽  
The Difference ◽  
Age Range ◽  
Chemical Remanent Magnetization

The north–south-trending Clarence Head dyke swarm, located on Devon and Ellesmere Islands in the Canadian High Arctic, has a trend orthogonal to that of the Neoproterozoic Franklin swarm that surrounds it. The Clarence Head dykes are dated by the U–Pb method on baddeleyite to between 716 ± 1 and 713 ± 1 Ma, ages apparently younger than, but within the published age range of, the Franklin dykes. Alpha recoil in baddeleyite is considered as a possible explanation for the difference in ages, but a comparison of the U–Pb ages of grains of equal size from both swarms suggests that recoil distances in baddeleyite are lower than those in zircon and that the Clarence Head dykes are indeed a distinctly younger event within the period of Franklin magmatism. The Clarence Head dykes represent a large swarm tangential to, and cogenetic with, a giant radiating dyke swarm ∼800 km from the indicated source. The preferred mechanism for the emplacement of the Clarence Head dykes is the exploitation of concentric zones of extension around a depleting and collapsing plume source. While the paleomagnetism of most Clarence Head dykes agrees with that of the Franklin dykes, two dykes have anomalous remanence directions, interpreted to be a chemical remanent magnetization carried by pyrrhotite. The pyrrhotite was likely deposited from fluids mobilized southward from the Devonian Ellesmerian Orogeny to the north that used the interiors of the dykes as conduits and precipitated pyrrhotite en route.

Linking cave sediments and soil magnetism in the Urșilor cave (Romania)

2021 ◽  
Author(s):  
Cristian George Panaiotu ◽  
Cristian Necula ◽  
Relu D. Roban ◽  
Alexandru Petculescu ◽  
Ionut-Cornel Mirea ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Frequency Dependence ◽  
Remanent Magnetization ◽  
Rock Magnetism ◽  
Magnetic Mineral ◽  
Magnetic Data ◽  
Sediment Samples ◽  
Superparamagnetic Particles ◽  
Susceptibility Data ◽  
Cave Sediments

<p>Cyclical changes in the magnetic mineral assemblages have been observed in numerous sedimentary records confirming the relationship between rock magnetism and past global change. Several studies have shown that the magnetic susceptibility data of cave sediments reflect both long- and short-term climatic oscillations. These magnetic susceptibility variations are attributed to changes in climate-controlled pedogenesis which influence the production of low coercivity magnetic mineral phases, magnetite, and maghemite outside the cave. These soils with climate-dependent magnetic properties are then washed, blown, or tracked into the cave where they accumulate, creating the changes observed in rock magnetic data. We present a rockmagnetism study of the sediments from the Urșilor cave and the soils above the cave. Our focus is the detailed characterization of the ferromagnetic mineralogy preserved in the cave sediments and its links with potential soil sources. In the cave, we sampled four sections (2-3 m high) consisting mainly of silts and clays, with some sand layers. The age of the sediments is older than 40 ka. At the surface, we sampled various types of soils from 9 sites. For all samples, we measured: variation of magnetic susceptibility with frequency (976 and 15616 Hz), the anisotropy of magnetic susceptibility, isothermal remanent magnetization, and anhysteretic remanent magnetization. Because soils are characterized by the presence of superparamagnetic magnetite produced by pedogenesis which can be detected by the frequency dependence of magnetic susceptibility, we also measured the frequency dependence of soils and selected cave sediment samples at 13 frequencies (between 128 and 512000 Hz). Multi-frequencies measurements of the magnetic susceptibility of recent soils show that all the sampled soils have a strong frequency dependence indicating the presence of superparamagnetic particles produced by pedogenesis. Most of the sediment samples have an important frequency dependence similar to the one observed in the recent soils. As a preliminary conclusion, we can state that most of the fine cave sediments contain superparamagnetic particles, which can be probably attributed to soils transported into the cave by erosion. These results suggest that during the deposition of high magnetic susceptibility sediments it was a climate favorable for intense pedogenesis. The interpretation of the intervals with lower values of magnetic susceptibility is still under investigation to decide if represents a climatic signal or a change in the dynamics of sediment transport. <strong>Acknowledgment:</strong> The research leading to these results has received funding from the EEA Grants 2014-2021, under Project contract no. EEA-RO-NO-2018-0126.</p>

Identifying and Dating the Destruction of Hydrocarbon Reservoirs Using Secondary Chemical Remanent Magnetization

2019 ◽  
Vol 46 (20) ◽  
pp. 11100-11108
Author(s):  
Yong Zhang ◽  
Adrian R. Muxworthy ◽  
Dong Jia ◽  
Guoqi Wei ◽  
Bin Xia ◽  
...  
Keyword(s):  
Remanent Magnetization ◽  
Hydrocarbon Reservoirs ◽  
Secondary Chemical ◽  
Chemical Remanent Magnetization

Redox chemical remanent magnetization—A new dimension in exploration for sulfide deposits in volcanic covered areas

Geophysics ◽  
1981 ◽  
Vol 46 (8) ◽  
pp. 1169-1181 ◽  
Author(s):  
Lloyal O. Bacon ◽  
Charles L. Elliot
Keyword(s):  
Remanent Magnetization ◽  
Field Tests ◽  
Massive Sulfide ◽  
Rock Properties ◽  
Sulfide Deposit ◽  
Magnetic Memory ◽  
Sulfide Deposits ◽  
Surface Redox ◽  
Chemical Remanent Magnetization

Redox chemical remanent magnetization (CRM) results from current flow associated with a redox potential cell. An active redox cell covered by later volcanics may continue in operation for a period of time, sufficiently long that the current flowing in the overlying volcanics will cause or assist in the remobilization of iron. The remobilization may be either in situ as an alteration of minerals or by actual migration as a ferrous hydroxide, with fixation at a higher Eh nearer the surface. Redox CRM will leave a characteristic pattern as a magnetic memory in the rocks. Measurement of the magnetic rock properties and interpretation of resulting patterns can be used to locate the ancient redox cell. Redox cells in nature are usually associated with oxidizing sulfide deposits. Under appropriate conditions, redox CRM can be utilized as an indirect method for sulfide exploration. Field results for two porphyry sulfide deposits and a massive sulfide deposit under approximately 400 m of post‐mineral volcanic cover demonstrate the feasibility of this technique. Field tests in nonsulfide areas indicate that pervasive occurrence of false redox CRM anomalies do not exist except in the presence of sulfides. Laboratory experiments in the simulation of the redox CRM concept give support to the theory.

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