Opening: 00AM - 24PM
Application of an Anisotropy-Based Correction to .

The relative continuity and ubiquity of the global sedimentary record makes sediments and sedimentary rocks an ideal target for studies of relative paleointensity (RPI) and the evolution of the Earth's magnetic field. However, processes including flocculation, contact with the substrate, bioturbation, and compaction disrupt this alignment, leading to shallowed remanent inclinations and biased ...

Get Price
Rock magnetic and paleointensity results from .Traduire cette page

Updated mean paleomagnetic poles were calculated for the Upper Cretaceous Tovuz-Paravakar sections (65.6 degrees N, 162.2 degrees E, A(95) = 4.3, paleolatitude = 27.0 +/- 3.4 degrees) and the Upper Jurassic-Lower Cretaceous Kafan section (61.7 degrees N, 158.9 degrees E, A(95) = 4.8 degrees, paleolatitude = 24.7 +/- 3.8 degrees).

Get Price
Paleointensity of the Earth's magnetic field using SQUID ... · Fichier PDF

SQUID microscopy has been used in previous paleomagnetic and rock magnetic studies (see Weiss et al., 2007 and references therein).Forthisstudy,weusedtheNRM/sIRMmethodas the first step for adapting SQUID microscopy to paleointensityexperiments.Thebasictechniquedescribed here should in the future be adaptable to more robust methods like that of Thellier.

Get Price
Reassessment of the eruptive chronology of El .

01.02.2020 · Rock magnetism experiments in air were carried out to identify the remanence carriers and to evaluate the thermal stability of magnetic mineralogy and the suitability of the material to obtain paleointensity (PI) determinations by using a variable field translation balance (AVFTB) from Magnetic Measurements Ltd. These experiments included: (i) progressive isothermal remanence magnetization ...

Get Price
Short reversals of the earth's magnetic field and its ... · Fichier PDF

Therefore, calculation of different ratios of rock magnetic parameters such as ARM/IRM or ARM/κ LF are used to estimate relative grain size variations. If these are large, paleointensity estimates have to be restricted to intervals with minimum variations, or paleointensity estimates have to be corrected for grain size variations, a procedure not well developed up to now. Examples Fig. 3 ...

Get Price
Bulk magnetic domain stability controls paleointensity ... · Fichier PDF

comprehensive rock magnetic and paleointensity data compila-tions, we quantify a stability trend in hysteresis data that charac-terizes the bulk domain stability (BDS) of the magnetic carriers in a paleomagnetic specimen. This trend is evident in both geological and archeological materials that are typically used to obtain pale- ointensity data and is therefore pervasive throughout most paleo ...

Get Price
Rock‐magnetic artifacts on long‐term relative ...

[24] Paleomagnetic and rock‐magnetic analyses of Eocene‐Oligocene sediment cores from IODP Sites U1331, U1332, and U1333 in the eastern equatorial Pacific Ocean and comparison with results from DSDP Site 522 in the South Atlantic Ocean, from which positive correlation between paleointensity and polarity interval length was proposed by Tauxe and Hartl, have led to the following conclusions.

Get Price
Rock magnetic and paleointensity data from .Traduire cette page

01/12/2005 · Here we examine the rock magnetic and paleointensity characteristics of the Jurassic Stormberg (Karoo) lavas of Lesotho. In the 1960's, van Zijl et al. (1962) reported evidence for a magnetic reversal transition from these lavas. Subsequent studies have confirmed the transition.

Author : R. D. Cottrell, J. A. Tarduno, M. K. WatkeysGet Price
A new highresolution geomagnetic relative paleointensity ... · Fichier PDF

coherence with magnetic grain size proxies and yields a record of relative paleointensity peaks and troughs whose amplitudes are very similar to those in the archeomagnetic (ARCMAG) and Lake St. Croix data sets. Features with a wavelength of 1000 years are correlative between the

Get Price
Rock-magnetic artifacts on long-term relative ... · Fichier PDF

Rock-magnetic artifacts on long-term relative paleointensity variations in sediments Toshitsugu Yamazaki Geological Survey of Japan, AIST, 1-1-1 Higashi, Tsukuba, 305-8567, Japan Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8564, Japan ([email protected]) Yuhji Yamamoto Center for Advanced Marine Core Research, Kochi .

Cited by : 24Get Price
Palaeo- and rock magnetic investigations on Late ...Traduire cette page

Palaeo- and rock magnetic investigations carried out on all samples from sediment cores M35003-4 and M78/1_235-1, Tobago Basin. Open in new tab Magnetic extracts and scanning electron microscopy Magnetic extracts were taken from two samples from core M35003-4 (43 and 264 cm depth) and three samples from core M78/1_235-1 (39, 95 and 141 cm depth).

Cited by : 2Get Price
(PDF) Rock magnetic property and .

Rock magnetic property and paleointensity determination on historical Santorini lava flows

Get Price
Studies on rock magnetic and paleointensity of .Traduire cette page

The magnetic mineralogy of all the samples was dominated by ferrimagnetic mineral (magnetite/magnetite with low titanium content), which was suitable for paleointensity measurements. The geomagnetic paleointensity value obtained by subjecting them to modified Thellier and Thellier method, is found to be (48.81±0.15) μT.

Get Price
Paleomagnetism indicates that primary magnetite .

New paleointensity and Pb-Pb radiometric age data from additional zircons meeting robust selection criteria provide further evidence for the fidelity of the magnetic record and suggest a period of high geomagnetic field strength at 4.1 to 4.0 billion years ago (Ga) that may represent efficient convection related to chemical precipitation in Earth's Hadean liquid iron core.

Get Price
Rock magnetic response to climatic changes in .Traduire cette page

Rock magnetic results reveal magnetic uniformities in mineralogy, concentration and grain size along the two cores, thus relative paleointensity variations are acquired. The three normalizers-anhysteresis remanent magnetization (ARM), magnetic susceptibility (?

Get Price
Rock magnetic properties and relative .

01.02.2009 · However, several tests for sedimentary paleointensity based on rock magnetic criteria (Banerjee et al., 1981, Tauxe, 1993) must be performed to establish reliability of the data. King et al. (1983) proposed the concept of "magnetic uniformity", i.e. the absence of changes in relative grain sizes and concentrations. In order to minimize the effects of down-core variability, the natural ...

Get Price
Rock magnetic properties of dusty olivine: .

The mechanism of chondrule formation is an important outstanding question in cosmochemistry. Magnetic signals recorded by Fe-Ni nanoparticles in chondrules could carry clues to their origin. Recently, research in this area has focused on 'dusty olivine' in ordinary chondrites as potential carriers of pre-accretionary remanence. Dusty olivine is characterised by the presence of sub-micron Fe-Ni ...

Get Price
On the features of the geodynamo following reversals or ... · Fichier PDF

magnetic curves. Altogether 54 samples from 21 flows yielded reliable paleointensity estimates. The mean paleointensity of the intermediate ... rocks which satisfy some specific rock-magnetic cri-teria can be used for absolute intensity determination (Kosterov and Prévot, 1999). Judging from scant available data, there is now a general agreement that the intermediate polarity geomagnetic ...

Get Price
Rock-magnetic properties of single zircon crystals .Traduire cette page

This paper reports on the rock-magnetic properties of single zircon crystals, which are essential for future work establishing the reliable paleointensity method using single zircon crystals. Zircon crystals used in this study were sampled from the Nakagawa River, which crosses the Tanzawa tonalitic pluton in central Japan. Rock-magnetic measurements were conducted on 1037 grains of zircons ...

Get Price
A new rock‐magnetic approach to selecting .Traduire cette page

A rock‐magnetic evaluation of LeBoeuf Lake sediments with these techniques indicates that these sediments are suitable for a relative plaeointensity study. The second approach to evaluating the DRM/ARM ratio as a measure of relative paleointensity is direct comparison with absolute paleointensity data. A comparison between the LeBoeuf Lake ...

Cited by : 398Get Price