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1

Use of "4"0Ar/"3"9Ar age spectra and paleomagnetism to unravel the stratigraphy of a large silicic volcanic field, southwestern Mexico  

International Nuclear Information System (INIS)

Short Communication.

2

Paleomagnetic view on lithosphere kinematics. The example of southern Tibet and the higher Himalayan crystalline  

International Nuclear Information System (INIS)

Complete text of publication follows. Paleomagnetic study in southern Tibet and the Higher Himalayan Crystalline (HHC) was twofold: (1) the recognition of vertical and horizontal block rotations and (2) the examination of the high grade metamorphic rocks (gneisses) from the HHC for their suitability for paleomagnetic investigations. Toward the separation of local and regional tectonic effects, the results from southern Tibet reflect a regional trend in agreement with oroclinal bending and rotational under-thrusting. On the other hand, measured 'anomalous inclinations' are interpreted as a consequence of extensional tectonic, and the circular distribution of magnetic remanences is attributed to long wavelength folding within the study area as well as doming in the crust. The examination of the high grade metamorphic rocks was successful: The high quota of isolated stable and well grouping secondary magnetic remanences, demonstrate their ...

2009-08-23

3

Preliminary investigation of the magnetostratigraphy of the Ringold Formation  

International Nuclear Information System (INIS)

The Ringold Formation consists of lacustrine and fluvial deposits overlying the Columbia River Basalt. The Ringold Formation, because of its thickness, extent, and age, is an excellent unit in which to detect and possibly data the deformation that has occurred since deposition of the basalt. One objective of this study was to investigate the paleomagnetism of the upper Ringold unit exposed at one location in the White Bluffs in enough detail to resolve, with reasonable confidence, the magnetostratigraphy of the rock units sampled. The other objective was to evaluate, in a preliminary manner, the paleomagnetic favorability and magnetostratigraphy of the subsurface Ringold Formation in the Pasco Basin and at selected exposures outside the Pasco Basin. The scope of this study was the collection of 300 paleomagnetic samples, their measurement, and analysis. Samples were collected from the White Bluffs, from core recovered from ...

4

Magnetic field amplification and generation in hypervelocity meteoroid impacts with application to lunar paleomagnetism  

International Nuclear Information System (INIS)

A one-dimensional numerical model for the expansion of impact-produced vapor clouds is used to investigate magnetic field generation mechanisms in events such as meteor collisions with the moon. The resulting cloud properties, such as ionization fraction, electrical conductivity, radial expansion velocity, mass density, and energy density are estimated. The model is initiated with the peak shock states and pressure thresholds for incipient and complete vaporization of anorthosite lunar surface materials by iron and GA composition meteorites. The expansion of the spherical gas cloud into a vacuum was traced with a one-dimensional explicit lagrangian hydrodynamic code. The hypervelocity impact plasmas produced are found to be significant in the amplitudes and orientations of the magnetic fields generated. An ambient magnetic field could have been provided by the core dynamo, which would have interacted with the expanding plasmas and formed induced paleomagnetic ...

1984-03-12

5

The models of experimental magnetic measurements of various biological samples  

International Nuclear Information System (INIS)

Complete text of publication follows. At the Geomagnetic Institute, in the Laboratory for paleomagnetism and archeomagnetism research and at the Geomagnetic Observatory, Grocka (GCK) during the period from November 2004 to February 2008 the researchers carried out experimental magnetic measurements of the total-intensity gradient of the magnetic field vector (changes in the total magnetisation vector) of various biomaterials. Measurements of the gradient total intensity of the magnetic field vector were carried out by GSM-19 magnetometers of high accuracy and recording resolution (accuracy: #DELTA#F=0.1 nT; sampling rate: 1-5 per second). During these experimental biomagnetic measurements samples of water, tissue, blood, cotton, wool, pitch and magnetite-powder were used. In this study, the part of the biomagnetic measurement results relate to the water, blood and tissue. The results of the measurements of gradient total-intensity of the magnetic field for the ...

2009-08-23

6

Dating techniques in fault investigations  

International Nuclear Information System (INIS)

Determining the time of most recent fault movement is an important part of assessing a possible site for a nuclear power plant. The purpose of this paper is not to present research information but to provide a practical guide to some of the dating techniques available to the engineering geologist working on nuclear power plant siting. Emphasis is placed on the practical aspects, such as usable minerals, conditions necessary for them to yield correct dates, degree of accuracy, sample collection, sample size, and sample packaging. In this paper, the usual geologic field techniques are taken for granted (such as those used in stratigraphy, paleontology, and structural analysis) for assessing fault history. Laboratory techniques used in conjunction with or supplemental to field methods are discussed. The specific radiometric methods discussed are "1"4C(carbon-14), fission track, K-Ar (potassium-argon), thermoluminescense, Rb-Sr (rubidium-strontium), and U-Th (uranium-thorium). Racemization ...