Magnetic properties of microtektites Semiannual status report, 1 Jan. - 31 Jun. 1969

Magnetic susceptibility, magnetization, and Curie constants for normal and bottle-green microtektites found in deep-sea sediment core

Preliminary ultraviolet reflectance of some rocks and minerals from 2000 angstrom to 3000 angstrom

Ultraviolet reflectance measurements of rocks and minerals from 2000 A to 3000

The 57Fe Mossbauer parameters of pyrite and marcasite with different provenances

Eighteen pyrite and twelve marcasite samples which have different provenances have been investigated to determine the systematics of the influence of mineralogical and geological factors on the 57Fe Mossbauer spectra at 298 K. The following results have been obtained: there is no ambiguity in distinguishing single phase pyrite from single phase marcasite by means of 57Fe Mossbauer spectroscopy at 298 K. At 298 K the average electric quadrupole splitting, EQ>, and average isomer shift, , with respect to Fe metal, are 0.6110 +/- 0.0030 mm s-1 and 0.313 +/- 0.008 mm s-1, respectively, for the 18 pyrites; EQ> = 0.5030 +/- 0.0070 mm s-1 and = 0.2770 +/- 0.0020 mm s-1 for the 12 marcasites. At 77 K, [Delta]EQ is 0.624 mm s-1 for pyrite and 0.508 mm s-1 for marcasite. In distinguishing pyrites from marcasites, spectra obtained at 77 K are not warranted.The Mossbauer parameters of pyrite and marcasite exhibit appreciable variations, which bear no simple relationship to the geological environment in which they occur but appear to be selectively influenced by impurities, especially arsenic, in the pyrite lattice. Quantitative and qualitative determinations of pyrite/marcasite mechanical mixtures are straightforward at 298 K and 77 K but do require least-squares computer fittings and are limited to accuracies ranging from +/-5 to +/-15 per cent by uncertainties in the parameter values of the pure phases. The methodology and results of this investigation are directly applicable to coals for which the presence and relative amounts of pyrite and marcasite could be of considerable genetic significance.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24003/1/0000252.pd

Emergence of Antiferromagnetic Correlation in LiTi2-xVxO4 via 7Li NMR

We report 7Li NMR studies of V-substitution effects on spinel oxide superconductor LiTi2O4 (Tc = 13.4 K). In LiTi2-xVxO4 (x = 0-0.4), the V substitution for the Ti site suppressed the relative volume fraction of superconductivity faster than Tc. From the observation of fairly homogeneous enhancement in a 7Li nuclear spin-lattice relaxation rate, we conclude that the V substitution changes electron correlation effects through electron carrier doping from quarter electron filling 3d0.5 to 3d1.5 and then the antiferromagnetic correlation emerges.Comment: 4 pages, 7 figure

United States Geological Survey Reports

Abstract: Tables of decay constants and functions thereof are presented to simplify the problem of calculating the constants involved in the Bateman equation. An alternate method of solving for the amounts of the nth member of a radioactive series is given in the form of a power series

United States Geological Survey Reports

From Abstract: "It is proposed that diffusion be considered as a possible process of isotope fractionation taking place throughout geologic time. Both diffusion in solids and in liquids are considered as possible mechanisms, the latter being more important. Arguments are presented which show that if significant fractionation takes place within a crystal by outward diffusion under solid state conditions, enrichment will be evident only in elements of minor concentration.

United States Geological Survey Reports

Report explaining the theory behind diffusion's effects on isotopic abundance ratios in a sphere

United States Geological Survey Reports

From Abstract: "Age determinations have been made on 21 crystals of gem quality zircon from Ceylon which are believed to have been derived from pegmatites of pre-Cambrian age.

Magnetic study of magnetite in the Tagish Lake meteorite

The saturation magnetization, saturation remanent magnetization, the coercive, and remanent coercive force were determined at room and liquid nitrogen temperatures for three pieces of the Tagish Lake meteorite. The results are compared to similar data for four other chondrites (Allende, Murray, Orgueil, and Murchison). The data suggests that the Tagish Lake meteorite is magnetically homogeneous, and is not as magnetically hard as the comparison chondrites. The magnetization measurements indicate that it contains about 10-11% multi-domain magnetite. Magnetic susceptibility measurements on all the samples from 77 K to room temperature showed a Verwey transition for all the samples which contain a significant amount of multi-domain magnetite. The coercive force data further indicate that the magnetite in Tagish Lake is multi-domain and that the grain size is small and approximately 4-9 micrometers.The Meteoritics & Planetary Science archives are made available by the Meteoritical Society and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

United States Geological Survey Reports

Report discussing a study to calculate the half-life of Th²³² and determine the branching ratio of Bi²¹²