All issues
Volume 14 (1980)
- Issue 6 Pages 259-
- Issue 5 Pages 203-
- Issue 4 Pages 145-
- Issue 3 Pages 101-
- Issue 2 Pages 63-
- Issue 1 Pages 1-
Volume 14, Issue 2
Displaying 1-5 of 5 articles from this issue
- |<
- <
- 1
- >
- >|
-
Keisuke Nagao, Nobuo Takaoka, Hiroshi Wakita, Sadao Matsuo, Naoyuki Fu ...1980 Volume 14 Issue 2 Pages 63-69
Published: April 20, 1980
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSElemental and isotopic compositions of rare gases in gas samples from “Helium spots” and CO2-spring in the fault zone formed by the Matsushiro earthquake swarms, reported by WAKITA et al. (1978), have been analyzed mass spectrometrically. Isotopic compositions of rare gases were atmospheric except for 3He/4He and 40Ar/36Ar ratios. 3He/4He ratios were (9.12 ± 0.58) × 10-6 and (9.10±0.69) × 10-6, and 40Ar/34Ar ratios were 308 ± 9 and 304 ± 8 for “Helium spots” and CO2-spring, respectively. Rare gas elemental abundance patterns for both samples were similar to a pattern produced by the dissolution equilibrium of atmospheric rare gases in water. The origin of rare gases is discussed. The 3He/4He ratio found in the fault zone suggests that the systematic observation of 3He/4He ratio may be useful for the detection of precursory phenomena of an earthquake.View full abstractDownload PDF (1645K) -
J. A. J. Thompson, R. W. Macdonald, C. S. Wong1980 Volume 14 Issue 2 Pages 71-82
Published: April 20, 1980
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSLevels of total mercury in marine sediments were surveyed in Howe Sound, a fjord near Vancouver, B.C., receiving mercury-contaminated discharges from a chlor-alkali plant since 1965. Similar mercury levels were found in the marine sediments in an area of 15.5km2 near the plant for the periods 1972-3 and 1976-7, despite a drastic cut in mercury input by the plant in recent years and a decrease in mercury contents of sediments adjacent to the dock of the chlor-alkali plant. Methylmercury contents were found to be less than 1 percent of the total amount of mercury in the surface marine sediment. Mechanisms of mobilization are discussed. These processes appeared to be rather slow and could not significantly alter the mercury budget in the upper Howe Sound sediment.View full abstractDownload PDF (2740K) -
M. Honda, K. Horie, M. Imamura, K. Nishiizumi, N. Takaoka, K. Komura1980 Volume 14 Issue 2 Pages 83-89
Published: 1980
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSCosmogenic nuclides have been studied in the Kirin chondrite (H5). Some experimental results obtained in samples sent to us (Nos. 1 and 4 fragments) are described. We measured the gamma rays of 50Mn, 26Al, 22Na and 60Co, using Ge(Li) detector systems. 53Mn was determine by an activation method based on 53Mn(n, γ)54Mn. The light rare gases were also measured by a mass spectrometer in one of the specimens. We compare our data with others and conclude that it is possible to read out the fossil records in the meteorite and interpret them by, 1) Multiple exposure history and 2) Depth effects in the production of cosmogenic nuclides in different geometries.View full abstractDownload PDF (1400K) -
Kazuo Sato, Ichiro Kaneoka, Jun Sato1980 Volume 14 Issue 2 Pages 91-94
Published: April 20, 1980
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSA basaltic rock sample heated up to 1, 300° releases only a part of the total Rn, whereas substantial fractions of the other rare gases are expelled at lower temperatures. The experimental results obtained for Rn release are considerably different from the observations on the 236Ra-222Rn disequilibrium in fragments of erupting magmas, which generally show much greater Rn-releasing efficiencies. The role of major volatile components in the degassing of felsic magmas is discussed.View full abstractDownload PDF (739K) -
Kent C. Condie, Douglas G. Brookins1980 Volume 14 Issue 2 Pages 95-99
Published: April 20, 1980
Released on J-STAGE: April 08, 2008
JOURNAL FREE ACCESSCompared to average Precambrian shield, the average Precambrian terrane in New Mexico contains more Si, K, Rb, U and REE and less Fe, Ti, Al, Mg, Ca, Cr, Ni, Co, Sr, Zr, and Ba. It also is characterized by a less fractionated light REE pattern, a larger negative Eu anomaly, larger Ba/Sr and Rb/Sr ratios, a smaller K/Rb ratio, and larger heat productivity. The lower crust in New Mexico is more depleted in K, Th, U, and related LIL elements than the crust beneath average Precambrian shield. Such depletion may be explained by transfer of LIL elements from deep to shallow crustal levels by rising granites that are produced by partial melting of the lower crust.View full abstractDownload PDF (1136K)
- |<
- <
- 1
- >
- >|