摘要:

Black shale and enclosed limestone lenticule from Lower Cambrian Shuijingtuo Formation in the Yangtze Gorge is successfully dated by whole-rock U-Pb method. The results yield a concordant age of about 573 ± 14 Ma, in excellent agreement with both stratigraphic and palaeontologic evidence. The whole-rock U-Pb method can provide a reliable approach for age determination of sedimentary stratum.

ISSN:0021-1915    

DOI:10.1080/10256019008622443

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The paper gives data on isotope composition of interstitial and near-bottom waters sampled in a region of gas-hydrate formation in the Sea of Okhotsk. The studies shows that heavy isotope of oxygen and hydrogen is used in gas-hydrate formation, with the result that isotope composition of its constitution water constitutes δ18O = +1.99‰, δD = +23‰ relatively to SMOW. Formation of autogenic carbonates leads to isotope exchange with interstitial water wich, in turn, changes its primary isotope composition in the direction of increasing of O-18 content. The near-bottom waters are isotope-light relatively to the SMOW standard and to the mean isotope composition of interstitial water in the studied region of gas-hydrate spreading.

ISSN:0021-1915    

DOI:10.1080/10256019008622444

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Concentrations of10Be were measured in 23 lava samples representing historically and14C dated eruptions of major Kurile and Kamchatka volcanoes. We report 2.2–7.9 · 106at/g of10Be for Kuriles and in most cases less than 1.2 · 106at/g for Kamchatka. Thus Kurile segment of the Kurile-Kamchatka arc system features the same isotopic pattern as the Aleutians and some continental arcs like Central America and the Andes. The obtained results confirm previously drawn conclusion that the scale of sediment incorporation in Kurile magmas is not large thought the process itself is quite real.

ISSN:0021-1915    

DOI:10.1080/10256019008622445

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Sorption properties of six different coagulants with respect to the retention of cobalt, caesium, europium and uranium have been studied. The precipitating agents are ferrous sulphate, ferric chloride, aluminium sulphate, tri-sodium phosphate, ferric sulphate and zinc sulphate. The parameters investigated are pH, concentration of the precipitating agents, volume of coagulants vs time and the nature of radionuclides. The data showed that the order of hydroxide volume formed is the following: zinc sulphate > ferric chloride > ferric sulphate > ferrous sulphate, aluminium sulphate, trisodium phosphate. Hexacyanocobaltferrate was used as an adsorbant for caesium from medium-level liquid waste.

ISSN:0021-1915    

DOI:10.1080/10256019008622446

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0021-1915    

DOI:10.1080/10256019008622447

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor