undetectable by WBC routine methods. Major Descriptors: *HUMAN POPULATIONS -- RADIATION DOSES; -- HUMAN POPULATIONS Descriptors: BIOASSAY; PLUTONIUM 239; 90; URINE CESIUM 137; POTASSIUM 40; COBALT 60; FALLOUT; *MARSHALL ISLANDS NUCLEAR WEAPONS; QUALITATIVE CHEMICAL ANALYSIS; STRONTIUM t Broader Terms: ACTINIDE ISOTOPES; ACTINIDE NUCLEI; ALKA; ALKALI METAL ISOTOPES; ALKALINE EARTH ISOTOPES; ALPHA DECAY RADIOISOTOPES; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; BETA-PLUS DECAY RADIOISOTOPES; BIOLOGICAL MATERIALS; BIOLOGICAL WASTES; BODY FLUIDS; CESIUM ISOTOPES; CHEMICAL ANALYSIS; COBALT ISOTOPES; DOSES; ELECTRON CAPTURE .RADIOISOTOPES; EVEN-EVEN NUCLEI; EVEN-ODD NUCLEI; HEAVY NUCLEI; INTERMEDIATE MASS NUCLEI; INTERNAL CONVERSION RADIOISOTOPES; ISLANDS; ISOMERIC TRANSITION ISOTOPES; ISOTOPES; LIGHT NUCLEI; MATERIALS; MICRONESIA; MINUTES LIVING RADIOISOTOPES; NANOSEC LIVING RADIOISOTOPES; NUCLEI; OCEANIA; ODD-EVEN NUCLEI; ODD-ODD NUCLEI; PLUTONIUM ISOTOPES; POPULATIONS; POTASSIUM ISOTOPES; RADIOISOTOPES; SPONTANEOUS FISSION RADIOISOTOPES; STRONTIUM ISOTOPES; WASTES; WEAPONS; YEARS LIVING RADIOISOT; YEARS LIVING RADIOISOTOPES Subject Categories: 560101* -- Biomedical Sciences, Applied Studies -Radiation Effects -- Dosimetry & Monitoring -- (1992-) INIS Subject Categories: C5500* -- Personnel Dosimetry & Monitoring 10/5/334 {Item 34 from file: 103) 03281422 EDB-92-044179 Title: ..delta.. sup 18 0 values, sup 87 Sr/ sup 86 Sr and Sr/Mg ratios of Late Devonian abiotic marine calcite: Implications for the composition of ancient seawater Author(s): Carpenter, S.J.; Lohmann, K.C.; Walter, L.M.; Huston, J.G.; Halliday, A.N. (Univ. of Michigan, Ann Arbor (United States)); Holden, P. (Univ. of California, Los Angeles (United States) ) Source: Geochimica et Cosmochimica Acta (United States) v 55:7. Coden: GCACA ISSN: 0016-7037 Publication Date: Jul 1991 p 1991-2010 Document Type: Journal Article Language: In English Journal Announcement: EDB9207 Subfile: ETD (Energy Technology Data Exchange). US DOE Project/NonDOE Project: NP JMT (DOE contractor) Country of Origin: United States Country of Publication: United States Abstract: Late Devonian (Frasnian) abiotic marine calcite has been microsampled and analyzed for {sup 87}Sr/{sup 86}Sr ratios, {delta}{sup 18}0 and {delta}{sup 13}C values, and minor element concentrations. Portions of marine cement crystals from the Alberta and Canning Basins have escaped diagenetic alteration and preserve original marine {delta}{sup 18}0 values ({minus}4.8{per thousand} {plus minus} 0.5, PDB), {delta}{sup 13}C values (+2.0 to +3.0{per thousand}, PDB), {sup Leduc Formation preserve original marine {delta}{sup 18}0 values which are 3 to 4{per thousand} lower than those of modern marine cements. These low {delta}{sup 18}0 values are best explained by precipitation from {sup 18}0-depleted seawater and not be elevated seawater temperature or diagenetic alteration. For comparison with Devonian data, analogous data were collected from Holocene Mg-calcite and aragonite marine cements from Enewetak Atoll, Marshall Islands. Mg-calcite and aragonite marine cements are in isotopic equilibrium with ambient seawater, and Mg-calcite cements are homogeneous with respect to Sr and Mg contents. Comparison of Sr and Mg contents of analogous Devonian and Holocene marine cements suggests that the Mg/Ca ratio of Late Devonian seawater was significantly lower and that the Sr/Ca ratio was significantly higher than that of modern seawater. 9003630 87}Sr/{sup 86}Sr ratios (0.70805 {plus minus} 3), and Sr/Mg weight ratios (0.04 to 0.05). Marine {sup 87}Sr/{sup 86}Sr ratios are globally consistent and can be correlated within the Alberta Basin, and among the Alberta, Canning, and Williston Basins. Correlation of isotopic and chemical data strengthen the conclusion that marine cements from the