ALBERT

Notes: Graphitization and coarsening of organic material in carbonate-bearing metasedimentary rocks is accompanied by carbon isotope exchange which is the basis of a refractory, pressure-independent geothermometer. Comparison of observed isotopic fractionations between calcite and graphite (δ13CCal–Gr) with independent petrological thermometers provides the following empirical calibration over the range 400–800°C: δ13CCal–Gr= 5.81 times 106×T–2(K) - 2.61. This system has its greatest potential in marbles where calcite + graphite is a common assemblage and other geothermometers are often unavailable. The temperature dependency of this empirical calibration differs from theoretical calibrations; reasons for this are unclear but the new empirical calibration yields temperature estimates in better agreement with independent thermometry from several terranes and is preferred for geological applications.Both calcite-graphite isotopic thermometry and calcite-dolomite solvus thermometry are applied to marble adjacent to the Tudor gabbro in the Grenville Province of Ontario, Canada. The marble has undergone two metamorphic episodes, early contact metamorphism and later regional metamorphism. Values of δ13CCal–Gr decrease regularly from c. 8‰ in samples over 2 km from the pluton to values of 3–4‰ within 200 m of the contact. These samples appear to preserve fractionations from the early thermal aureole with the empirical geothermometer, and indicate temperatures of 450–500° C away from the intrusion and 700–750°C near the gabbro. This thermal profile around the gabbro is consistent with conductive heat flow models. In contrast, the distribution of Mg between calcite and dolomite has been completely reset during later regional metamorphism and yields uniform temperatures of c. 500°C, even at the contact.Graphite textures are important for interpreting the results of the calcite–graphite thermometer. Coarsening of graphite approaching the Tudor gabbro correlates with the decrease in isotopic fractionations and provides textural evidence that graphite crystallization took place at the time of intrusion. In contrast to isotopic exchange during prograde metamorphism, which is facilitated by graphitization, retrogressive carbon isotopic exchange appears to require recrystallization of graphite which is sluggish and easily recognized texturally. Resistance of the calcite–graphite system to resetting permits thermometry in polymetamorphic settings to see through later events that have disturbed other systems.

Notes: This study presents calcite–graphite carbon isotope fractionations for 32 samples from marble in the northern Elzevir terrane of the Central Metasedimentary Belt, Grenville Province, southern Ontario, Canada. These results are compared with temperatures calculated by calcite–dolomite thermometry (15 samples), garnet–biotite thermometry (four samples) and garnet–hornblende thermometry (three samples). Δcal-gr values vary regularly across the area from 〉6.5‰ in the south to 4.0‰ in the north, which corresponds to temperatures of 525 °C in the south to 650 °C in the north. Previous empirical calibration of the calcite–graphite thermometer agrees very well with calcite–dolomite, garnet–biotite and garnet–hornblende thermometry, whereas, theoretical calibrations compare less well with the independent thermometry. Isograds in marble based on the reactions rutile + calcite + quartz =titanite and tremolite + calcite + quartz = diopside, span temperatures of 525–600 °C and are consistent with calculated temperature–X(CO2) relations. Results of this study compare favourably with large-scale regional isotherms, however, local variation is greater than that revealed by large-scale sampling strategies. It remains unclear whether the temperature–Δcal-gr relationship observed in natural materials below 650 °C represents equilibrium fractionations or not, but the regularity and consistency apparent in this study demonstrate its utility for thermometry in amphibolite facies marble.

Notes: Goldfish acclimated for minimum periods of 3 weeks to 5, 15, 25 and 35°C exhibited significant changes in circulating leucocyte types and numbers. Total leucocyte, lymphocyte, neutrophil and eosinophil levels increased significantly between 5 and 25°C, as did their relative contributions to the total leucocyte population. Thrombocyte and blast cell counts increased non-significantly, while variations in monocyte and basophil levels were inconsistent. Between 25 and 35° C, lymphocyte numbers fell sharply, while neutrophil concentrations remained essentially constant as did those of thrombocytes. Response to an intraperitoneally administered mitogen, phytohaemagglutinin, was delayed and reduced at 5° C compared with 25° C.

Notes: As part of the site characterization efforts at Yucca Mountain, Nevada, a series of unsaturated zone tracer tests has been performed at nearby Busted Butte. The phase 2 tracer test was conducted within an instrumented 10 m by 10 m by 7 m in situ block of vitric tuff. A complex tracer solution containing both reactive and nonreactive tracers was pumped into the block during a period of 27 months. Throughout the test, thousands of unsaturated zone pore water samples were collected on sorptive pads attached to inverting membranes and then analyzed for tracer concentration. Partway through the experiment, three new boreholes were drilled into the block, and two intercepted the tracer plume. The rock core was removed for pore water extraction and analysis, and the boreholes were then instrumented with inverting membranes and sorptive pads. The initial set of pore water-soaked pads was removed from the boreholes a week after they were emplaced, and the pore water was extracted and analyzed. This paper compares the tracer concentration data from the rock cores and the pads to evaluate the effectiveness of the inverting membrane collection technique for a variety of tracers. While the sorptive pads sample only dissolved tracers, rock cores contain both dissolved and sorbed tracer. For nonreactive tracers, such as halides (bromide and iodide) and fluorinated benzoic acids (FBAs), this distinction is immaterial, and the rock and pad data agree quantitatively for the halide tracers, and qualitatively for the FBAs. For reactive tracers, such as lithium, the dissolved tracer concentrations can be estimated from rock analyses by dividing by the tracer's retardation factor; when this correction is applied, the rock and pad lithium data are also in reasonable agreement.