K-Ar and Rb-Sr Dating of blue amphiboles,micas, and associated minerals from the Western Alps   总被引：1，自引：0，他引：1  

Jacqueline Bocquet  Michel Delaloye  Johannes C. Hunziker  Daniel Krummenacher 《Contributions to Mineralogy and Petrology》1974,47(1):7-26

The results of 63 new radiometric K-Ar and Rb-Sr measurements on metamorphic minerals from the internal units of the Western Alps show Hercynian, Permian, as well as three Alpine age groups. The first of the Alpine ages cover the period between 78 and 100 m.y. and refer to high pressure parageneses. The second group comprises K-Ar 39 to 50 m.y. ages; these values are affected by some inherited argon, as indicated by Rb-Sr measurements which point to 35–36±4–5 m.y., i.e. similar to the culmination of the Lepontine crystallization. The final group includes 15 to 30 m.y. ages. It is not yet clear which geologic processes have led to this isotope re-equilibration. Large amounts of inherited argon have been found in Alpine metamorphic minerals of the basement rocks.  相似文献   

The Grader layered intrusion (Havre-Saint-Pierre Anorthosite, Quebec) and genesis of nelsonite and other Fe–Ti–P ores     

Bernard Charlier  Emmanuel Sakoma  Martin Sauv  Kerry Stanaway  Jacqueline Vander Auwera  Jean-Clair Duchesne 《Lithos》2008,101(3-4):359-378

The Grader layered intrusion is part of the Havre-Saint-Pierre anorthosite in the Grenville Province (Quebec, Canada). This intrusion has a basin-like morphology and contains significant resources of Fe–Ti–P in ilmenite and apatite. Outcropping lithologies are massive oxide alternating with anorthosite layers, banded ilmenite–apatite–plagioclase rocks and layered oxide apatite (gabbro-)norites. Drill cores provide evidence for stratigraphic variations of mineral and whole rock compositions controlled by fractional crystallization with the successive appearance of liquidus phases: plagioclase and ilmenite followed by apatite, then orthopyroxene together with magnetite, and finally clinopyroxene. This atypical sequence of crystallization resulted in the formation of plagioclase–ilmenite–apatite cumulates or “nelsonites” in plagioclase-free layers. Fine-grained ferrodiorites that cross-cut the cumulates are shown to be in equilibrium with the noritic rocks. The high TiO₂ and P₂O₅ contents of these assumed liquids explains the early saturation of ilmenite and apatite before Fe–Mg silicates, thus the nelsonites represent cumulates rather than crystallized Fe–Ti–P-rich immiscible melts. The location of the most evolved mineral and whole rock compositions several tens of meters below the top of the intrusion, forming a sandwich horizon, is consistent with crystallization both from the base and top of the intrusion. The concentrations of V and Cr in ilmenite display a single fractionation path for the different cumulus assemblages and define the cotectic proportion of ilmenite to 21 wt.%. This corresponds to bulk cotectic cumulates with ca. 8 wt.% TiO₂, which is significantly lower than what is commonly observed in the explored portion of the Grader intrusion. The proposed mechanism of ilmenite-enrichment is the lateral removal of plagioclase due to its relative buoyancy in the dense ferrodiorite melt. This plagioclase has probably accumulated in other portions of the intrusion or has not been distinguished from the host anorthosite.  相似文献   

Chemical cues released by heterospecific competitors: behavioural responses of native and alien invasive aquatic gastropods     

Jacqueline L. Raw  Nelson A. F. Miranda  Renzo Perissinotto 《Aquatic Sciences - Research Across Boundaries》2015,77(4):655-666

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Identifying key environmental variables shaping within-river fish distribution patterns     

Caroline Senay  Camille Jacqueline Macnaughton  Gabriel Lanthier  Simonne Harvey-Lavoie  Michel Lapointe  Daniel Boisclair 《Aquatic Sciences - Research Across Boundaries》2015,77(4):709-721

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Electro‐Fenton Oxidation of Salicylic Acid from Aqueous Solution: Batch Studies and Degradation Pathway          下载免费PDF全文

Stephy Jacqueline George  Rajan Gandhimathi  Puthiya Veetil Nidheesh  Sreekrishnaperumal Thanga Ramesh 《洁净——土壤、空气、水》2014,42(12):1701-1711

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Statistical analysis of metallic anomaly patterns at former air force bombing ranges     

Jacqueline A. MacDonald  Mitchell J. Small 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(2):203-214

This paper summarizes the findings of a statistical analysis of the locations of metallic anomalies detected at the Pueblo Precision Bombing Range Number 2 in Otero County, Colorado, and at the Victorville Precision Bombing Range in San Bernardino County, California. The purpose of the study is to explore whether statistical properties of the pattern of anomaly locations can be used to discriminate areas likely to contain unexploded ordnance (UXO) left over from previous bombing practice from those unlikely to contain UXO. Techniques for discriminating areas with and without UXO are needed because historic records have left an incomplete account of previous military training activities, so that locations historically used for target practice are often unknown. This study differs from previous research on metallic anomaly data at former military training ranges in that it analyzes the spatial pattern of the discrete locations of the anomalies, rather than the average number of anomalies per unit area. The results indicate that differences in spatial pattern may be a distinguishing feature between areas that were used for target practice and those that are unlikely to contain UXO, even when a large number of ferrous rocks and other inert metallic anomalies are present. We found that at both of the former bombing ranges, the anomaly patterns in sample areas that are distant from all known bombing targets are consistent with a complete spatial randomness pattern, while those near the target areas fit a radially symmetric, bivariate Gaussian pattern. Furthermore, anomaly location patterns generated by surveys with airborne metal detectors have the same statistical properties as the patterns generated by surveys with on-ground detectors, even though the airborne systems detect only a subset of the anomalies found by the ground-based detectors. Thus, pattern information revealed by airborne surveys with metal detectors may be useful in identifying areas where careful searches for UXO are needed.

Jacqueline A. MacDonaldEmail:

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Acid-base activity of live bacteria: Implications for quantifying cell wall charge     

Jacqueline Claessens  Yvonne van Lith  Philippe Van Cappellen 《Geochimica et cosmochimica acta》2006,70(2):267-276

To distinguish the buffering capacity associated with functional groups in the cell wall from that resulting from metabolic processes, base or acid consumption by live and dead cells of the Gram-negative bacterium Shewanella putrefaciens was measured in a pH stat system. Live cells exhibited fast consumption of acid (pH 4) or base (pH 7, 8, 9, and 10) during the first few minutes of the experiments. At pH 5.5, no acid or base was required to maintain the initial pH constant. The initial amounts of acid or base consumed by the live cells at pH 4, 8, and 10 were of comparable magnitudes as those neutralized at the same pHs by intact cells killed by exposure to gamma radiation or ethanol. Cells disrupted in a French press required higher amounts of acid or base, due to additional buffering by intracellular constituents. At pH 4, acid neutralization by suspensions of live cells stopped after 50 min, because of loss of viability. In contrast, under neutral and alkaline conditions, base consumption continued for the entire duration of the experiments (5 h). This long-term base neutralization was, at least partly, due to active respiration by the cells, as indicated by the build-up of succinate in solution. Qualitatively, the acid-base activity of live cells of the Gram-positive bacterium Bacillus subtilis resembled that of S. putrefaciens. The pH-dependent charging of ionizable functional groups in the cell walls of the live bacteria was estimated from the initial amounts of acid or base consumed in the pH stat experiments. From pH 4 to 10, the cell wall charge increased from near-zero values to about −4 × 10⁻¹⁶ mol cell⁻¹ and −6.5 × 10⁻¹⁶ mol cell⁻¹ for S. putrefaciens and B. subtilis, respectively. The similar cell wall charging of the two bacterial strains is consistent with the inferred low contribution of lipopolysaccharides to the buffering capacity of the Gram-negative cell wall (of the order of 10%).  相似文献   

Acid–base activity of microorganisms     

Jacqueline Claessens  Yvonne van Lith  Anniet Laverman  Philippe Van Cappellen 《Journal of Geochemical Exploration》2006,88(1-3):181

In order to distinguish the buffering capacity associated with functional groups in the cell wall from that resulting from metabolic processes, the base or acid consumption of live and dead cells of the Gram-negative bacterium Shewanella putrefaciens was measured as a function of time in a pH stat system. Under neutral (pH 7) to basic (pH 8 and 10) conditions, base neutralization by suspensions of live bacteria beyond 1 h was clearly due to respiratory activity. At pH 4, however, proton neutralization ceased after 50 min due to cell death. Dead cells only produced or consumed protons during the very first minutes after exposure to pH 4, 8 or 10. From the time-dependent acid and base consumption curves of live cells, and the comparison of the acid–base activity of live and dead cells, the charging of ionizable groups in the cell wall was derived. From pH 4 to 10, cell wall charge increases from 0 to about − 4 × 10^− 16 mol cell^− 1.  相似文献   

The trigonometric parallax of the neutron star Geminga     

Jacqueline Faherty  Frederick M. Walter  Jay Anderson 《Astrophysics and Space Science》2007,308(1-4):225-230

We obtained a series of four observations of the isolated neutron star Geminga over an 18 month period using the Advanced Camera for Surveys (ACS) Wide Field Camera (WFC) on the Hubble Space Telescope in order to determine its trigonometric parallax. We find the parallax π=4.0±1.3 mas, corresponding to a distance to Geminga of 250 _?62 ⁺¹²⁰  pc, a result 60% larger than the previously published value. The proper motion is 178.2±1.8 mas/year. In this paper, we describe the analysis techniques in detail since the amplitude of the parallactic shift is smaller than the camera’s pixel size. We fit each star in the images with an appropriate effective PSF and applied a distortion correction to generate stellar positions accurate to 0.01 pixels (～0.5 mas). The 134 stars common to all images serve to establish a reference frame for alignment of the image series. Our observations were made around the times of maximum parallactic shift. We discuss the implications of this new distance measurement for the inferred radius of Geminga, and the neutron star equation of state.  相似文献   

Origin of the giant Allard Lake ilmenite ore deposit (Canada) by fractional crystallization,multiple magma pulses and mixing     

Bernard Charlier  Olivier Namur  Simon Malpas  Cédric de Marneffe  Jean-Clair Duchesne  Jacqueline Vander Auwera  Olivier Bolle 《Lithos》2010,117(1-4):119-134

The late-Proterozoic Allard Lake ilmenite deposit is located in the Havre-Saint-Pierre anorthosite complex, part of the allochtonous polycyclic belt of the Grenville Province. Presently the world's largest Fe–Ti oxide deposit, it had a pre-mining amount in excess of 200 Mt at grades over 60 wt.% hemo-ilmenite. The main ore body is a funnel-shaped intrusion, measuring 1.03 × 1.10 km and 100–300 m-thick. Two smaller bodies are separated by faults and anorthosite. The ore is an ilmenite-rich norite (or ilmenitite) made up of hemo-ilmenite (Hem_22.6–29.4, 66.2 wt.% on average), andesine plagioclase (An_45–50), aluminous spinel and locally orthopyroxene. Whole-rock chemical compositions are controlled by the proportions of ilmenite and plagioclase ± orthopyroxene which supports the cumulate origin of the deposit. Ore-forming processes are further constrained by normal and reverse fractionation trends of Cr concentration in cumulus ilmenite that reveal multiple magma emplacements and alternating periods of fractional crystallization and magma mixing. Mixing of magmas produced hybrids located in the stability field of ilmenite resulted in periodic crystallization of ilmenite alone. The unsystematic differentiation trends in the Allard Lake deposit, arising from a succession of magma pulses, hybridisation, and the fractionation of hemo-ilmenite alone or together with plagioclase suggest that the deposit formed within a magma conduit. This dynamic emplacement mechanism associated with continuous gravity driven accumulation of Fe–Ti oxides and possibly plagioclase buoyancy in a fractionating ferrobasalt explains the huge concentration of hemo-ilmenite. The occurrence of sapphirine associated with aluminous spinel and high-alumina orthopyroxene (7.6–9.1 wt.% Al₂O₃) lacking exsolved plagioclase supports the involvement of a metamorphic overprint during the synchronous Ottawan orogeny, which is also responsible for strong textural equilibration and external granule of exsolved aluminous spinel due to slow cooling.  相似文献