Towards a Method for Quantitative LA‐ICP‐MS Imaging of Multi‐Phase Assemblages: Mineral Identification and Analysis Correction Procedures

Here, we present an approach to laser ablation ICP‐MS mapping of multi‐phase assemblages that permits the use of different internal standard elements, concentration values and reference materials for each mineral. In this way, we obtain not only broad pictures of elemental distributions within samples but can also extract high accuracy concentration data for any user‐selected region. This is accomplished by assigning regions of an image to corresponding mineral phases on a pixel‐by‐pixel basis. In this way, accurate trace element concentrations can be determined for each mineral phase, despite potential variations in their ablation characteristics. We present an example where elemental maps are constructed from ablation of a gabbroic sample that includes the phases apatite, amphibole and plagioclase. This work represents an important first step towards development of a method to produce highly accurate LA‐ICP‐MS elemental maps of multi‐phase samples.     

Spatial Geochemistry: A Characterisation of Heterogeneity in Reference Materials

Geochemical reference materials (RMs) for microbeam techniques are typically characterised by averages and dispersion statistics (e.g., standard deviation, variance) that are calculated for a number of measurements (beam shots). It is proposed that the mapping of RMs will add spatial information that better characterises the grouping and magnitudes of the heterogeneities and provides the information necessary to define a minimum analytical mass. A simple mathematical solution is proposed, which can be easily computed and understood. The analogous notions to sill and range from geostatistics are applied to the minimum analytical mass versus the relative standard deviation. To assess grouping and magnitudes of the heterogeneities, a ‘proximity number’ is computed for each average value ± ‘n’ standard deviations (magnitude). Different chemical anomalies have been simulated to demonstrate the behaviour of the proximity number. To further test the proposed spatial geochemistry concept, sulfide‐ and oxide‐bearing RMs have been selected because many are crippled with nugget effect. They have been mapped with a micro‐XRF apparatus, and results are presented for CHR‐Bkg, CHR‐Pt+, MASS‐1, MASS‐3, WMS‐1 and WMS‐1a. MASS‐1 and MASS‐3 are the most suitable RMs for microbeam techniques. Spatial geochemistry offers a new approach to better characterise reference materials.     

Iron Distribution in Size‐Resolved Aerosols Generated by UV‐Femtosecond Laser Ablation: Influence of Cell Geometry and Implications for In Situ Isotopic Determination by LA‐MC‐ICP‐MS

The influence of ablation cell geometry (Frames single‐ and HelEx two‐volume cells) and laser wavelength (198 and 266 nm) on aerosols produced by femtosecond laser ablation (fs‐LA) were evaluated. Morphologies, iron mass distribution (IMD) and ⁵⁶Fe/⁵⁴Fe ratios of particles generated from magnetite, pyrite, haematite and siderite were studied. The following two morphologies were identified: spherules (10–200 nm) and agglomerates (5–10 nm). Similarity in IMD and ablation rate at 198 and 266 nm indicates similar ablation mechanisms. ⁵⁶Fe/⁵⁴Fe ratios increased with aerodynamic particle size as a result of kinetic fractionation during laser plasma plume expansion, cooling and aerosol condensation. The HelEx cell produces smaller particles with a larger range of ⁵⁶Fe/⁵⁴Fe ratios (1.85‰) than particles from the Frames cell (1.16‰), but the bulk aerosol matches the bulk substrate for both cells, demonstrating stoichiometric fs‐LA sampling. IMD differences are the result of faster wash out of the HelEx cell allowing less time for agglomeration of small, low‐δ ⁵⁶Fe particles with larger, high‐δ ⁵⁶Fe particles in the cell. Even with a shorter ablation time, half the total Fe ion intensity, and half the ablation volume, the HelEx cell produced Fe isotope determinations for magnetite that were as precise as the Frames cell, even when the latter included an aerosol‐homogenising mixing chamber. The HelEx cell delivered a more constant stream of small particles to the ICP, producing a more stable Fe ion signal (0.7% vs. 1.5% RSE for ⁵⁶Fe in a forty‐cycle single analysis), constant instrumental mass bias and thus a more precise measurement.     

Preparation and Characterisation of Two Geochemical Reference Materials: DG‐H (Granite) and AM‐H (Amphibolite) from the Himalayan Orogenic Belt

Two geochemical reference materials of Himalayan origin named DG‐H (a granite) and AM‐H (an amphibolite) prepared by the Wadia Institute of Himalayan Geology Dehradun are described. Both samples were collected from the NW Himachal Himalaya in India. With the participation of analysts from more than forty international laboratories, element determination data collected during the past 10 years for characterisation of the samples was processed to assign working values using statistical procedures in use for this purpose. Earlier work published on these samples is incorporated in the present communication making it an updated document. The typical chemical and petrological characteristics of these two samples may prove useful for method validation and calibration of analytical instruments used for analysing similar rock types, and for widening the analytical range of several analytical methods used for geochemical analysis.     

平朔矿区安太堡煤矿9^#煤的有机地球化学特征

9^#煤是安太堡煤矿的主要可采煤层之一,宏观煤岩类型为半暗型煤。通过对煤中可溶有机质成分特征及饱和烃、芳香烃中各项生物指标化合物含量进行分析,得出：（1）样品中较高的芘含量反映煤样中的成煤母质中陆源高等植物占优势;（2）OEP指数和芳香烃中MPI指数均呈现低值,指示有机质的成熟度较低;（3）Pr/Ph值变化较大,氧芴含量稍高,指示成煤环境海侵频繁,氧化还原沉积环境交替。     

Radio observations of comet 9P/Tempel 1 with the Australia Telescope facilities during the Deep Impact encounter

We present radio observations of comet 9P/Tempel 1 associated with the Deep Impact spacecraft collision of 2005 July 4. Weak 18-cm OH emission was detected with the Parkes 64-m telescope, in data averaged over July 4–6, at a level of  12 ± 3 mJy km s⁻¹  , corresponding to OH production rate  2.8 × 10²⁸  molecules s⁻¹ (Despois et al. inversion model, or  1.0 × 10²⁸ s⁻¹  for the Schleicher & A'Hearn model). We did not detect the HCN 1–0 line with the Mopra 22-m telescope over the period July 2–6. The 3σ limit of 0.06 K km s⁻¹ for HCN on July 4 after the impact gives the limit to the HCN production rate of  <1.8 × 10²⁵ s⁻¹  . We did not detect the HCN 1–0 line, 6.7 GHz CH₃OH line or 3.4-mm continuum with the Australia Telescope Compact Array (ATCA) on July 4, giving further limits on any small-scale structure due to an outburst. The 3σ limit on HCN emission of 2.5 K km s⁻¹ from the ATCA around impact corresponds to limit < 4 × 10²⁹ HCN molecules released by the impact.     

刺参(Apostichopus japonicus)高温胁迫应答基因应激表达特性的分析

采用实时荧光定量PCR技术对刺参高温胁迫抑制性消减cDNA文库中2个上调表达差异基因hsp70和l(2)efl,2个下调表达差异基因pcsk9和myp,在不同温度、不同胁迫时间以及不同组织中的应激表达特性进行了分析.在15-30℃范围内,温度越高hsp70和l(2)efl基因相对表达量越多;而pcsk9、myp基因随着温度升高其表达量下降.在30℃高温胁迫0-3h时间内,hsp70表达量的变化最为显著,表现为先升后降再升;l(2)efl在1h后开始明显的上调表达,在2.5h之后呈下降趋势;pcsk9和myp基因表现为表达下调,表达量最小值分别在3h和2h.常温下hsp70、l(2)efl和pcsk9均在体壁中的表达量最高,在呼吸树中表达量最少,myp在消化道中表达量最高,在纵肌中表达量最少;高温胁迫后hsp70、l(2)efl均在呼吸树中上调表达量变化最显著;pcsk9和myP分别在呼吸树和纵肌中下调表达量变化最显著.这4种基因通过表达产物量的变化或作为功能蛋白直接参与代谢调节,或作为调节蛋白调控胁迫功能蛋白的表达及活性来提高刺参对高温胁迫的耐受能力.     

Design and Implementation of the Hydrographic Production and Management Information System (HYPAMIS)

With the development of hydrographic work and information techniques, the traditional work mode is not suitable for the Chinese Marine Safety Administration Bureau (CMSAB). Aiming at the separation of charts production and management, a new idea that is the integration of production, management, and quality control is presented. Geographic Information System (GIS), Management Information System (MIS), Office Automation (OA) and Spatial Database Management (SDM) advanced techniques are introduced into the workflows in CMSAB. To realize information sharing, a mixed mode with Browser/Server (B/S) mode and Client/Serve (C/S) mode are adopted. Based on the above ideas and strategies, an integrated system named Hydrographic Production And Management Information System (HYPAMIS) was developed. The whole workflow and three subworkflows including survey management workflow, production workflow, and quality control workflow of are outlined after re-engineering the CMSAB organization. Some design principles and key techniques of the HYPAMIS including the cooperation of GIS and MIS, object-oriented spatial data model and management, data management based on database, and security control are illustrated in detail. Then the implementation of the system is introduced briefly. Finally, performance evaluation of the system and future work is given.     

Late Quaternary palaeoenvironment of northern Guatemala: evidence from deep drill cores and seismic stratigraphy of Lake Petén Itzá

Long sediment cores were collected in spring 2006 from Lake Petén Itzá, northern Guatemala, in water depths ranging from 30 to 150 m, as part of an International Continental Scientific Drilling Program project. The sediment records from deep water consist mainly of alternating clay, gypsum and carbonate units and, in at least two drill sites, extend back >200 kyr. Most of the lithostratigraphic units are traceable throughout the basin along seismic reflections that serve as seismic stratigraphic boundaries and suggest that the lithostratigraphy can be used to infer regional palaeoenvironmental changes. A revised seismic stratigraphy was established on the basis of integrated lithological and seismic reflection data from the basin. From ca 200 to ca 85 ka, sediments are dominated by carbonate‐clay silt, often interbedded with sandy turbidites, indicating a sediment regime dominated by detrital sedimentation in a relatively humid climate. At ca 85 ka, an exposure horizon consisting of gravels, coarse sand and terrestrial gastropods marks a lake lowstand or partial basin desiccation, indicating dry climate conditions. From ca 85 to ca 48 ka, transgressive carbonate‐clay sediments, overlain by deep‐water clays, suggest a lake level rise and subsequent stabilization at high stage. From ca 48 ka to present, the lithology is characterized by alternating clay and gypsum units. Gypsum deposition correlates with Heinrich Events (i.e. dry climate), whereas clay units coincide with more humid interstadials.