郯庐断裂带鲁皖段新生代玄武岩形成机制的稀土判别

根据郯庐断裂带鲁皖段早第三纪、中新世以及更新世玄武岩的稀土元素特征的研究，应用稀土判据探讨了区内玄武岩的形成机制。稀土元素和常量元素的相关关系显示，郯庐断裂带新生代3个阶段玄武岩成岩过程中分离结晶作用不明显，其形成机制应该为上地幔部分熔融作用。通过多种稀土元素联合协变关系也同样反映了这些玄武岩的形成机制为上地幔部分熔融作用，同时也显示区内新生代玄武岩的稀土元素特征继承了其源区物质的稀土元素特征。这一结论与区内Sr，Nd同位素研究的结果相吻合。     

Separation of iron/III/ from manganese/II/ in basalts by solvent extraction

The separation of iron/III/ from manganese/II/ by solvent extraction from hydrochloric acid to the chloroform solution of acetylacetone was applied to the analysis of basalts. The results after single and double separation of iron/III/ from manganese/II/ in basalts are presented.     

Determination of rare earth elements in rocks and meteorites by the radioactivation method

Methods of digestion of samples by acidic dissolution and in fused sodium peroxide were modified in conformity with the chemical composition of basalts, periotites and stone meteorites as well as the method of REE pre-concentration by the lanthanum fluoride cycle. The enriching methods were used for the neutron-activation determination of the individual rare-earth elements in rocks and meteorites with a sensitivity up to 10⁻⁸%.     

Potential for microbial growth in arid subsurface sediments

To determine if bacterial populations could be increased for bioremediation of contaminants, the microbial growth arising in 200 h from the solid material from the vadose zone at an arid site after addition of water and nutrients was determined. Initial bacterial populations and activities at the site were very low. Bacteria grew in the interbed sands and silts with the higher carbon contents (0.08–1.1%), but did not respond in the basalts and interbed material with lower carbon content (undetectable). In longer term studies, to 30 d, there was evidence for bacterial activity in less than 25% of either the basalts or interbed material.

     

Determination of major, minor and trace elements in rock samples by laser ablation inductively coupled plasma mass spectrometry: Progress in the utilization of borate glasses as targets

The present work is a continuation of a research study performed at our laboratory aiming at the multielement analysis of rock samples (basalts and shale) by inductively coupled plasma mass spectrometry in combination with laser ablation using borate glasses as analytical targets. Argon, nitrogen-argon mixtures and helium were evaluated as cell gases, the latter confirming its better performance. Different operational parameters of the laser, such as gas flow, energy, focus, scanning speed and sampling frequency were optimized. External calibration was made with standards prepared by fusion of geological reference materials (basalts 688 and BCR-2, obsidian SRM 278, and shale SGR-1) of different mass fractions in the meta-tetra borate matrix. Coefficients of determination (R²) were > 0.99 for 30 elements from o total of 40 determined. Method validation was then performed using additional certified reference materials (BHVO-2, BIR-1, SCo-1) produced as borate targets in a similar way. Accuracies were better than 10% for most of the elements studied and analytical precisions, calculated from the residual standard deviations of calibration curves were, typically, between 6% and 10%. Additionally, the semiquantitative TotalQuant® technique was applied, which gave, within the expected uncertainty for this calibration technique, concordant results when compared to the quantitative external calibration procedure. Both methods were then used for the analysis of marine shale samples, which are of great geological interest in petroleum prospecting.     

Determination of boron and other elements in volcanic rocks by prompt gamma-ray analysis: An application to magma genesis in Kyushu island,SW-Japan

Neutron induced prompt gamma-ray activation analysis (PGAA) is applied for determining boron contents in volcanic rocks, which is an important element in the discussion of material circulation in volcanic arc systems. To evaluate the recycling of oceanic crust in Kyushu, we analyzed boron and other trace element contents in basaltic rocks from the area. The basalts from volcanic front have high B/Nb (2.9–3.7), B/Zr (0.1–0.2) and B/Sm (2.8–6.0) ratios, whereas those ratios in the basalts from backarc are extremely low (<0.5; <0.1; 0.5–1.7), respectively. This indicates that the recycling of subducted oceanic crust to the arc crust is limited in the volcanic front.     

土壤发育过程中稀土元素的地球化学指示意义

研究了海南岛北部不同时期喷发的玄武岩上发育土壤中稀土元素的地球化学特征和行为,探讨成土元素的分异及其对土壤发育程序的指示作用。ＲＥＥ总量与成土年龄呈显著正相关,是指示土壤发育程序的良好指标。同时,随土壤发育程度的加深,ＲＥＥ出现分异,土壤中轻稀土逐渐富集,重稀土亏损,伴随的进一步发育,Ｃｅ逐渐向正异常而Ｅｕ向负异常方向演化。     

Chemical fractionation in the solar system

The cosmochemical and geochemical history of planetary material is reflected in relative and absolute abundances of two groups of trace elements; siderophiles and volatiles. Many of these elements can be determined at the requires levels only by radiochemical neutron activation analysis. The abundance patterns of elements in chondritic meteorites result from condensation processes in the solar nebula. The composition of planetisimals which bombarded the Moon is characterized from trace elements in lunar breccias, and is also related to nebula processes. Trace elements in anorthosites and basalts from Earth and Moon suggest that the Moon is refractory-rich and volatile-poor relative to the Earth.     

DISTINGUISHING OF TWO VOLCANIC ROCK SERIES IN THE LANCANG GROUP, YUNNAN PROVINCE, SW CHINA AND ITS GEOLOGICAL IMPLICATION

The detailed study on petrochemistry and geochemistry shows that meta-volcanics from Huimin and meta-basalts from Suyi belong, respectively, to different volcanic series. The former is of non-alkalic volcanic series and the latter is of straddle A-type alkslic series. Based on their geochemical characteristics of REE, LIL, HFS and Nd, Sr isotope elements, we suggest that Huimin volcanics were formed in an island arc setting and Suyi basalts were formed in a back-continental arc extensive setting. These two volcanic series have not petrogenic relationship.     

Activation analysis as a geochemical tool: Statement of its capabilities for geochemical trace element studies

The capabilities of neutron activation for trace elements geochemical investigation are demonstrated on the basis of long term determination and intercomparisons for the purpose of geochemical oceanic basalts investigations. We illustrate by a few examples the necessity of these capabilities for precise petrological and geodynamical modelizations. Hygromagmaphile trace element fingerprints of mantle heterogeneities are emphasized.     

Thermoanalytical investigation of cavity filling natrolite group minerals in basalts

Cavity filling natrolites in basalts from several localities of Balaton Highland were investigated by different methods. The measurements of different thermal parameters (corrected decomposition temperature and activation energy) were first applied for natrolite. Energy dispersive spectroscopy (EDS) was used for the observation of chemical composition. Few of the minerals are regular, ordered natrolite, the majority proved to be so called ‘tetranatrolite’. According to our observations both natrolite and ‘tetranatrolite’ may appear in the same locality and chemical inhomogenity can be demonstrated within a single natrolite needle.     

Determination of ultra-trace rare earth elements in chondritic meteorites by inductively coupled plasma mass spectrometry

A method for the direct determination of ultra-trace rare earth elements (REE) in seven Chinese chondritic meteorites by inductively coupled plasma mass spectrometry (ICP-MS) was developed. Samples were digested with a mixture of HF+HNO₃ acids in Teflon pressure bomb. The accuracy and precision of the method were assessed by the analysis of four standard reference materials including one chondrite (Allende) and three basalts (BCR-1, BHVO-1 and W-2), the results obtained in this study agree quite well with the recommended values. The reproducibilities (expressed as RSD) of samples were less than 5%.     

TRANSITIONAL FIELD BEHAVIOUR FOR THE MATUYAMA-BRUNHES

Paleomagnetic study from Tongjing basalts, Shandong Province, China, provides a record of the transitional field behaviour for the Matuyama-Brunhes. Based on the record the transitional field configurations are studied. The reasons that make the virtual geomagnetic pole (VGP) at the low latitude are researched.     

Biotechnology of Cr(VI) transformation into Cr(III) complexes

The dose-dependent formation of Cr(III) complexes and uptake of chromium by Arthrobacter oxydans — a Gram-positive bacterium from contaminated Columbian basalt rocks (USA) — were studied along with the testing under aerobic conditions of two bacterial strains of Arthrobacter genera isolated from the polluted basalts from the Republic of Georgia. Instrumental neutron activation analysis (INAA) was used to track the accumulation of chromium in the bacterial cells. To monitor and identify Cr(III) complexes in these bacteria, electron spin resonance (ESR) spectrometry was employed.     

The determination of bromine in rocks by neutron activation analysis

A neutron activation method for the determination of bromine in rocks and minerals is described. After removal of iodine, bromine is separated by oxidation with potassium permanganate and extraction with carbon tetrachloride. Bromine is thon precipitated as silver bromide; yields are from 60 to 84%. The method has a sensitivity of 0.001 p.p.m. of bromine and is free from interfering reactions. The values obtained for G-1 and W-1, 0.484 and 0.490 p.p.m. of bromine respectively, are lower than the average values for granites and basalts previously reported.     

Zur Anwendung der Neutronenaktivierungsanalyse bei der Untersuchung basaltischer Gesteine ozeanischer und kontinentaler Herkunft

INAA was used to obtain genetic informations on basalts through their weathering and sedimentary products. The rare earths content of the samples could be determined with sufficient accuracy without radiochemical separation using routine computer programs. Basalts of different tectonic setting could be distinguished by their rare earths, thorium and uranium contents. Relations between magmatic rock fragments and sedimentary environment (including manganese nodules) of the Romanche Zone (Atlantic) are discussed.     

Thermal and Sintering Behaviour of Basalt Glasses and Natural Basalt Powders

A study of three Spanish and one Bulgarian basaltic rock demonstrated that, after thermal treatment at temperatures higher than 800°C, crystallization of pyroxenes, anorthite and magnetic occurred. Following sintering of the original basalts and powdered original glasses, the same crystalline phases were nucleated and grown in the resulting glass-ceramics. Chemical and DTA/TG analyses suggested similar behaviour for the synthesized Canarian basalt glasses, which are located in the tephrite-basanite field, and different behaviour for the trachy-andesite Canarian and the basaltic-andesite Bulgarian basalt glass. In consequence of the high sensitivity of the specific heat to phase transformations, C_p(T) and TMA experiments allowed a distinction between the tephrite-basanite and trachy-andesite Canarian glasses on the basis of their different thermal behaviour. This revised version was published online in August 2006 with corrections to the Cover Date.     

Sorption of cesium on rocks using heterogeneity-based isotherm models

Summary Sorption of radionuclides onto surrounding rocks play an important role in retarding the migration of radionuclides from a radioactive waste repository. The sorption isotherm model is usually used to describe the sorption behaviors and assess the sorption potential of radionuclides on rock. However, most of the studies to investigate the feasibility of isotherm models for the sorption of radionuclides are based on the assumption that the sorption energy is uniform and homogeneously distributed on the sorbent surfaces. In this study, two heterogeneity-based isotherms, Langmuir-Freundlich isotherm model (LF) and generalized-Freundlich isotherm model (GF), were used for the evaluation of the sorption characteristics of cesium on the selected Taiwan tuff and basalt. The sorption experiments in this study were carried out by batch method, and the experimental data were modeled by LF and GF heterogeneity-based isotherm models. The results showed that both of the LF and GF models could fit the data more perfectly than the Langmuir model. The heterogeneity of sorption onto tuff and basalt could be well characterized by the LF and GF models by means of the calculation and plotting of the affinity spectrum. The results showed that the sorption surface of tuff is more heterogeneous and complex than that of basalts.     

Acid digestion of geological and environmental samples using open-vessel focused microwave digestion

The application of open vessel focused microwave acid digestion is described for the preparation of geological and environmental samples for analysis using inductively coupled plasma-mass spectrometry (ICP-MS). The method is compared to conventional closed-vessel high pressure methods which are limited in the use of HF to break down silicates. Open-vessel acid digestion more conveniently enables the use of HF to remove Si from geological and plant samples as volatile SiF4, as well as evaporation-to-dryness and sequential acid addition during the procedure. Rock reference materials (G-2 granite, MRG-1 gabbros, SY-2 syenite, JA-1 andesite, and JB-2 and SRM-688 basalts) and plant reference materials (BCR and IAEA lichens, peach leaves, apple leaves, Durham wheat flour, and pine needles) were digested with results comparable to conventional hotplate digestion. The microwave digestion method gave poor results for granitic samples containing refractory minerals, however fusion was the preferred method of preparation for these samples. Sample preparation time was reduced from several days, using conventional hotplate digestion method, to one hour per sample using our microwave method.     

H2O‐δD‐FeIII relations of dehydrogenation and dehydration processes in magmatic amphiboles

Stable isotope compositions of a suite of magmatic amphiboles from alkaline basalts and andesitic rocks were examined to constrain the effects of degassing processes on the hydrogen isotope compositions. The Fe³⁺ (as Fe³⁺/Fe_total) and H₂O contents, as well as the H isotope compositions of the amphiboles, differ markedly (27–58%, 0.5–2.2 wt%, ?107 to ?15‰, respectively) but indicate systematic variations. The observed trends can be explained either as dehydrogenation or dehydration processes, both of which are coupled to oxidation processes, the latter most probably related to O^2? substitution within amphiboles. The dehydrogenation‐dehydration models can be used to assess the primary compositions of the magmas. As an important example, δD values of amphiboles of Martian meteorites are discussed in a similar context. Copyright © 2006 John Wiley & Sons, Ltd.