The southern San Joaquin Valley contains more than 7 km of sedimentary fill, largely Miocene and younger in age. Ancient depositional environments ranged from alluvial fans at the basin margins to turbidite fans toward the basin center. Mixed-layer illite/smectite (I/S) dominates the <2-μm fraction of Miocene shales, and kaolinite is abundant in Miocene sandstones. I/S from carbonate-cemented sandstones contains 5–20% more smectite layers than I/S from uncemented sandstones. The timing of cementation correlates with the proportion of smectite layers in the I/S, suggesting that cementation slowed the illitization process. Smectite and I/S with > 80% expandable layers occur at present burial temperatures of 120°-l 40°C in Miocene sandstones and shales. This highly expandable I/S is restricted to areas covered by thick deposits (1000-2500 m) of Pleistocene sediments. Rocks of similar age and at equivalent temperatures, but covered by <900 m of Pleistocene sediments, contain I/S having low expandabilities (<30%).

Microprobe analyses of 16 discrete smectite and smectite-rich I/S clays indicate an average montmorillonite composition of:

$$\left( {C{a_{0.2}}{K_{0.15}}N{a_{0.1}}} \right)\left( {A{l_{3.0}}F{e^{3 + }}_{0.35}M{g_{0.75}}T{i_{0.03}}} \right)\left( {S{i_{7.7}}A{l_{0.3}}} \right){O_{20}}{\left( {OH} \right)_4} \cdot n{H_2}O.$$

Residence time at different temperatures appears to be an important influence on the percentage of smectite layers in I/S from the San Joaquin basin. Areas containing I/S with high expandabilities (e.g., 95% smectite layers) have a time-temperature index (TTI) of 4.0-4.5 at 120°C, whereas areas containing I/S with low expandabilities (e.g., 30% smectite layers) have a TTI of 5.0. Present data suggest that highly expandable I/S changed to slightly expandable I/S over a narrow temperature interval (10°-20°C). Differences in the potassium availability from detrital components and in the K+/H+ activity ratios of pore water do not appear to be related to the differences in the percentage of smectite layers of these I/S clays.

The porosity of a propylitized granite from Charroux (France), with no fractures or sealed fractures, increases by more than four times from the unaltered (0.3%) to the altered rock (1.4%). This evolution results from several local porosity modifications which occur at different scales in the rock: (1) at the core scale, from 10−1 to 10−5 m, where rock porosity changes as a function of rock-forming mineralogical composition; (2) at the mineral scale, from 10−3 to 10−7 m, where porosity depends both on the nature of the rock-forming mineral and its clay mineral alteration. Mineralogical and porosity data collected from the granite using a mineralogical map (after chemical staining and scanning electron microscopy images combined with autoradiographs) indicate that (1) the ferromagnesian rock-forming minerals — biotite and magnesiohornblende — act as the main porosity source in the unaltered granite, and (2) the nature of the clay minerals replacing rock-forming minerals in the altered granite appears to control the porosity value through two major alteration processes: chloritization and phengitization which affect the ferromagnesian minerals and produce non-porous chloritic and porous phengitic areas, respectively, at the studied scales. The observation that incipient porosity formation in granites is strongly linked to the pathway of ferromagnesian silicate alteration and subsequent clay mineral formation underlines the need to study parent-rock texture and mineralogy and their effects on subsequent near-surface weathering of granites.

Measurements of highly radioactive actinides such as Np, Pu, Am, or Cm in as-fabricated or irradiated nuclear fuels are crucial to improve the safety and performance of the nuclear fuel cycle, but also necessary to find solutions to the environmental impact of long-lived actinides in nuclear waste. Currently, the most common technique of measuring the quantity and distribution of actinides in nuclear fuel is electron probe microanalysis (EPMA). However, the accurate analysis of actinides by EPMA is accompanied by numerous obstacles such as interferences in the M-line X-ray region, absorption edges, and the lack of reference materials. Therefore, the measurement protocol of radioactive and irradiated samples requires further investigation and most importantly facilitation. Here, we establish a guideline for precise quantification of actinide elements (Th, U, Np, Pu, Am, and Cm) in fabricated or spent nuclear fuels. For this purpose, we have characterized actinide-bearing reference samples to visualize spectral interferences, list peak, and background positions and employ the standardless calibration curve method for the measurements of Am and Cm. This newly derived analytical protocol was successfully tested on an irradiated fuel sample and can be now implemented as an improved guideline for the quantification of actinides.

A new procedure is described for locating mineral grains in geological samples prepared for microprobe analysis. This procedure uses a digital image of the entire sample surface to select points of interest. These features of interest must be visible in this external image. Once the sample is mounted on the specimen stage of the microprobe, the digital image is used as a ‘map’ to relocate minerals for analysis. The image can be recorded using either a video camera, fitted with a macro zoom lens, or a flat-bed scanner. A calibration procedure has been developed in which two indexing points are used to calculate the instrument stage coordinates from the pixel coordinates of the digital image. Following this calibration, the stage coordinates of any feature visible in the digital image can be displayed to facilitate rapid relocation. The procedure was evaluated by relocating magnetite grains visible in an optical image of a geological thin section. The repositioning accuracy in relocating 28 magnetite grains distributed over an area of about 20 × 30 mm was found to be 157 ± 102 µm (one standard deviation) from the video camera image and 48 ± 28 µm from a flat bed scanner image. The former image was thought to suffer from some optical distortion. The procedure may be applied to any microprobe instrument fitted with a digital x-y specimen stage. Future applications in relocating features visible in autoradiographs are currently being evaluated.

Högbomite is reported from two upper-amphibolite and granulite-facies, sapphirine-bearing, Al–Mg–Fe-rich and silica-poor lens-shaped layers within the Bamble Sector, south Norway. Primary assemblages, indicating peak metamorphic conditions of 773-844°C at 7 kbar (Mg–Fe exchange thermometry), are spinel–sapphirine–biotite–gedrite, spinel–corundum–sapphirine–cordierite and orthopyroxene–biotite–cordierite–plagioclase. Högbomite formed by hydrous alteration and oxidation of primary spinel and rutile and/or ilmenite according to the generalised reaction:

Suggested conditions of högbomite formation are 550–620°C and 6–7 kbar. The högbomites contain 10.2–14.7 wt.% MgO, 04).3 wt.% ZnO, 58.9–62.1 wt.% Al2O3 and 15.6-17.6 wt.% Fe as FeO. The two högbomite may belong to different polytypes, as suggested by their differing TiO2 (9.9-10.1 versus 5.7–5.8 wt. %) and calculated Fe3+ – and H2O–contents. The partitioning of Zn between spinel and högbomite is not uniform and is considered to depend upon prevailing fo2 and aH2O.

Kudryavtsevaite, ideally Na3MgFe3+Ti4O12, is a new mineral from kimberlitic rocks of the Orapa area, Botswana. It occurs as rare prismatic crystals, up to 100 μm m across, associated with Mg-rich ilmenite, freudenbergite and ulvöspinel. Kudryavtsevaite is opaque with a vitreous lustre and shows a black streak. It is brittle; the Vickers hardness (VHN100) is 901 kg mm−2 (range: 876–925) (Mohs hardness ∼6). In reflected light, kudryavtsevaite is moderately bireflectant and very weakly pleochroic from dark grey to a slightly bluish grey. Under crossed polars, it is very weakly anisotropic with greyish-bluish rotation tints. Internal reflections are absent. Reflectance values (%), Rmin and Rmax, are: 21.3, 25.4 (471.1 nm), 20.6, 24.1 (548.3 nm), 20.0, 23.5 (586.6 nm) and 19.1, 22.4 (652.3 nm).

Kudryavtsevaite is orthorhombic, space group Pnma, with a = 27.714(1), b = 2.9881(3), c = 11.3564(6) Å, V = 940.5(1) Å3, and Z = 4. The crystal structure [R1 = 0.0168 for 819 reflections with I > 2σ(I)] consists of edge-sharing and corner-sharing chains composed of Mg, Fe3+ and Ti atoms coordinated by six atoms of oxygen and running along the b axis, with Na filling the tunnels formed by the chains. The eight strongest powder-diffraction lines [d in Å (I/I0) (hkl)] are: 7.17 (100) (301), 4.84 (70) (302), 2.973 (35) (901), 2.841 (50) (004), 2.706 (50) (902), 2.541 (50) (312), 2.450 (70) (611), and 2.296 (45) (612). The average results of 12 electron microprobe analyses gave (wt.%): Na2O 16.46(15), CaO 1.01(3), MgO 5.31(5), Fe2O3 22.24(32), Cr2O3 1.05(6), Al2O3 0.03(2), TiO2 53.81(50), total 99.91, corresponding to the empirical formula (Na2.89Ca0.10)Σ2.99(Ti3.67Fe1.523+Mg0.72Cr0.08)Σ5.99O12, or ideally Na3MgFe3+Ti4O12.

The new mineral has been approved by the IMA-CNMNC and named for Galina Kudryavtseva (1947–2006), a well known Russian mineralogist and founder of the Diamond Mineralogy Laboratory and scientific school for investigation of diamond mineralogy and geochemistry at the Lomonosov State University in Moscow, Russia.

The nature of nanocrystalline inclusions and dopant distribution in bismuth-doped silicate fibers and preforms are studied by scanning and transmission electron microscopy, and energy and wavelength-dispersive X-ray microanalysis. The core compositions are Bi:SiO2, Bi:Al2O3–SiO2, Bi:GeO2–SiO2, Bi:Al2O3–GeO2–SiO2, and Bi:P2O5–Al2O3–GeO2–SiO2. Nanocrystals of metallic Bi, Bi2O3, SiO2, GeO2, and Bi4(GeO4)3 are observed in these glasses. These inclusions can be the reason for the background optical loss in bismuth-doped optical fibers. The bismuth concentration of 0.0048±0.0006 at% is directly measured in aluminosilicate optical fibers with effective laser generation (slope efficiency of 27% at room temperature).

Botallackite, Cu2(OH)3Cl, from the Botallack mining area in Cornwall, United Kingdom, has been reinvestigated regarding physical, optical, chemical, and X-ray powder diffraction data. It forms emerald-green tabular crystals slightly elongated along [010] with {001} (dominant), {100}, {010}, and {011}. Botallackite is biaxial positive, 2V=70(2)°, the optical orientation is Y∧c 22(2)° (in obtuse β), Z=b. Electron-microprobe analyses gave CuO 73.26, ZnO 0.22, Cl 16.80, H2O (calc) 12.37, total 102.65, less O=Cl 3.79, total 98.86 wt %, corresponding to the empirical formula Cu1.99Zn0.01(OH)2.97Cl1.03 (based on four anions). Unit cell parameters refined from X-ray powder diffraction data are a 5.7155(5), b 6.1255(6), c 5.6336(4) Å, β 93.090(8), V 196.95(2)Å3,Z=2.

The early days of the electron microprobe were characterized by the variety of designs emerging from different laboratories in Europe, the United States, and the USSR. Examples from Europe illustrate well the diverging trends in the evolutionary process at that time. Later, commercial pressures and a better understanding of user needs forced a rationalization on both sides of the Atlantic, to the point where only few variants have survived. These were memorable days, with scope for healthy rivalry and vigorous debate.

To analyze the elemental composition and topology of the extracellular compartments of the compound eye, the eyes of blowflies Calliphora vicina were rapidly frozen and ultrathin cryosections were freeze dried. Three zones of an ommatidium, peripheral cytosol of visual cells, rhabdomeres, and ommatidial cavities were analyzed by X-ray microprobe analysis. The ommatidial cavity was found to contain sodium and potassium in proportion similar to that in the blowfly hemolymph. Potassium-to-sodium ratio in a cytosol was typical for a cytosol. The rhabdomeres displayed an electrolyte content intermediate between the above compartments. Three topologically connected extracellular compartments were characterized by the experiments with tracers, monastral blue and lanthanum: (1) common intercellular space of ommatidia including peripheral clefts between the visual cells, both tracers entered this compartment; (2) the ommatidial cavity, which is not accessible for monastral blue, however, as revealed by our X-ray microanalysis, it was reachable for lanthanum; (3) rhabdomeric loops, which were accessible for lanthanum entering either via the cavity or from the common intercellular clefts. The above characteristics of the ionic content and topology of ommatidial compartments might suggest higher sodium and lower potassium content in the microvilli as compared with the cytosol. The rhabdomeric and “cavital” plasma membranes are assumed to be permeable for these ions so that a voltage of only 25–30 mV, negative inside, is probably formed across them, much lower than the known resting potential −60 mV across the peripheral plasma membrane of a visual cell.