Andrzej Kuczumow

Annual resolution analysis of a SW-France stalagmite by X-ray synchrotron microprobe analysis

Abstract A sample of stalagmite from Grotte de Villars, Dordogne, France was analyzed by the use of X-ray synchrotron microprobe in LURE, Orsay, France. Together with the signal of Ca, the main element, much weaker but clear signals of Sr, Fe, Zn and Pb were registered. The X-ray scattered radiation was applied for recognition of the annual zones in the stalagmite structure in parallel with the gray scale morphology from the optical microscope. The elemental scans were superimposed on the optical image of the sample. It was established that places corresponding to dark locations on the annual rings were narrower, composed of less porous matter and had much greater contents of iron and zinc and elevated ratio of Sr/Ca. In the supplementary electron microprobe measurements, the elevated amounts of lighter elements, Si and Mg were found in the same locations. These results will allow a very accurate study of stalagmite elemental composition which is of first importance for paleoclimatic studies from speleothems.

Investigation of petrified wood by synchrotron X-ray fluorescence and diffraction methods

Abstract Pieces of petrified wood from south-eastern Poland comprising one of the greatest European collections were investigated. The age of Miocene wood was estimated at 50 million years. Taxodioxylon sequoianum Gothan. was recognised as the dominating species among the preserved samples. Silica material, basic for the petrifaction processes, was investigated by synchrotron-based microfluorescence and microdiffraction. Different distribution patterns were determined after careful examination of linear scans and elemental maps: calcium, potassium and titanium were uniformly spread in the silica matrix while the iron content was concentrated in clear inclusions; other detected elements, as Cu, Zn, Cr, As were observed mainly in the form of inclusions. There was no difference in microdiffractograms for silica between the places of original dark and light wood. One could find little difference in diffraction patterns of samples with the elevated content of iron. In general, the diffraction patterns of silica from petrified wood could be associated with quartz patterns from 1998 JCPDS-International Centre for Diffraction Data.

Studies on the wood tissue substitution by silica and calcite during the preservation of fossil wood

Abstract Three representative samples of petrified wood were investigated: wood from King George Island, Antarctica; wood from Bio-Bio province, middle Chile and wood from Łukow, Poland. Microdiffraction measurements of the Chilean and Łukow wood were made at LURE. Chilean and Antarctic samples were permineralised by silica material, but the share of undefined calcium silicates in construction of some intracellular locations in the latter sample was significant. In contrast, the wood from Łukow was replaced by calcite with a small presence of secondary silica. Linear scans were conducted using the X-ray microfluorescence beamlines in synchrotron devices in Orsay, France and Pohang, South Korea. The results were completed by the measurements of light elements with the use of electron microprobe. The list of major and minor constituents of all samples was established. The occurrence of such medium-Z elements as Fe, Zn, Cu and Ni was common in the samples. The samples of Chilean wood were more enriched in trace elements and minor amounts of As, La, Br and Cl were found in addition to the previously mentioned elements. Correlation of the trace element contents with the ring structure of the wood was detected. The annual ring, tissue and even cell details of the original wood were preserved by silica and calcite minerals and could be studied using the elemental mapping technique. Implications of the recent study for the material science are indicated.

Analysis of speleothems by electron and X-ray microprobes

A piece of stalagmite from a cave in Winthertore, Belgium, was analysed by the use of capillary tabletop and synchrotron versions of X-ray microprobes and then by the electron microprobe. The potential of these microprobes was tested for the first time in the study of such specific periodic objects. Indirect measurements of the morphology/density of samples were made by the use of Compton and Rayleigh scattered radiation in the X-ray tabletop microprobe and a selected channel in white scattered radiation in the X-ray synchrotron microprobe. In the electron microprobe, the linear profile extracted from the grey-scale transformation of the secondary electron image was used for the same purpose. The elemental analyses were superimposed on the density characteristics of the samples. The inclusions of iron and silicon, measurements of the magnesium/calcium/strontium/barium ratio, profiles of anionic species and the noticeable presence of iodine were among the most important findings. Some of the measured parameters probably allow the creation of thermometric scales for the potential estimation of the climatic conditions during the deposition of the calcite material.

Investigation of chemical composition of belemnite rostra by synchrotron-based X-ray microfluorescence and diffraction and electron microprobe

Abstract Rostra (bullet-shaped internal shells) of two species of belemnites: Belemnopsis sp. (from Bathonian Stage sediments ∼161–166 Ma ago) and Hibolites sp. (from Middle Oxfordian sediments ∼154–157 Ma) were investigated by the use of 1B2 microfluorescence beamline in Pohang Light Source in Korea. The cross-sections of the rostra showed an ordered structure of concentric growth laminae cut across by radial calcite crystals. The inner and outer parts of the cross-section differ in the size of calcite crystals, building the block. Very fine crystals existing in the inner parts of rostra are replaced by monocrystals in their external parts. Some compounds of metallic elements such as iron and zinc are present in the calcite matrices of belemnites. Their presence is especially pronounced in the zones separating particular growth rings. The concentrations of elements in calcite matrix were calibrated by atomic absorption method and the results for alkaline elements are: for Sr ∼1000 ppm for Oxfordian specimen and ∼3000 ppm for Bathonian; for Na, ∼2000 and ∼1400 ppm; for K, ∼160 and ∼100 ppm, respectively. The synchrotron-based investigations were complemented with the electron microprobe search for low-Z elements; using this method sodium, potassium, aluminum, silicon, chlorine and sulfur were detected in the matrix. The variability of molar Mg/Ca ratio follows the optical variability of the annual growth zones of the samples, suggesting that this ratio could be used as a palaeothermometer. Possibilities of both application of the elemental data for the estimation of palaeotemperatures, and cross-checking with the isotopic data are discussed. The substantial amounts of the excess carbon were detected in the samples. They are concluded to be potentially useful for the analysis of remnants of original biological matter.

Analysis of the distribution of inorganic components of wood by x-ray capillary microprobe

An x-ray microprobe was used to perform both linear and area scans of wood material from Polish Pinus silvestris. The investigation revealed variations in behaviour and distribution for different chemical elements. Univalent cations and anions generally show a very irregular distribution in wood which is difficult to associate with any known structural factors. The multivalent element distribution as a rule follows the ring density pattern. Some elements (e.g. iron) show a clear tendency to be included in channel-like structures.

Structural investigations of a series of petrified woods of different origin

Abstract Since the investigations on petrified wood performed so far have not proved the assumption that the ring structure is coupled to the changes in the crystalline form of silica, attention was paid to other possible reasons. Using small angle X-ray scattering methods we determined the Porod curves and pore size distributions for five different samples of petrified wood, of different origin. We observed clear porosity differences in different samples. In addition, the normal X-ray diffractometric measurements were carried out, which gave a totally uniform image of the crystallographic structure of all the samples. All of them were made of pure α-quartz. The differentiation of rings in dark and bright zones should be put down to the changes in porosity rather than to other factors. The pores seem to be much more concentrated in those ring locations, which correspond to the original dark wood positions in living wood.

Microprobe investigations of patterned natural and petrified biological objects

The possibilities of examining patterned natural and mineralised biological objects, using X-ray synchrotron facilities, complemented by electron microprobe and optical analysis are reviewed. The objects under investigation include: petrified wood, speleothems, corals, shells of molluscs and remains of belemnites. All those objects have important information embedded in their patterned structure. Using microprobe type devices, one can disentangle the internal structure of the objects and reveal the hidden information. This information can be of great significance to climatic, geological, chronological, and ecological studies and specific examples in each category are shown, taken from our work and compared with the results of other authors where necessary. The added value of the X-ray and electron microprobe measurements in relation to the mass-spectrometric methods is shown for the specific cases. In addition, the results concern materials where organic and even biological material is combined with inorganic matter, like calcite, silica varieties and metal oxides. The investigation of such patterned objects as goethitized wood, composed of goethite, calcite and organic matter should therefore be of interest to materials scientists, synthesizing composite materials.

Novel theoretical analyses of some features of X-ray spectrometry—III: Concentration correction equations derived for scattered radiation

Abstract Since, in previous work, it was possible to derive the concentration correction equations from the fundamental parameter equations for the fluorescent X-ray radiation, a similar trial was performed for the coherently and Compton scattered radiations. The derived equations can be named “concentration correction equations for scattered radiation”. Their form is more complicated than their fluorescent analogues.

Investigations of different trajectories of X-rays in capillaries

Using the methods of geometrical optics, different cases for allowed X-ray trajectories in single capillaries are studied and it is proved that they cannot be described by the same sets of equations. Three main cases should be considered. In two cases, the test X-rays strike both sides of the capillary upon passing, be the second wall convex or concave. In the third case, called the whispering gallery mode, the path is allowed along the single, external wall of the capillary. This case is realistic for some off-axis, close to the wall, trajectories. A trajectory along the capillary with the curved main axis is the particular case, joining the features of the cases mentioned earlier. The separate consideration of different kinds of trajectories has important implications. The first case corresponds to the ideal trajectory in single capillaries, whereas the second and third describe realistic trajectories in the compound polycapillary systems. The transformation of the polycapillary systems into the coaxial polycylindrical systems is considered. In the third case, which constitutes a transition to trajectories of X-rays on the curved mirror surfaces, the removal of the opposite wall of the capillary can be allowed. Surprisingly, very simple angular relationships lead to the differential equations, describing capillary optics in the terms of geometrical parameters of capillary. The equations describing the surfaces on which the X-rays behave in isoreflective way, i.e. they have the same angle of incidence all along the trajectory, are derived. The proposed approach is widened for modeling of surfaces in order to enable the reflections with continuously changing and controlled reflection angle.