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An in-depth examination of rheology within the deep sections of polar ice sheets is essential for enhancing our understanding of glacial flow. In this study, we investigate the crystalline textural properties of the 3035-m-long Antarctic deep ice core, with a particular emphasis on its lowermost 20 %. We examine the crystal orientation fabric (COF) and compare it with various other properties from the ice core. In the uppermost approximately 80 % thickness zone (UP80 %), the clustering strength of single pole COF steadily increased, reaching its possible maximum at the bottom of the UP80 %. Below 1800 m in the UP80 %, layers with more or fewer dusty impurities exhibit slower or faster growth of cluster strength. This situation continued until 2650 m. In the remaining lowermost approximately 20 % thickness zone (LO20 %), the trend of the COF clustering strength changed around 2650 m and exhibited substantial fluctuations below this depth. In more impurity-rich layers, stronger clustering is maintained. In impurity-poor layers, relaxation of the COF clustering occurred due to the emergence of new crystal grains with c -axis orientation distinctly offset from the existing cluster, and dynamic recrystallization related to this emergence. The less impure layers show apparent features of bulging and migrating grain boundaries. We argue that the substantial deformational regime of polar ice sheets involves dislocation creep in both UP80 % and LO20 %, with dynamic recrystallization playing a critical role in the LO20 %, particularly in impurity-poor layers, to recover a potential of COF available for the continuation of dislocation-creep-based deformation. Furthermore, we observe that layers and cluster axes of COF rotate meridionally due to rigid-body rotation caused by simple shear strain above subglacial slopes. These features provide vital clues for the development of the 3D structure of polar ice sheets in the deeper part, leading to inhomogeneous deformation between layers in various thickness scales, and the formation of folds, faults and mixing depending on the layers. [ABSTRACT FROM AUTHOR]

In recent decades, surface melting on the inland Greenland ice sheet has increased, leading to significant meltwater-refreezing in the snow and firn. Increased knowledge of the physical and chemical characteristics of these melt features (i.e., ice layers) is needed to help estimate future global sea-level rise. Here, using a combination of microscopy and spectroscopy, we investigate the size, shape, location, and chemical compositions of inclusions in 12 ice layers of the SIGMA-A ice core in the northwestern Greenland ice sheet (78°03′06″N, 67°37′42″W, 1490 m a.s.l.). In the ice layers, we found inclusions exceeding 30 μm diameter that could only be formed by melting–refreezing, which we classify into columnar-, particle-, and rod-like inclusions. We propose that the smaller columnar- and particle-like inclusions of solid Na2SO4⋅10H2O and CaSO4⋅2H2O form first, within the ice grains, followed by the larger rod-like inclusions of brines with mainly Na+ and Cl− in grain boundaries. Our results suggest a new proxy that may help identify past warm climates in deeper ice cores in Greenland and for studying future ice sheet melting behavior. [ABSTRACT FROM AUTHOR]

The climate of the past 430 kyr is guided by large-amplitude 100-kyr glacial-interglacial cycles (5). Such cycles are triggered by the Earth's orbital changes and then amplified by various land-atmosphere [...], Sulphate aerosols, particularly micrometre-sized particles of sulphate salt and sulphate-adhered dust, can act as cloud condensation nuclei, leading to increased solar scattering that cools Earth's climate (1,2). Evidence for such a coupling may lie in the sulphate record from polar ice cores, but previous analyses of melted ice-core samples have provided only sulphate ion concentrations, which may be due to sulphuric acid (3). Here we present profiles of sulphate salt and sulphate-adhered dust fluxes over the past 300,000 years from the Dome Fuji ice core in inland Antarctica. Our results show a nearly constant flux of sulphate-adhered dust through glacial and interglacial periods despite the large increases in total dust flux during glacial maxima (4). The sulphate salt flux, however, correlates inversely with temperature, suggesting a climatic coupling between particulate sulphur and temperature. For example, the total sulphate salt flux during the Last Glacial Maximum averages 5.78 mg [m.sup.-2] [yr.sup.-1], which is almost twice the Holocene value. Although it is based on a modern analogue with considerable uncertainties when applied to the ice-core record, this analysis indicates that the glacial-to-interglacial decrease in sulphate would lessen the aerosol indirect effects on cloud lifetime and albedo, leading to an Antarctic warming of 0.1 to 5 kelvin.

We propose a new mode of total reflection X-ray fluorescence (TXRF) analysis called 'Sweeping-TXRF' for the characterization of wafer surface contaminations in semiconductor manufacturing. Essentially, Sweeping-TXRF is the mapping of an entire surface with a very short data acquisition time for each individual spot. Sweeping-TXRF provides three-dimensional views for individual elements on a wafer in a very short period of time, a method that had never before been achieved by traditional methods. Dedicated software for this method was developed and tested, and the results are quite promising for routine contamination characterization. Index Terms--Chemical analysis, mapping, nondestructive analysis, total reflection X-ray fluorescence (TXRF).

Total-reflection X-ray fluorescence (TXRF) spectrometry with no chemical preconcentration, often called 'straight-TXRF', is now widely used in the semiconductor industry. The small detection area of TXRF enables mapping measurement of contamination of the semiconductor surface, which is very useful in process characterization. However, the small detection area had been believed to limit rapid whole-surface analysis. Contrary to this general understanding, in this study we demonstrated that a new method, called 'sweeping-TXRF', which is essentially short-time multipoint mapping by straight-TXRF, can rapidly provide an average concentration. A considerable problem of this method is the contribution of errors in glancing angle and areal element distribution to the fluorescence. Using statistics, we examined the errors and demonstrated that most of them are canceled and are not significant in actual semiconductor applications. The results of an experiment that measured localized 6 x [10.sup.10] atoms [cm.sup.-2] nickel contamination supported the above conclusion. Applying sweeping-TXRF to existing TXRF instruments is easy-the only requirement is a small software modification. We believe that sweeping-TXRF will be utilized for rapid whole-surface analysis in many fields, especially in the semiconductor industry.