https://ogma.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 Hydroclimatic variability in Southeast Asia over the past two millennia https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47773 Wed 22 Mar 2023 18:06:21 AEDT ]]> A guide to synchrotron hard X-ray fluorescence mapping of annually laminated stalagmites: Sample preparation, analysis and evaluation https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:49225 20 Megapixels) hardly feasible. For concentrations above 20 ppm the fast mapping (dwell time < 5 ms) through S-μXRF is by far the best methodology to visualise chemical annual cycles in stalagmites.]]> Sun 07 May 2023 09:44:11 AEST ]]> Crystallization pathways, fabrics and the capture of climate proxies in speleothems: examples from the tropics https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:50776 Mon 22 Apr 2024 11:47:11 AEST ]]> The Properties of Annually Laminated Stalagmites-A Global Synthesis https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:46284 Mon 14 Nov 2022 15:48:51 AEDT ]]> High spatial resolution investigation of nucleation, growth and early diagenesis in speleothems as exemplar for sedimentary carbonates https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47225 Fri 16 Dec 2022 10:37:32 AEDT ]]> Formation of calcite in the presence of dissolved organic matter: partitioning, fabrics and fluorescence https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:39968 3) crystals from weak solutions of (NH4)2CO3, CaCl2 and NH4Cl. These solutions also contained peat DOM (from 0 to 15 mgC/L). Fluorescence 3D excitation-emission matrix (3D EEM) analysis showed a strong, positive correlation between [DOM] in the parent-solution, and [DOM] in the calcite. Calcite precipitation was reduced at high DOM concentrations, potentially indicating inhibition of crystallisation. Partition coefficient values showed that DOMaq was subtly preferentially incorporated into calcite. Scanning electron microscope images indicated that the crystal structures were heavily influenced by DOM adsorption with finer, smooth-faced, rhombohedral crystals forming in growth solutions with low aqueous [DOM] (0–5 mgC/L), and prismatic, ‘impure’ crystals produced at high aqueous [DOM] (10 and 15 mgC/L). Overall, our results indicate that authigenic carbonates are likely to faithfully record variations in aqueous [DOM] within the natural range of DOM concentrations in representative freshwater systems (caves, soil water), and that crystal habits are altered by aqueous [DOM] within their growth solutions. We also applied our findings to three flowstones collected from three New Zealand caves which vary in climatic, vegetation and hydrological regimes. We conclude that differences in initial aqueous [DOM] do indeed control incorporation of DOM into calcite, and thus 3D EEM fluorescence can be used to reconstruct original aqueous [DOM] from authigenic carbonates.]]> Fri 15 Jul 2022 10:18:17 AEST ]]>