Rapid measurement of strontium in speleothems using core-scanning micro X-ray fluorescence

Scroxton, Nick; Burns, Stephen J.; Dawson, P. H.; Rhodes, J. M.; Brent, L.; McGee, David; Heijnis, Hendrik; Gadd, Patricia; Hantoro, Wahyoe S.; Gagan, Mike

doi:10.1016/j.chemgeo.2018.04.008

Cited by 18 publications

(10 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Sr/Ca ratios can be rapidly obtained by non-destructive XRF scanning (Scroxton et al, 2018). For this study, Sr/Ca ratios were measured on an ITRAX XRF core scanner from Cox Analytical Systems (Gothenburg, Sweden) using a 3 kW molybdenum (Mo) X-ray tube.…”

Section: Trace Elementsmentioning

confidence: 99%

Multi-proxy speleothem-based reconstruction of mid-MIS 3 climate in South Africa

Maccali

Meckler

Lauritzen

et al. 2023

Preprint

View full text Add to dashboard Cite

Abstract. The southern coast of South Africa displays a highly dynamical climate as it is at the convergence of both the Atlantic and Indian Ocean, and it is located near the subtropical/temperate zone boundary with seasonal influence of easterlies/westerlies. The region hosts some key archeological sites with records of significant cognitive, technological and social developments. Reconstructions of the state and variability of past climate and environmental conditions around sites of archeological significance can provide crucial context for understanding the evolution of early humans. Here we present a short but high-resolution record of hydroclimate and temperature in South Africa. Our reconstructions are based on trace elements, calcite and fluid inclusion stable isotopes, and fluid inclusion microthermometry from a speleothem collected in Bloukrantz Cave, in the De Hoop Nature Reserve in the Western Cape region of South Africa. Our record covers the time period from 48.3 to 45.2 ka during Marine Isotope Stage 3. Both 𝛿18Oc and 𝛿 13Cc show strong variability and covary with Sr/Ca. This correlation suggests that the control on these proxies originates from internal cave processes such as Prior Calcite Precipitation, which we infer to be related to precipitation amount. The hydroclimate indicators furthermore suggest a shift towards overall drier conditions after 46 ka, coincident with a cooling in Antarctica and drier conditions in the eastern part of South Africa corresponding to the Summer Rainfall Zone. Fluid inclusion-based temperature reconstructions show good agreement between the oxygen isotope and microthermometry methods, and results from the latter display little variation throughout the record, with reconstructed temperatures close to the present-day cave temperature of 17.5 °C. Overall, the BL3 record thus suggests stable temperature from 48.3 to 45.2 ka whereas precipitation was variable with marked drier episodes on sub-millennial timescales.

show abstract

Section: Trace Elementsmentioning

confidence: 99%

Multi-proxy speleothem-based reconstruction of mid-MIS 3 climate in South Africa

Maccali

Meckler

Lauritzen

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…flowstones and stalagmites) (Hill et al, 1997). Inorganic geochemical properties (isotopic and trace element data) (Affolter et al, 2019;Nagra et al, 2017;Scroxton et al, 2018;Williams et al, 1999) and physical properties (e.g. nano-crystal aggregation, open vs. compact columnar fabrics, defect-ridden fabrics) of natural calcium carbonate minerals have been routinely used to determine environmental parameters atof their time of formation (Frisia et al, 2000;Nielsen et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Formation of calcite in the presence of dissolved organic matter: Partitioning, fabrics and fluorescence

et al. 2020

View full text Add to dashboard Cite

Dissolved organic matter (DOM) is omnipresent in natural waters and is commonly incorporated into carbonates. Records of DOM from speleothems (secondary carbonates found in caves) have often been interpreted to reflect groundwater DOM concentrations.However, the fidelity of these records is largely untested. An understanding of the relationship between dripwater and speleothem DOM is thus required to allow speleothems to be reliably used as archives of DOM concentration.We precipitated calcite (CaCO3) crystals from weak solutions of (NH4)2CO3, CaCl2 and NH4Cl. These solutions also contained peat DOM (from 0 to 15 mgC/Lppm). Fluorescence 3D excitation-emission matrix (3D EEM) analysis showed a strong, positive correlation between [DOM] in the parent-solutionaq, and [DOM]calcite 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]aq (0-5 mgC/Lppm), and prismatic, 'impure' crystals produced at high aqueous [DOM]aq (10 and 15 mgC/Lppm). Overall, our results indicate that authigenic carbonates are likely to faithfully record variations in aqueous [DOM]aq within the natural range of DOM concentrations in representative freshwater systems (caves, soil water), and that crystal habits are altered by aqueous [DOM]aq 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]aq do indeed control incorporation of DOM into calcite, and thus 3D EEM fluorescence can be used to reconstruct original aqueous [DOM]aq from authigenic carbonates.

show abstract

“…Although the stalagmites are mainly made of calcium carbonate, seven elements can be detected by CXRF method for stalagmite C9, including Si, K, Fe, Cu, Ni, Sc and Sr. This is because, except for K (~3.31 keV), the characteristic peaks of Si (~1.74 keV), Sc (~4.09 keV), Fe (~6.4 keV), Cu (~8.04 keV), Ni (~7.47 keV) and Sr (~14.2 keV) are far away from the interference of Ca (~3.7 keV) and diffraction peaks (Richter et al, 2006;Scroxton et al, 2018). The spectral peaks produced by Ca and the pseudo-peaks produced by the diffraction of carbonate crystalline matrix do not interfere with identifying characteristic peaks of these elements.…”

Section: Accepted Articlementioning

confidence: 99%

Application of XRF Scanning to Different Geological Archives

Guo

Clemens

Liu

et al. 2021

Earth and Space Science

View full text Add to dashboard Cite

High-resolution XRF scanning is widely used on marine and lake sediment cores as a means of rapidly acquiring elemental concentrations from closely spaced intervals with no damage to the samples. Therefore, guidance on how to obtain reliable datasets and select suitable step sizes for different geological media are of great importance. Here we apply this efficient analytical method to loess, stalagmite, and tridacna samples. The results show that 11 elements (Al,

show abstract

Rapid measurement of strontium in speleothems using core-scanning micro X-ray fluorescence

Cited by 18 publications

References 61 publications

Multi-proxy speleothem-based reconstruction of mid-MIS 3 climate in South Africa

Multi-proxy speleothem-based reconstruction of mid-MIS 3 climate in South Africa

Formation of calcite in the presence of dissolved organic matter: Partitioning, fabrics and fluorescence

Application of XRF Scanning to Different Geological Archives

Contact Info

Product

Resources

About