Ombrotrophic peatlands are remarkable repositories of high-quality climatic signals because their only source of nutrients is precipitation. Although several analytical techniques are available for analysing inorganic components in peat samples, they generally provide only low-resolution data sets. Here we present a new analytical approach for producing high-resolution data on main and trace elements from ombrotrophic peat cores. Analyses were carried out on a 7-m-long peat core collected from Danta di Cadore, North-Eastern Italy (46° 34′ 16″ N, 12° 29′ 58″ E). Ca, Ti, Cr, Fe, Cu, Zn, Ga, Sr, Y, Cd, Ba and Pb were detected at a resolution of 2.5 mm with a non-destructive X-ray fluorescence core scanner (XRF-CS). Calibration and quantification of the XRF-CS intensities was obtained using collision reaction cell inductively coupled plasma quadruple mass spectrometry (CRC-ICP-QMS). CRC-ICP-QMS measurements were carried out on discrete samples at a resolution of 1 cm, after dissolution of 150-mg aliquots with 9 ml HNO3 and 1 ml HF at 220 °C in a microwave system. We compare qualitative XRF-CS and quantitative CRC-ICP-MS data and, however the several sources of variability of the data, develop a robust statistical approach to determine the R2 and the coefficient of a simple regression model together with confidence intervals. Perfect positive correlations were estimated for Cd, Cr, Pb, Sr, Ti and Zn; high positive correlations for Ba (0.8954), Y (0.7378), Fe (0.7349) and Cu (0.7028); while moderate positive correlations for Ga (0.5951) and Ca (0.5435). With our results, we demonstrate that XRF scanning techniques can be used, together with other well-established geochemical techniques (such as ICP-MS), to produce high-resolution (up to 2.5 mm) quantitative data from ombrotrophic peat bog cores.
ICP-MS XRF Trace elements Palaeoclimate
This is a preview of subscription content, log in to check access.
The research leading to these results has received funding from CNR-IDPA (Next-Data project), Fondazione per l’Alta Cultura Bellunese and the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant agreement no. 267696—‘EARLYhumanIMPACT’. This is EARLYhumanIMPACT contribution 12. We are grateful to colleagues for technical and scientific assistance, and in particular, we would like to thank David Hodell for allowing the author Luisa Poto access to the facilities at the Godwin Laboratory for Palaeoclimate Research in the Department of Earth Sciences (Cambridge University) and Michael Krachler for his valuable advice on the acid digestion of peat samples.
Shotyk W (1996) Peat bog archives of atmospheric metal deposition: geochemical evaluation of peat profiles, natural variations in metal concentrations, and metal enrichment factors. Environ Rev 4:149–183CrossRefGoogle Scholar
Weiss D, Shotyk W, Kramers JD, Gloor M (1999) Sphagnum mosses as archives of recent and past atmospheric lead deposition in Switzerland. Atmos Environ 33:3751–3763CrossRefGoogle Scholar
Shotyk W, Krachler M, Martinez-Cortizas A et al (2002) A peat bog record of natural, pre-anthropogenic enrichments of trace elements in atmospheric aerosols since 12 370 14C yr BP, and their variation with Holocene climate change. Earth Planet Sci Lett 199:21–37CrossRefGoogle Scholar
De la Rosa G, Peralta-Videa JR, Gardea-Torresdey JL (2003) Utilization of ICP/OES for the determination of trace metal binding to different humic fractions. J Hazard Mater 97:207–218CrossRefGoogle Scholar
Chambers FM, Booth RK, De Vleeschouwer F et al (2012) Development and refinement of proxy-climate indicators from peats. Quat Int 268:21–33CrossRefGoogle Scholar
Krachler M (2007) Environmental applications of single collector high resolution ICP-MS. J Environ Monit 9:790–804CrossRefGoogle Scholar
Yafa C, Farmer JG, Graham MC et al (2004) Development of an ombrotrophic peat bog (low ash) reference material for the determination of elemental concentrations. J Environ Monit 6:493–501CrossRefGoogle Scholar
Mighall TM, Timberlake S, Foster IDL et al (2009) Ancient copper and lead pollution records from a raised bog complex in Central Wales, UK. J Archaeol Sci 36:1504–1515CrossRefGoogle Scholar
Rausch N, Nieminen T, Ukonmaanaho L et al (2005) Comparison of atmospheric deposition of copper, nickel, cobalt, zinc, and cadmium recorded by Finnish peat cores with monitoring data and emission records. Environ Sci Technol 39(16):5989–5998CrossRefGoogle Scholar
De Vleeschouwer F, van Vliët-Lanoé B, Fagel N et al (2008) Development and application of high-resolution petrography on resin-impregnated Holocene peat columns to detect and analyse tephras, cryptotephras, and other materials. Quat Int 178:54–67CrossRefGoogle Scholar
Krachler M, Mohl C, Emons H, Shotyk W (2002) Influence of digestion procedures on the determination of rare earth elements in peat and plant samples by USN-ICP-MS. J Anal At Spectrom 17:844–851CrossRefGoogle Scholar
Krachler M, Shotyk W (2004) Natural and anthropogenic enrichments of molybdenum, thorium, and uranium in a complete peat bog profile, Jura Mountains, Switzerland. J Environ Monit 6:418–426CrossRefGoogle Scholar
Krachler M, Mohl C, Emons H, Shotyk W (2003) Two thousand years of atmospheric rare earth element (REE) deposition as revealed by an ombrotrophic peat bog profile, Jura Mountains, Switzerland. J Environ Monit 5:111–121CrossRefGoogle Scholar
Tanner SD, Baranov VI, Bandura DR (2002) Reaction cells and collision cells for ICP-MS: a tutorial review. Spectrochim Acta B At Spectrosc 57:1361–1452CrossRefGoogle Scholar
Givelet N, Le Roux G, Cheburkin A et al (2004) Suggested protocol for collecting, handling and preparing peat cores and peat samples for physical, chemical, mineralogical and isotopic analyses. J Environ Monit 6:481–492CrossRefGoogle Scholar
Weltje GJ, Tjallingii R (2008) Calibration of XRF core scanners for quantitative geochemical logging of sediment cores: theory and application. Earth Planet Sci Lett 274:423–438CrossRefGoogle Scholar
Richter TO, van der Gaast S, Koster B et al (2006) The Avaatech XRF Core Scanner: technical description and applications to NE Atlantic sediments. Geol Soc Lond Spec Publ 267:39–50CrossRefGoogle Scholar
Tjallingii R, Roehl U, Koelling M, Bickert T (2007) Influence of the water content on X-ray fluorescence core-scanning measurements in soft marine sediments. Geochem Geophys Geosyst 8(2):12Google Scholar
Poto L, Gabrieli J, Crowhurst SJ et al (2013) The first continuous Late Glacial - Holocene peat bog multi-proxy record from the Dolomites (NE Italian Alps). Quat Int 306(3):71–79CrossRefGoogle Scholar
Gabrieli J, Carturan L, Gabrielli P et al (2011) Impact of Po Valley emissions on the highest glacier of the Eastern European Alps. Atmos Chem Phys 11:8087–8102CrossRefGoogle Scholar