CP Climate of the Past CP 1814-9332 Copernicus GmbH Göttingen, Germany 10.5194/cp-8-2039-2012 A re-evaluation of the palaeoclimatic significance of phosphorus variability in speleothems revealed by high-resolution synchrotron micro XRF mapping Frisia S. 1 Borsato A. 1 Drysdale R. N. 2 Paul B. 3 4 Greig A. 3 Cotte M. 5 School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308 NSW, Australia Department of Resource Management and Geography, The University of Melbourne, Parkville 3010 Victoria, Australia School of Earth Sciences, The University of Melbourne, 3010 Australia CODES ARC Centre of Excellence in Ore Deposits and School of Earth Sciences, University of Tasmania, Australia European Synchrotron Radiation Facility, 38043, Grenoble Cedex, France 14 12 2012 8 6 2039 2051 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.clim-past.net/8/2039/2012/cp-8-2039-2012.html The full text article is available as a PDF file from http://www.clim-past.net/8/2039/2012/cp-8-2039-2012.pdf

Phosphorus (P) is potentially a very important environmental proxy in speleothem palaeoclimate reconstructions. However, the transfer of P to a speleothem seems to vary between cave sites. Therefore, it is important to investigate the source of P and the way it is incorporated into a speleothem on a site-by-site basis before it can be used as a robust palaeoclimate proxy. <br><br> In this paper, the distribution of P in one modern and two Early Pliocene speleothems formed in coastal caves on Christmas Island (Indian Ocean) and the Nullarbor Plain (southern Australia) is investigated using microscopy and ultra-high resolution chemical mapping. <br><br> Phosphorus has been found to be both incorporated in the lattice and present as diverse P-rich phases. Monitoring data from Christmas Island suggest that co-precipitation of P-rich phases occurs when "prior calcite precipitation" decreases following recharge, even if the drip rate decreases. Microbial mediation may also play a role, which complicates a direct climate relationship between P and hydrology. We find that some P-enriched layers contain dissolution features, with possible involvement of microbial mats which colonise pores during reduced drip rates associated with prolonged dry spells. <br><br> In the two Early Pliocene speleothems the relationship between P and microbial laminae is clearer. Both petrographic and chemical data suggest that phosphorus-rich phases in the microbial laminae mark intervals of reduced drip rates, which may indicate dry intervals during the otherwise wet palaeoclimate of the Early Pliocene. <br><br> We develop a <i>speleothem distribution coefficient</i> for phosphorus (SK<sub>P</sub>) rather than the thermodynamic partition coefficient (K<sub>P</sub>) to account for the presence of crystalline phosphate inclusions. SK<sub>P</sub> describes P enrichment in speleothems regardless of the process, as similar mechanisms of phosphate co-precipitation may be in operation in biotic and abiotic conditions. <br><br> The most important implication of our study is that variability in P concentration may be related to diverse processes which can be recognized through petrographic observations and chemical mapping. In particular, there may not be a direct relation between an increase in P concentration and seasonal infiltration as has been found in some previous studies, especially if the source of this element is not the labile phosphate released through leaching during seasonal vegetation dieback in temperate climates.

 References Addadi, L., Raz, S., and Weiner, S.: Taking advantge of disorder: amorphous calcium carbonate and its roles on biomineralization, Adv. Mat., 12, 959–970, 2003. Alonso-Zarza, A. M. and Wright, V. P.: Calcretes, in: Carbonates in Continental Settings, edited by: Alonso-Zarza, A. M. and Tanner, L. H., Developments in Sedimentology, Elsevier, Amsterdam, 269–318, 2010. Ayliffe, L. K., Veeh, H. H., and Chivas, A.: Oxygen isotopes of phosphate and the origin of Island apatite deposits, Earth Planet. Sci. Lett., 108, 119–129, 1992. Banfield, J. F. and Nealson, K. H. (Eds.): Geomicrobiology: Interactions Between Microbes and Minerals, Mineralogical Society of America Reviews in Mineralogy, 35, 448~pp., 1997. Barton, H. A. and Northrup, D. E.: Geomicrobiology in cave environments: past, current and future perspectives, J. Cave Karst Stud., 69, 163–178, 2007. Blyth, A. J. and Frisia, S.: Molecular evidence for bacterial mediation of calcite formation in cold high-altitude caves, Geomicrobiol. J., 25, 101–111, 2008. Borsato, A., Frisia, S., Jones, B., and van der Borg, K.: Calcite moonmilk: crystal morphology and environment of formation in caves in the Italian Alps, J. Sediment. Res., 70, 1179–1190, 2000. Borsato, A., Frisia, S., Fairchild, I. J., Somogyi, A., and Susini, J.: Trace element distribution in annual stalagmite laminae mapped by micrometer-resolution X-ray fluorescence: implications for incorporation of environmentally significant species, Geochim. Cosmochim. Ac., 71, 1494–1512, 2007. Braissant, O., Cailleau, G., Dupraz, C. M., and Verrecchia, E.: Bacterially induced mineralization of calcium carbonate in terrestrial environments: The role of expolysaccharides and amino acids, J. Sediment. Res., 73, 485–490, 2003. Brierley, C. M. and Fedorov, A. V.: Relative importance of meridional and zonal sea surface temperature gradients for the onset of the ice ages and Pliocene-Pleistocene climate evolution, Paleoceanography, 25, 1–16, 2010. Cacchio, P., Contento, R., Ercole, C., Cappuchio, G., Martinez, M. P., and Lepidi, A.: Involvement of microorganisms in the formation of carbonate speleothems in the Cervo Cave (L'Aquila-Italy), Geomicrobiol. J., 21, 497–509, 2004. Cañaveras, J. C., Sanchez-Moral, S., Soler, V., and Saiz-Jimenez, C.: Microbial communities associated with hydromagnesite and needle fiber aragonite deposits in a karstic cave (Altamira, Northern Spain), Geomicrobiol. J., 12, 9–25, 1999. Castanier, S., Le Metayer-Levrel, G., and Perthuisot, J.-P.: Bacterial roles in the precipitation of carbonate minerals, in: Microbial Sediments, edited by: Riding, R. E. and Awramik, S. M., Springer-Verlag, Heidelberg, 32–39, 2000. Combes, C. and Rey, C.: Adsorption of proteins on calcium phosphate materials bioactivity, Biomaterials, 23, 2817–2823, 2002. Dreybrodt, W. and Scholz, D.: Climatic dependence of stable carbon and oxygen isotope signals recorded in speleothems: from soil water to speleothem calcite, Geochim. Cosmochim. Ac., 75, 734–752, 2011. Fairchild, I. J. and Baker, A.: Speleothem Science: From Process to Past Environment, Wiley-Blackwell, 450~pp., 2012. Fairchild, I. J., Baker, A., Borsato, A., Frisia, S., Hinton, R. W., McDermott, F., and Tooth, A. F.: Annual to sub-annual resolution of multiple trace-element trends in speleothems, J. Geol. Soc., 158, 831–841, 2001. Fairchild, I. J., Spötl, C., Frisia, S., Borsato, A., Susini, J., Wynn, P. M., Cauzid, J., and EIMF: Petrology and geochemistry of annually laminated stalagmites from an Alpine cave (Obir, Austria): seasonal cave physiology, in: Tufas and speleothems: unravelling the microbial and physical controls, edited by: Pedley, H. M. and Rogerson, M., Geological Society, London, Special Publications, 336, 295–321, 2010. Filippelli, G. M.: The Global Phosphorous Cycle in: Phosphates – Geochemical, Geobiological and Materials Importance, edited by: Kohn, M. J., Rakovan, J., and Huges, J. M., Mineralogical Society of America Reviews in Mineralogy and Geochemistry, 48, 391–425, 2002. Frisia, S.: Petrographic evidence for diagenesis in speleothems: Some examples, Speleochronos, 7, 21–30, 1996. Frisia, S. and Borsato, A.: Karst, in: Carbonates in Continental Settings, edited by: Alonso-Zarza, A. M. and Tanner, L. H., Developments in Sedimentology, Elsevier, Amsterdam, 269–318, 2010. Frisia, S., Borsato, A., Fairchild, I. J., and McDermott, F.: Calcite fabrics, growth mechanisms, and environments of formation in speleothems from the Italian Alps and South-western Ireland, J. Sediment. Res., 70, 1183–1196, 2000. Frisia, S., Borsato, A., Fairchild, I. J., and Susini, J.: Variations in atmospheric sulphate recorded in stalagmites by synchrotron micro-XRF and XANES analyses, Earth Planet. Sci. Lett., 235, 729–740, 2005. Grimes, K. G.: Karst features of Christmas Island (Indian Ocean), Helictite, 37, 41–58, 2001. Griffiths, M. L., Drysdale, R. N., Gagan, M. K., Frisia, S., Zhao, J.-X., Ayliffe, L. K. Hantoro, W. S., Fischer, M. J., Feng, Y.-X., and Suwargadi, B. W.: Evidence for Holocene changes in Australian-Indonesian monsoon rainfall from stalagmite trace elements and stable isotope ratios, Earth Planet. Sci. Lett., 292, 27–38, 2010. Hartland, H., Fairchild, I. J, Lead, J. R., Borsato, A., Baker, A., Frisia, S., and Baalousha, M.: From soil to cave: Transport of trace metals by natural organic matter in cave dripwaters, Chem. Geol., 304–305, 68–82, 2012. Hendy, C. H.: The isotopic geochemistry of speleothems – I. The calculation of the effects of different modes of formation on the isotopic composition of speleothems and their applicability as paleoclimatic indicators, Geochim. Cosmochim. Ac., 35, 801–824, 1971. Hellstrom, J. C. and McCulloch, M. T.: Multi-proxy constraints on the climatic significance of trace element records from a New Zealand speleothem, Earth Planet. Sci. Lett., 179, 287–297, 2000. House, W. A. and Donaldson, L.: Adsorption and coprecipitation of phosphate in calcite, J. Colloid Interf. Sci., 112, 309–324, 1983. House, W. A., Casey, H., Donaldson, L., and Smith, S.: Factors affecting the coprecipitation of inorganic phosphate with calcite in hardwaters. I – Laboratory Studies, Water Resour., 20, 917–922, 1986. Hu, C., Huang, J., Fang, N., Xie, S., Henderson, G., and Cai, Y.: Adsorbed silica in stalagmite carbonate and its relationship to past rainfall, Geochim. Cosmochim. Ac., 69, 2285–2292, 2005. Hua, Q., McDonald, J., Redwood, D., Drysdale, R., Lee, S, Fallon, S., and Hellstrom, J.: Robust chronological reconstruction for young speleothems using radiocarbon, Quaternary Geochronol., http://dx.doi.org/10.1016/j.quageo.2012.04.017doi:10.1016/j.quageo.2012.04.017, in press, 2012. Huang, Y., Fairchild, I. J., Borsato, A., Frisia, S., Cassidy, N. J., McDermott, F., and Hawkesworth, C. J.: Seasonal variations in Sr, Mg and P in modern speleothems (Grotta di Ernesto, Italy), Chem. Geol., 175, 429–448, 2001. Ishikawa, M. and Ichikuni, M.: Coprecipitation of phosphate with calcite, Chem. J., 15, 283–288, 1981. James, J. M.: Corrosion par melange des eaux dans les grottes de la Plaine de Nullarbor, Australia, in: Karst et Evolutions Climatique, edited by: Salomon, J.-N. and Maire, R., Presses Universitaires de Bordeaux, Bordeaux, 333–348, 1992. Jones, B.: Microbial activity in caves – a geological perspective, Geomicrobiol. J., 18, 1–13, 2001. Jones, B.: Phosphatic precipitates associated with actinomycetes in speleothems from Grand Cayman, British West Indies, Sediment. Geol., 219, 302–317, 2009. Jones, B.: The preferential association of dolomite with microbes in stalactites from Cayman Brac, British West Indies, Sediment. Geol., 226, 94–19, 2010a. Jones, B.: Speleothems in a wave-cut notch, Cayman Brac, British West Indies: the integrated product of subaerial precipitation, dissolution, and microbes, Sediment. Geol., 232, 15–34, 2010b. Kominz, M. A., Miller, K. G., and Browning, J. V.: Long-term and short-term global Cenozoic sea-level estimates, Geology, 26, 311–314, 1998 Lewis, S. C., Gagan, M. K. Ayliffe, L. K., Zhao, J.-X., Hantoro, W. S., Treble, P. C., Hellstrom, J., La Grande, A., Kelley, M., Schmidt, G. A., and Suwargadi, B. W.: High-resolution stalagmite reconstructions of Australian-Indonesian monsoon rainfall variability during Heinrich stadial 3 and Greenland interstadial 4, Earth Planet. Sci. Lett., 303, 133–142, 2011. Mason, H. E., Frisia, S., Tang, Y., Reeder, R. J., and Phillips, B.: Phosphorus speciation in calcite speleothems determined from solid-state NMR spectroscopy, Earth Planet. Sci. Lett., 254, 313–322, 2007. Miller, C. R., James, N. P., and Bone, Y.: Prolonged carbonate diagenesis under an evolving late Cenozoic climate; Nullarbor Plain, southern Australia, Sediment. Geol., 261–262, 33–49, 2012. Miorandi, R., Borsato, A., Frisia, S., Fairchild, I. J., and Richter, D. K.: Epikarst hydrology and implications for stalagmite capture of climate changes at Grotta di Ernesto (NE Italy): results from long-term monitoring, Hydrol. Process., 24, 3101–3114, 2010. Morse, J. W., Gledhill, D. K., and Millero, F. J.: CaCO<sub>3</sub> precipitation kinetics in waters from the Great Bahama Bank: Implications for the relationship between Bank hydrochemistry and whitings precipitation kinetics in waters from the Great Bahama Bank: Implications for the relationship between Bank hydrochemistry and whitings, Geochim. Cosmochim. Ac., 67, \mbox2819–2826, 2003. Nash, D. J. and Ullyott, J. S.: Silcrete, in: Geochemical Sediments and Landscapes, edited by: Nah, D. J. and McLaren, S., Blackwell Publishing, 95–143, 2007. Paton, C., Hellstrom, J., Paul, B., Woodhead, J., and Hergt, J.: Iolite: Freeware for the visualisation and processing of mass spectrometric data, J. Anal. Atom. Spectrom., 26, 2508–2518, 2011. Polyak, V. J. and Güven, N.: Authigenesis of trioctaehedral smectite in magnesium-rich carbonate speleothems in Carlsbad Cavern and other caves of the Guadalupe Mountains, New Mexico, Clay. Clay Miner., 48, 317–321, 2000. Prior, L. D. and Eamus, D.: Seasonal changes in hydraulic conductance, xylem embolism and leaf area in Eucalyptus tetrodonta and Eucalyptus miniata saplings in a north Australian savanna, Plant Cell Environ., 23, 955–965, 2000. Redwood, D. A., Drysdale, R. N., Goodwin, I. D., McDonald, J., Hellstrom, J. C., Hodge, E., and Jeffery, M.: The use of geochemical properties as climate indicators from a Christmas Island (Indian Ocean) stalagmite, Geophys. Res. Abstracts, 9, SRef-ID:1607-7962/gra/EGU2007-A-05921, 2007. Romanek, C. S., Grossmann, E. L., and Morse, J. W.: Carbon isotopic fractionation in synthetic aragonite and calcite: Effects of temperature and precipitation rate, Geochim. Cosmochim. Ac., 56, 419–430, 1992. Rossi, C., Lozano, R. P., Isanta, N., and Hellstrom, J.: Manganese stromatolites in caves: El Soplao (Cantabria, Spain), Geology, 38, 1119–1122, 2010. Sánchez-Román, M., Rivadeneyra, M. A., Vasconcelos, C., and McKenzie, J. A.: Biomineralization of carbonate and phosphate by moderately halophilic bacteria, FEMS Microbiology Ecology, 61, 273–284, 2007. Scholz, D., Mühlinghaus, C., and Mangini, A.: Modelling $\delta ^13$C and $\delta^18$O in the solution layer on stalagmite surfaces, Geochim. Cosmochim. Ac., 73, 2592–2602, 2009. Sø, H. U., Postma, D., Jakobsen, R., and Larsen, F.: Sorption of phosphate onto calcite; results from batch experiments and surface complexation modeling, Geochim. Cosmochim. Ac., 75, 2911–2923, 2011. Steph, S., Tiedemann, R., Prange, M., Groeneveld, J., Schulz, M., Timmermann, A., Nurnberg, D., Ruhlemann, C., Saukel, C., and Haug, G. H.: Early Pliocene increase in thermohaline overturning: A precondition for the development of the northern equatorial Pacific cold tongue, Paleoceanography, 25, 1–17, 2010. Stoll, H. M., Müller, W., and Prieto, M.: I-STAL, a model for interpretation of Mg/Ca, Sr/Ca and Ba/Ca variations in speleothems and its forward and inverse application on seasonal to millennial scales, Geochem. Geophys. Geosys., 13, Q09004, http://dx.doi.org/10.1029/2012GC004183doi:10.1029/2012GC004183, 2012. Treble, P., Shelley, J. M. G., and Chappell, J.: Comparison of high resolution sub-annual records of trace elements in a modern (1911–1992) speleothem with instrumental climate data from southwest Australia, Earth Planet. Sci. Lett., 216, 141–153, 2003. Tremaine, D. M., Froelich, P. N., and Wang, Y.: Speleothem calcite farmed in situ: Modern calibration of $\delta^18$O and $\delta^13$C palaeoclimate proxies in a continuously-monitored natural cave system, Geochim. Cosmochim. Ac., 75, 4929–4950, 2011. Trueman, N. A.: The phosphate, volcanic and carbonate rocks of Christmas Island (Indian Ocean), J. Geol. Soc. Aust., 12, 261–283, 1965 Turin, H. J. and Webb, J. A.: Groundwater geochemistry and isotopes near Mullamullang Cave, Nullarbor Plain, Western Australia, Geological Society of America Annual Meeting, Denver, Colorado, Abstract, 218–23, 2002. Van Leerdam, D. M., Williams, P. A., and Cairney, J. W. G.: Phosphate – solubilising abilities of ericoid mycorrhizal endophytes of Woollsia pungens (Epacridaceae), Australian, J. Botany, 49, 75–80, 2001. Warren, L. A., Maurice, P. A., Parmar, N., and Ferris, F. G.: Microbially Mediated Calcium Carbonate Precipitation: Implications for Interpreting Calcite Precipitation and for Solid-Phase Capture of Inorganic Contaminants, Geomicrobiol. J., 18, 93–115, 2001. Woodhead, J., Hellstrom, J., Maas, R., Drysdale, R., Zanchetta, G., Devine, P., and Taylor, E.: U-Pb geochronology of speleothems by MC-ICPMS, Quaternary Geochronol., 1, 208–221, 2006.