Environmental context Speleothem chemical records are used to reconstruct environmental change on a broad range of timescales. However, one of the biggest challenges is to link the records contained within speleothems at the sub-annual timescale to changing meteorological conditions. Seasonal infiltration patterns and cave ventilation dynamics are reconstructed through high resolution analysis of speleothem trace element content by synchrotron radiation, building towards proxy records of hydrological variability and winter duration as indices of recent climatic change beyond the instrumental period. Abstract Synchrotron micro-X-ray fluorescence (µXRF) spectrometry is used to reveal trace element patterns within speleothem calcite at the sub-annual scale and provide one of the first calibrations to prevailing meteorological conditions. Mapping of Zn and SO42– within speleothem calcite was performed at the European Synchrotron Radiation Facility over three annual cycles (1977–1979). Peaks in µXRF Zn concentrations occur on an annual basis, although banding of lower XRF intensity reveals multiple events at the sub-annual scale. The delivery of Zn to the speleothem was found to be dependent upon the presence of a water excess, the condition of any overlying snowpack and the pH of the soil solution as controlled by microbial activity. This generated a pattern of Zn event laminae that documented increasing concentrations from winter through to the following autumn and complies with existing models inferring surface-active trace metals are delivered to the point of speleothem growth in association with natural organic matter (referred to as NOM–metal complexes). Minimum and maximum concentrations of speleothem SO42– coincide with winter and summer respectively, in contrast to the near constant SO42– concentrations of the drip water. Fluctuations in speleothem SO42– levels closely follow changes in cave external temperatures, thereby validating existing models of sulfate incorporation into carbonate minerals thought to be driven by cave ventilation dynamics and internal cave atmospheric pCO2 (partial pressure). At the current resolution of analysis, this represents some of the first evidence linking event-based meteorological (temperature and precipitation) records to the trace element content of speleothem calcite, building towards reconstruction of indices of climatic change beyond the instrumental period.
Bound trace element content of bovine retinal disk membranes as determined by particle-induced x-ray emission