Phosphorus speciation in calcite speleothems determined from solid-state NMR spectroscopy

摘要: Abstract Variations in speleothem P concentration show cyclic patterns that have important implications for high resolution palaeoclimate and palaeoenvironmental reconstructions. However, little is known about the speciation of calcite speleothems. Here we employ solid-state 31P 1H magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopic techniques as a non-destructive method analyzing distribution The MAS NMR results three peaks indicating presence primary types phosphate species samples from Grotta di Ernesto (northeastern Italy): broad peak at chemical shift δP-31 = 3.1 to 3.7 ppm individual ions incorporated within calcite, narrow set near δP-31 = − 0.9 ppm crystalline monetite δP-31 = 2.9 ppm an unidentified phase. Essentially identical were obtained synthetic calcite/phosphate coprecipitate. Spectra collected sample Grotte de Clamouse (southern France) only 3.5 ppm suggesting possible limit incorporation into structure. These data suggest this system can interact form calcium surface precipitates during infiltration events are subsequently enclosed growth.