Speleothem luminescence

Baker A, Genty D, Smart PL (1998) High-resolution records of soil humification and paleochmatic change from variations in speleothem luminescence excitation and emission wavelengths. Geology 26 903-906 Baker A, Ito E, Smart PL, McEwan R (1997) Elevated C in speleothem and imphcations for palaeo-vegetation studies. Chem Geol 136 263-270... 

Organic acid fluorescence. In a similar manner to trace constituents, such as Mg, Sr and P, concentrations of organic acids present in speleothem calcite are sufficient to observe variation at temporal scales of less than annual in some cases (e.g.. Baker et al. 1993, Shopov et al. 1994). Organic acids (humic and fulvic) are formed in the soil by humification, and transported to the cave void by percolating waters where they are entrapped in precipitating carbonates. Under certain circumstances, where precipitation patterns are strongly seasonal and the nature of vadose percolation is such that seasonal mixing is incomplete, bands with different luminescent intensities can be differentiated after excitation with UV radiation. In other cases, bands are not observable but secular... 

Shopov YY, Ford DC, Schwarcz HP (1994) Luminescent micro-banding in speleothems high-resolution chronology and paleoclimate. Geology 22 407-410... 

Shopov, Y.Y., Ford, D.C. and Schwarcz, H.P., 1994, Luminescent microbanding in speleothems High-resolution chronology and paleoclimate, Geo/ogy 22 407-410. 

White, W.B., 1997, Precise measurement of luminescence banding profiles in speleothems for paleoclimatic interpretation, Proc. 12th Internatl. Congress Speleol. 1 89-92. 

White, W.B. and Brennan,E.S., 1989, Luminescence of speleothems due to fulvic acid and other activators, Proc. 10th Internatl. Congress Speleol. pp. 212-214. 

Speleothems (stalagmites, stalactites, and flow-stones) are producing a tremendous range of reconstructions of different types of paleoclimatic parameters, including many quantitative records. Calcite speleothems display Inminescence, which is produced by calcinm salts of humic and fulvic acids derived from soils above the cave. The luminescence of speleothems depends exponentially on the solar insolation (if soil surface is heated directly by the Sun) or on the air temperature (if the cave is covered by forest or bush). Therefore, luminescence records represent solar insolation or temperature in the past. Luminescence of many speleothems is exhibited by annual bands much like tree rings. Distance between them is a quantitative proxy of annual precipitation in the past. 

Baker, A. and Bolton, L. (2000). Speleothem organic acid luminescence intensity ratios a new palaeoenvironmental proxy. Cave Karst Sci., 27,121-124. 

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