A new record of environmental proxies for Cueva Victoria, Spain

Secondary mineral deposits in caves, such as stalagmites, constitute valuable paleoclimate archives because they are largely protected from degradation due to stable in-cave conditions and can be precisely dated up to 600,000 years using ²³⁰Th/U-dating. [1] In addition to established climate proxies, such as stable isotopes and trace elements, organic proxies have become increasingly attractive in recent years for investigating local vegetation and soil dynamics. [2]

 

Lignin, a biopolymer, is one of the main constituents of higher plants and consists of three monomeric units: sinapyl-, coniferyl-, and coumaryl alcohol. Lignin can be degraded into its monomeric units by alkaline CuSO₄-oxidation [3]. Determination of the ratios among different oxidation products in a speleothem allows the reconstruction of the type of vegetation above the cave [4].

 

Biomass burning events are major sources of atmospheric particulate matter that influences global and local climate. [5] Investigating fire proxies in paleoclimate archives may therefore help to determine the interactions of climate, hydrology, and fire activity. Levoglucosan, an anhydrosugar, naturally only originates from the combustion of cellulose and thus constitutes a biomass burning marker. To date, no data on levoglucosan in speleothems have been published, whereas the anhydrosugar has already been utilised in other paleoclimate archives, such as sediments and ice cores. [2,5]

 

Here we present preliminary results for samples from two flowstone cores from Cueva Victoria in south-eastern Spain. The investigated samples cover MIS 1 and 7-11. Speleothems from this cave are known to have grown in intervals for at least 450 000 years. [6] Due to the semi-arid climate in this region the speleothems have mostly grown during interglacials, thereby responding and documenting changes in paleoclimate. We aim to reconstruct vegetation changes, investigate the occurrence of fires, and compare the results with existing δ¹³C and δ¹⁸O data.

 

[1] D. Scholz, D. Hoffmann, Quat. Sci. J. 57 (2008) 52–76 [2] A. Blyth et al. Quat. Sci. Rev. 149 (2016) 1-17. [3] G. Yan, K. Kaiser, Anal. Chem. 90 (2018) 9289–9295. [4] C.N. Jex, G.H. et.al. Quat. Sci. Rev. 87 (2014) 46–59. [5] P. Yao et al. J. of Glaciology 59 (2013) 599-611 [5] V. O. Elias et al. Geochim. et Cosmochim. Acta 65 (2001) 267-272. [6] L. Gibert, C. Ferrandez-Canadell (eds) (2015) Geology and Paleontology of Cueva Victoria (Mastia 11–13). Cartagena: Ayuntamiento de Cartagena.