Calibrating the glycerol dialkyl glycerol tetraether temperature signal in speleothems

Abstract

Palaeotemperature proxies based on glycerol dialkyl glycerol tetraethers (GDGTs) lipids have been established for marine and lacustrine environments, but there has been relatively little study of their application in speleothems. In this study we analyse the GDGT content of 33 speleothem samples from 16 different sites around the globe, and test whether proxies based on isoprenoid tetraethers (TEX 86 ) or branched tetraethers (MBT/CBT) are correlated with measured surface and cave mean annual air temperature (MAT). The results show that the TEX 86 has a strong relationship with measured temperature (r 2 = 0.78, standard error of the estimate 2.3°C, when calibrated with surface MAT). Furthermore, the MBT/CBT also showed a significant relationship with temperature (r 2 = 0.73, standard error of the estimate 2.7°C, when calibrated with surface MAT). Some issues remain requiring future work, in particular the development of a larger calibration sample set with measured cave temperature data, and the investigation of controls other than temperature on GDGT distribution, but overall the results indicate that GDGT based proxies derived from speleothems may be highly viable new methods for reconstructing continental palaeotemperatures.

A refined paleotemperature calibration for New Zealand limnic environments using differentiation of branched glycerol dialkyl glycerol tetraether (brGDGT) sources

“…; Table S2b) for direct comparison with lake sediment data to confirm whether lakes and their catchment soils represent strongly connected habitats for brGDGT‐synthesizing bacteria or unique bacterial habitats with a separate temperature adaptation as already implied from comparison of GDGT compositions (see above). This is in line with several other studies that have demonstrated that there is a pressing need for individual calibrations for different terrestrial environments such as soils, lakes, rivers or caves (Weijers et al ., ; Tierney and Russell, ; Tierney et al ., ; Wang et al ., ; Blyth and Schouten, ; Yang et al ., ).…”

Assessment of branched GDGTs as temperature proxies in sedimentary records from several small lakes in southwestern Greenland

“…Peterse et al, 2011;Huguet et al, 2012), stalagmites (e.g. Yang et al, 2011;Blyth and Schouten, 2013) and hot springs (e.g. Schouten et al, 2007).…”

Geochemical mapping of organic carbon in stalagmites using liquid-phase and solid-phase fluorescence

“…Since studies first demonstrated the presence of organic matter (OM) entrapped in calcite (Baker et al, 1996;Ramseyer et al, 1997), a number of organic components of speleothems being used as proxies for investigating changes in soils, vegetation, and climate (e.g., Baker et al, 1998;Blyth & Schouten 2013;Blyth et al 2011;Blyth et al, 2014;Bosle et al, 2014;Li et al, 2014;Perrette et al, 2005, Perrette et al, 2008Webb et al, 2014).…”