Late Quaternary Paleotemperatures Derived from a Speleothem from Cango Caves, Cape Province, South Africa

Talma, A.S.; Vogel, J. C.

doi:10.1016/0033-5894(92)90082-t

Cited by 301 publications

(229 citation statements)

References 22 publications

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“…Slow speleothem growth implies complete degassing, whereas variation in the amount of degassing might otherwise have an influence on δ 13 C (Schwarcz, 1986;Bar-Matthews et al, 1996). C4/C3 variations were also thought to control Holocene δ 13 C variations in NE South Africa (Talma and Vogel, 1992;Lee-Thorp et al, 2001). In other cases, the vegetation amount has been hypothesized to control speleothem δ 13 C composition.…”

Section: Carbon Isotopesmentioning

confidence: 99%

Modification and preservation of environmental signals in speleothems

Fairchild

Smith

Baker

et al. 2006

Earth-Science Reviews

737

506

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Speleothems are primarily studied in order to generate archives of climatic change and results have led to significant advances in identifying and dating major shifts in the climate system. However, the climatological meaning of many speleothem records cannot be interpreted unequivocally; this is particularly so for more subtle shifts and shorter time periods, but the use of multiple proxies and improving understanding of formation mechanisms offers a clear way forward.An explicit description of speleothem records as time series draws attention to the nature and importance of the signal filtering processes by which the weather, the seasons and longer-term climatic and other environmental fluctuations become encoded in speleothems. We distinguish five sources of variation that influence speleothem geochemistry: atmospheric, vegetation/soil, karstic aquifer, primary speleothem crystal growth and secondary alteration and give specific examples of their influence. The direct role of climate diminishes progressively through these five factors.We identify and review a number of processes identified in recent and current work that bear significantly on the conventional interpretation of speleothem records, for example: 1) speleothem geochemistry can vary seasonally and hence a research need is to establish the proportion of growth attributable to different seasons and whether this varies over time.2) whereas there has traditionally been a focus on monthly mean δ 18 O data of atmospheric moisture, current work emphasizes the importance of understanding the synoptic processes that lead to characteristic isotope signals, since changing relative abundance of different weather types might 1 Corresponding author, fax +44(0)1214145528, E-mail: i.j.fairchild@bham.ac.uk control their variation on the longer-term. 3) the ecosystem and soil zone overlying the cave fundamentally imprint the carbon and trace element signals and can show characteristic variations with time. 4) new modelling on aquifer plumbing allows quantification of the effects of aquifer mixing. 5) recent work has emphasized the importance and seasonal variability of CO 2 -degassing leading to calcite precipitation upflow of a depositional site on carbon isotope and trace element composition of speleothems. 6) Although much is known about the chemical partitioning between water and stalagmites, variability in relation to crystal growth mechanisms and kinetics is a research frontier. 7) Aragonite is susceptible to conversion to calcite with major loss of chemical information, but the controls on the rate of this process are obscure.Analytical factors are critical to generate high-resolution speleothem records. A variety of methods of trace element analysis are available, but standardization is a common problem with the most rapid methods. New stable isotope data on Irish stalagmite CC3 compares rapid laser-ablation techniques with the conventional analysis of micromilled powders and ion microprobe methods. A high degree of comparability between techniques ...

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Section: Carbon Isotopesmentioning

confidence: 99%

Modification and preservation of environmental signals in speleothems

Fairchild

Smith

Baker

et al. 2006

Earth-Science Reviews

737

506

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“…Oxygen isotope data (d 18 O) of stalagmites from the Cango Cave (transition between summer and winter rainfall region) and the Cold Air Cave (summer rainfall region) in southern and northeastern South Africa (Talma & Vogel 1992;Holmgren et al 2003), d…”

Section: Multi-decadal To Centennial Variabilitymentioning

confidence: 99%

Nutrient regime and upwelling in the northern Benguela since the middle Holocene in a global context - a multi-proxy approach

et al. 2011

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The last 5500 years of climate change and environmental response in the northern Benguela Coastal Upwelling are reconstructed by means of three sediment cores from the inner shelf off central Namibia. The study is based on nutrient (delta(15)N, delta(13)C) and productivity proxies (accumulation rates of total organic carbon; AR(TOC)). Reconstructed sea surface temperatures (alkenone-derived SST) and temperatures at subsurface depths (T(delta 18O); based on tests of planktonic foraminifers) reflect the physical boundary conditions. The selection of proxy indicators proved a valuable basis for robust palaeo-climatic reconstructions, with the resolution ranging from multi-decadal (NAM1) over centennial (core 178) to millennial scale (core 226620). The northern Benguela experienced pronounced and rapid perturbation during the middle and late Holocene, and apparently, not all are purely local in character. In fact, numerous correlations with records from the adjacent South African subcontinent and the northern hemisphere testify to global climatic teleconnections. The Holocene Hypsithermal, for instance, is just as evident as the Little Ice Age (LIA) and the Roman Warm Period. The marked SST-rise associated with the latter is substantiated by other marine and terrestrial data from the South African realm. The LIA (at least its early stages) manifests itself in intensified winds and upwelling, which accords with increased rainfall receipts above the continental interior. It appears that climate signals are transferred both via the atmosphere and ocean. The combined analysis of SST and T(delta 18O) proved a useful tool in order to differentiate between both pathways. SSTs are primarily controlled by the intensity of atmospheric circulation features, reflecting changes of upwelling-favourable winds. T(delta 18O) records the temperature of the source water and often correlates with global ocean conveyor speed due to varying inputs of warm Agulhas Water. It seems as though conveyor slowdown or acceleration not only affected the temperature of the source water but also its nutrient content. This relationship between source water quality and conveyor speed is already known from glacial times

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“…To date, attempts to recover temperature proxies from stalagmites have focused on stable isotopes in the calcite matrix (e.g. Gascoyne et al, 1980;Talma and Vogel, 1992;Mangini et al, 2005), clumped isotope thermometry of the calcite (Affek et al, 2008;Meckler et al, 2009), or isotopic or noble gas analysis of fluid inclusions (Schwarcz and Harmon, 1976;Genty et al, 2002;van Breukelen et al, 2008;Scheidegger et al, 2010). Analysis of d 18 O in stalagmite calcite is now largely recognised as being an unreliable proxy for temperature due to the large number of confounding factors that affect the signal (McDermott, 2004).…”

Section: Introductionmentioning

confidence: 99%

Calibrating the glycerol dialkyl glycerol tetraether temperature signal in speleothems

Blyth¹,

Schouten²

2013

Geochimica et Cosmochimica Acta

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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.

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Late Quaternary Paleotemperatures Derived from a Speleothem from Cango Caves, Cape Province, South Africa

Cited by 301 publications

References 22 publications

Modification and preservation of environmental signals in speleothems

Modification and preservation of environmental signals in speleothems

Nutrient regime and upwelling in the northern Benguela since the middle Holocene in a global context - a multi-proxy approach

Calibrating the glycerol dialkyl glycerol tetraether temperature signal in speleothems

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