Uranium-series Chronology and Environmental Applications of Speleothems

Richards, David A.; Dorale, Jeffrey A.

doi:10.2113/0520407

Cited by 300 publications

(191 citation statements)

References 217 publications

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“…All speleothems were dated with the UraniumThorium disequilibrium method (Hellstrom, 2003;Richards & Dorale, 2003;Scholz & Hoffmann, 2008) at the School of Earth Science -University of Melbourne, following the protocol set up in Hellstrom (2006) and improved in Drysdale et al (2012).…”

Section: Carbonate Speleothems In Gypsum Caves As Palaeoclimate and Pmentioning

confidence: 99%

Evaporite karst in Italy: a review

Waele¹,

Piccini²,

Columbu³

et al. 2017

IJS

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Abstract:Although outcropping rarely in Italy, evaporite (gypsum and anhydrite) karst has been described in detail since the early 20 th century. Gypsum caves are now known from almost all Italian regions, but are mainly localised along the northern border of the Apennine chain (Emilia Romagna and Marche), Calabria, and Sicily, where the major outcrops occur. Recently, important caves have also been discovered in the underground gypsum mines in Piedmont. During the late 80s and 90s several multidisciplinary studies were carried out in many gypsum areas, resulting in a comprehensive overview, promoting further research in these special karst regions. More recent and detailed studies focused on the gypsum areas of Emilia-Romagna and Sicily. Sinkholes related to Permian-Triassic gypsum have been studied in Friuli Venezia Giulia. This article reviews the state of the art regarding different aspects of evaporite karst in Italy focusing on the main new results.

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Section: Carbonate Speleothems In Gypsum Caves As Palaeoclimate and Pmentioning

confidence: 99%

Evaporite karst in Italy: a review

Waele¹,

Piccini²,

Columbu³

et al. 2017

IJS

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“…Hellstrom et al, 1998), the internal stratigraphy of flowstones is commonly complex because of non-uniform calcite growth rates across the flowstone surface and flow-switching behaviour. They tend to have high impurity contents; in such cases they can be difficult to date by U-series methods (Richards and Dorale, 2003).…”

Section: The Environment and Nature Of Speleothemsmentioning

confidence: 99%

“…This way of synthesizing the interpretation of speleothem records is new and is designed to complement and build on several excellent recent reviews, including those of Darling (2004) and Darling et al (2005) on water isotopes, McDermott (2004) and McDermott et al (2005) on stable isotopes in speleothems, Richards and Dorale (2003) and Dorale et al (2004) on uranium-series dating of speleothems, Harmon et al (2004) on modern calibrations, McGarry and Baker (2000) and McGarry and Caseldine (2004) on organic components, and Lauritzen (2003) and White (2004) on the approaches to the generation of speleothem palaeoclimate records. A companion article (Fairchild et al, 2006) emphasizes the geomorphological context of speleothems, and discusses their physical fabrics and lamination in relation to their geochemistry, but does not deal with time series issues.…”

Section: Introductionmentioning

confidence: 99%

Modification and preservation of environmental signals in speleothems

Fairchild

Smith

Baker

et al. 2006

Earth-Science Reviews

729

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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“…Beck et al, 2001;Weyhenmeyer et al, 2003;Dorale et al, 2008;McDermott et al, 2008;Hoffmann et al, 2010;Southon et al, 2012). Speleothems hold some key advantages over floating tree rings, varved chronologies, and marine records: (1) They can be precisely and absolutely dated using U-Th methods (Richards and Dorale, 2003); (2) Their fast growth rates, highly resolvable stratigraphy, and excellent preservation allow for often continuous highresolution 14 C measurement over the entire 14 C dating range; (3) they are widely used for paleoclimate reconstruction (Fairchild et al, 2006) so access to numerous U-Th dated samples is possible and will allow for replication of records and direct comparison with climate proxy data. There are, however, several complicating factors affecting speleothem-based radiocarbon calibrations stemming from the way that speleothems are formed.…”

Section: Speleothem-based Records Of Atmospheric Radiocarbonmentioning

confidence: 99%

Assessing influences on speleothem dead carbon variability over the Holocene: Implications for speleothem-based radiocarbon calibration

Noronha¹,

Johnson²,

et al. 2014

Earth and Planetary Science Letters

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Recently, it has been shown that U-Th dated speleothems may provide a valuable archive of atmospheric radiocarbon ( 14 C), but the reliability of these records is dependent upon the stability of the dead carbon proportion (DCP) derived from the soil and bedrock. In order to assess climatic influences on speleothem DCP, we have investigated DCP variability over the Holocene interval where atmospheric 14 C is well known based on dendrochronologically dated tree rings by conducting 14 C measurements on a U-Th dated stalagmite (HS4) from Heshang Cave, Hubei Province, China (30 • 27 N, 110 • 25 E; 294 m) spanning 0.5-9.6 ka. We investigated climatic controls on DCP, and found that DCP in HS4 has an average value over the Holocene of 10.3 ± 1.5%, with an average age offset from atmospheric radiocarbon of 875 ± 130 years, and displays a response to both precipitation increases and decreases. HS4 DCP increases during the wetter mid-Holocene interval (∼5.5-7.1 ka), likely reflecting a shift to more closed-system dissolution in response to increased soil moisture. DCP decreases during the 8.2 ka event, a time period of dry conditions at Heshang Cave, though the lower amplitude of this shift indicates that DCP may be less sensitive to dry events. Speleothems are potentially valuable archives of atmospheric radiocarbon, especially in older portions of the 14 C calibration curve where knowledge of atmospheric 14 C is limited, however minor climatic influences on DCP could introduce uncertainties of several hundred years to calibrated ages.

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Uranium-series Chronology and Environmental Applications of Speleothems

Cited by 300 publications

References 217 publications

Evaporite karst in Italy: a review

Evaporite karst in Italy: a review

Modification and preservation of environmental signals in speleothems

Assessing influences on speleothem dead carbon variability over the Holocene: Implications for speleothem-based radiocarbon calibration

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