An exploration of the utility of speleothem age distributions for palaeoclimate assessment

Weij, Rieneke; Woodhead, Jon; Hellström, John; Sniderman, J. M. Kale

doi:10.1016/j.quageo.2020.101112

Cited by 8 publications

(2 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The number below each period of speleothem deposition indicate the number of stalagmites that grew in each period and, in parentheses, the number of 230 Th/U age determinations used to define each period. At the bottom of the figure is a kernel density curve giving the age probability versus time (Sharman et al, 2018;Weij et al, 2020). component of the ITCZ, particularly during the last glacial period (Kanner et al, 2012;Wang et al, 2004).…”

Section: Climatic Controls On Speleothem Growth Periodsmentioning

confidence: 99%

Southern Hemisphere controls on ITCZ variability in southwest Madagascar over the past 117,000 years

Burns

McGee

Scroxton

et al. 2022

Quaternary Science Reviews

View full text Add to dashboard Cite

Section: Climatic Controls On Speleothem Growth Periodsmentioning

confidence: 99%

Southern Hemisphere controls on ITCZ variability in southwest Madagascar over the past 117,000 years

Burns

McGee

Scroxton

et al. 2022

Quaternary Science Reviews

View full text Add to dashboard Cite

“…The resulting array of corrected ages and their respective uncertainties was converted to probability density functions (PDFs) assuming a Gaussian distribution and summed per patch in order to compare with isochron dating results. Note that this approach was primarily chosen to visualise a realistic range of corrected ages and is not equivalent to similar probabilistic methods using kernel density estimates (Weij et al, 2020).…”

Section: Th/u Analysismentioning

confidence: 99%

²³⁰Th ∕ U isochron dating of cryogenic cave carbonates

et al. 2022

View full text Add to dashboard Cite

Cryogenic cave carbonates (CCCs) are a type of speleothem, typically dated with 230 Th/U disequilibrium methods, that provide evidence of palaeo-permafrost conditions. In the field, CCCs occur as distinct patches of millimetre-to centimetre-sized loose crystals and crystal aggregates on the floors of cave chambers, so they lack a framework that would allow ages to be validated by stratigraphic order. Correction factors for the initial 230 Th ( 230 Th 0 ) are often based on the bulk-earth-derived initial 230 Th/ 232 Th activity ratio (( 230 Th/ 232 Th) 0 ), which is a well-established approach when 230 Th 0 is moderately low. For samples with elevated levels of 230 Th 0 , however, accuracy can be improved by constraining ( 230 Th/ 232 Th) 0 independently. Here, we combine detailed morphological observations from three CCC patches found in Water Icicle Close Cavern in the Peak District (UK) with 230 Th/U analyses. We find that individual CCC crystals show a range of morphologies that arise from non-crystallographic branching in response to the chemical evolution of the freezing solution. Results of 230 Th/U dating indicate that samples with a large surface area relative to the sample volume are systematically more affected by contamination with 230 Th 0 . By fitting isochrons to these results, we test whether the CCCs in a patch formed during the same freezing event, and demonstrate that ( 230 Th/ 232 Th) 0 can deviate substantially from the bulk-earth-derived value and can also vary between the different CCC patches. Where CCCs display elevated 230 Th 0 , isochrons are a useful tool to constrain ( 230 Th/ 232 Th) 0 and obtain ages with improved accuracy. Detritus absorbed to the crystal surface is shown to be the most likely source of 230 Th 0 . Our results suggest that some previously published CCC ages may merit re-assessment, and we provide suggestions on how to approach future dating efforts.

show abstract

Timescales of speleogenesis in an evolving syngenetic karst: The Tamala Limestone,Western Australia

et al. 2022

View full text Add to dashboard Cite

An exploration of the utility of speleothem age distributions for palaeoclimate assessment

Cited by 8 publications

References 52 publications

Southern Hemisphere controls on ITCZ variability in southwest Madagascar over the past 117,000 years

Southern Hemisphere controls on ITCZ variability in southwest Madagascar over the past 117,000 years

²³⁰Th ∕ U isochron dating of cryogenic cave carbonates

Timescales of speleogenesis in an evolving syngenetic karst: The Tamala Limestone,Western Australia

Contact Info

Product

Resources

About

An exploration of the utility of speleothem age distributions for palaeoclimate assessment

Cited by 8 publications

References 52 publications

Southern Hemisphere controls on ITCZ variability in southwest Madagascar over the past 117,000 years

Southern Hemisphere controls on ITCZ variability in southwest Madagascar over the past 117,000 years

230Th ∕ U isochron dating of cryogenic cave carbonates

Timescales of speleogenesis in an evolving syngenetic karst: The Tamala Limestone,Western Australia

Contact Info

Product

Resources

About

²³⁰Th ∕ U isochron dating of cryogenic cave carbonates