Water release patterns of heated speleothem calcite and hydrogen isotope composition of fluid inclusions

Verheyden, Sophie; Genty, Dominique; Cattani, O.; Breukelen, Martin R. van

doi:10.1016/j.chemgeo.2007.10.019

Cited by 27 publications

(33 citation statements)

References 19 publications

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“…Several studies showed a large fractionation of up to 30 ‰ for δD in comparison with parent cave drip waters (Yonge, 1982;Matthews et al, 2000;McGarry et al, 2004). No fractionation is observed when the speleothem sample is heated to a maximal temperature of 400 • C (Verheyden et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

New online method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS)

2014

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Abstract.A new online method to analyse water isotopes of speleothem fluid inclusions using a wavelength scanned cavity ring down spectroscopy (WS-CRDS) instrument is presented. This novel technique allows us simultaneously to measure hydrogen and oxygen isotopes for a released aliquot of water. To do so, we designed a new simple line that allows the online water extraction and isotope analysis of speleothem samples. The specificity of the method lies in the fact that fluid inclusions release is made on a standard water background, which mainly improves the δD robustness.To saturate the line, a peristaltic pump continuously injects standard water into the line that is permanently heated to 140 • C and flushed with dry nitrogen gas. This permits instantaneous and complete vaporisation of the standard water, resulting in an artificial water background with well-known δD and δ 18 O values. The speleothem sample is placed in a copper tube, attached to the line, and after system stabilisation it is crushed using a simple hydraulic device to liberate speleothem fluid inclusions water. The released water is carried by the nitrogen/standard water gas stream directly to a Picarro L1102-i for isotope determination. To test the accuracy and reproducibility of the line and to measure standard water during speleothem measurements, a syringe injection unit was added to the line.Peak evaluation is done similarly as in gas chromatography to obtain δD and δ 18 O isotopic compositions of measured water aliquots. Precision is better than 1.5 ‰ for δD and 0.4 ‰ for δ 18 O for water measurements for an extended range (−210 to 0 ‰ for δD and −27 to 0 ‰ for δ 18 O) primarily dependent on the amount of water released from speleothem fluid inclusions and secondarily on the isotopic composition of the sample. The results show that WS-CRDS technology is suitable for speleothem fluid inclusion measurements and gives results that are comparable to the isotope ratio mass spectrometry (IRMS) technique.

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Section: Introductionmentioning

confidence: 99%

New online method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS)

2014

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“…The vacuum line and samples were held at about 80 °C to remove the adsorptively bound water from the samples and the line. In order to avoid any thermal decrepitation of the inclusions and diffusion of H 2 O out of the inclusions that may occur at 100 °C (Verheyden et al, 2008), the sample holder and samples were never heated to more than 85 °C. After vacuum pumping the sample and the vacuum line was continuously flushed with helium, maintaining pressure of several hundreds of mbar.…”

Section: Analyses Of Liquid Water Samples and Inclusion-hosted Wmentioning

confidence: 99%

“…Ostwald ripening has been proposed (Frisia et al, 2010) as a responsible mechanism for crystal-size coarsening, although purely on the basis of optical microscopy characteristics. Besides altering the carbonate's stable isotope and trace element compositions, diagenetic alteration and recrystallization may influence the isotopic compositions of inclusionhosted water whose investigations became one of the most promisingly developing fields in speleothem research in the last decade (Vonhof et al, 2006;van Breukelen et al, 2008;Dublyansky and Spötl, 2009;Griffiths et al, 2010;Wainer et al, 2010;Rowe et al, 2012;Arienzo et al, 2013;Ayalon et al, 2013;Affolter et al, 2014). The stable H and O isotope ratios of inclusion-hosted water are thought to be preserved after the inclusion entrapment in speleothems (Harmon and Schwarz, 1981;Yonge, 1982), as they rarely suffer late-stage alterations and isotope exchange at usual cave temperatures is negligible.…”

Section: Introductionmentioning

confidence: 99%

Recrystallization-induced oxygen isotope changes in inclusion-hosted water of speleothems – Paleoclimatological implications

Demény

Czuppon

Kern

et al. 2016

Quaternary International

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The issue of diagenetic alteration of carbonate deposits in caves (speleothems) has gained increasing importance in recent years, as this process has serious consequences for speleothembased paleoclimate studies. In this study stable hydrogen and oxygen isotope data of water trapped in fluid inclusions were collected for recently forming stalagmites and flowstones in order to determine how dripwater compositions are reflected and preserved in the inclusion water compositions. Hydrogen isotope compositions were found to reflect dripwater values, whereas the oxygen isotope data were increasingly shifted from the local dripwater compositions with the time elapsed after deposition. The δ 18 O data are correlated with X-Ray diffraction full width at half maximum values (related to crystal domain size and lattice strain),suggesting that the oxygen isotope shift is related to recrystallization of calcite. Transmission electron microscope analyses detected the presence of nanocrystalline (<50 nm) calcite, whose crystallization to coarser-grained calcite crystals (>200 nm) may have induced re-equilibration between the carbonate and the trapped inclusion water. The Ostwald ripening process provides an explanation for unexpectedly low oxygen isotope compositions in the inclusion water. The detected diagenetic alteration and its isotopic effects should be taken into consideration during sampling strategies and data evaluation as speleothems containing nanocrystalline calcite during their deposition are prone to late-stage oxygen isotope water-carbonate re-equilibration, which may shift the oxygen isotope composition of the inclusion water to more depleted values while the hydrogen isotope composition remains intact.

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“…Therefore, among HS4 laminations, the bright porous band should be formed in summer, whereas dark bands should be formed in winter. The degree of porosity and inclusions in bright parts of the speleothem is higher than that in darker parts (Verheyden et al, 2008). This indicates that the porosity of HS4 in summer is higher than it is in winter, suggesting besides the seasonal changes, HS4 SIMS δ 18 O also records the porosity seasonal differences, which makes δ 18 O vales more negative during the summer and magnifies the seasonal differences of δ 18 O.…”

Section: Comparison Between Conventional and Sims δ 18 O Of Hs4mentioning

confidence: 87%

Speleothem annual layers revealed by seasonal SIMS δ 18O measurements

Yu-hui

Tang

Ling

et al. 2015

Sci. China Earth Sci.

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In-situ seasonal δ 18 O measurements of section 236.3-235.6 cm of speleothem HS4, from Qingjiang Valley of the Middle reaches of Yangtze River, China, were performed by an Secondary Ionization Mass Spectrometry (SIMS) with Oka (Chinese primary calcite standard GBW04481) and UWC-3 (international calcite standard from University of Wisconsin). The potential of using SIMS δ 18 O measurements to establish speleothem time series has been explored and the differences between conventional and SIMS δ 18 O values have been discussed. During a 3-day period, UWC-3 δ 18 O has been measured on Cameca IMS 1280 Ion Microprobe Mass Spectrometer against "Oka" external standard. The measured mean value of UWC-3 (δ 18 O VPDB = 17.85‰±0.22‰, 1SD) matches well with its recommended value (δ 18 O VPDB =17.83‰0.08‰), suggesting that the instrument was stable. The same method applied on HS4 produced δ 18 O measurements at seasonal resolution with distinct annual cycles and the total cycle number in agreement with that from Mg/Ca cycles and lamination layer counting of the same section, so it offers an alternative for accessing speleothem time series. However, compared with conventional δ 18 O values of HS4, SIMS δ 18 O values are more negative by 0.90‰ with larger seasonal variation. The main reasons might come from the micro-cracks, micro-pores or liquid inclusions existing in HS4, and organic materials in the speleothem might be another factor affecting the SIMS δ 18 O values, indicating that to obtain reliable speleothem SIMS δ 18 O values, both compaction and purity of samples are crucial.

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Water release patterns of heated speleothem calcite and hydrogen isotope composition of fluid inclusions

Cited by 27 publications

References 19 publications

New online method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS)

New online method for water isotope analysis of speleothem fluid inclusions using laser absorption spectroscopy (WS-CRDS)

Recrystallization-induced oxygen isotope changes in inclusion-hosted water of speleothems – Paleoclimatological implications

Speleothem annual layers revealed by seasonal SIMS δ 18O measurements

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