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

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 δ D 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 δ D and δ18O 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 d and δ18O isotopic compositions of measured water aliquots. Precision is better than 1.5 ‰ for δ D and 0.4 ‰ for δ18O for water measurements for an extended range (−210 to 0 ‰ for δ D and −27 to 0 ‰ for δ18O) 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.

[1]  Eric J. Fetzer,et al.  Water Vapor , 2014, Encyclopedia of Remote Sensing.

[2]  H. Vonhof,et al.  Measurement of δ18O and δ2H values of fluid inclusion water in speleothems using cavity ring-down spectroscopy compared with isotope ratio mass spectrometry. , 2013, Rapid communications in mass spectrometry : RCM.

[3]  J. Moerman,et al.  Diurnal to interannual rainfall δ18O variations in northern Borneo driven by regional hydrology , 2013 .

[4]  D. Fleitmann,et al.  New online method for water isotope analysis of fluid inclusions in speleothems , 2013 .

[5]  Peter K. Swart,et al.  Measurement of δ18O and δ2H values of fluid inclusion water in speleothems using cavity ring-down spectroscopy compared with isotope ratio mass spectrometry. , 2013, Rapid communications in mass spectrometry : RCM.

[6]  H. Wernli,et al.  Measuring variations of δ 18 O and δ 2 H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study , 2012 .

[7]  L. Wassenaar,et al.  Determination of the hydrogen isotopic compositions of organic materials and hydrous minerals using thermal combustion laser spectroscopy. , 2012, Analytical chemistry.

[8]  J. Escobar,et al.  Late Glacial temperature and precipitation changes in the lowland Neotropics by tandem measurement of δ18O in biogenic carbonate and gypsum hydration water , 2012 .

[9]  E. Villalobos,et al.  Interglacial Hydroclimate in the Tropical West Pacific Through the Late Pleistocene , 2012 .

[10]  Yang Wang,et al.  Speleothem calcite farmed in situ: Modern calibration of δ18O and δ13C paleoclimate proxies in a continuously-monitored natural cave system , 2011 .

[11]  R. Drysdale,et al.  13C18O clumping in speleothems: Observations from natural caves and precipitation experiments , 2011 .

[12]  D. Fleitmann,et al.  Pleistocene water intrusions from the Mediterranean and Caspian seas into the Black Sea , 2011 .

[13]  M. Bar-Matthews,et al.  Speleothem record of the last 180 ka in Villars cave (SW France): Investigation of a large δ18O shift between MIS6 and MIS5 , 2011 .

[14]  D. Fleitmann,et al.  Accurate analysis of noble gas concentrations in small water samples and its application to fluid inclusions in stalagmites , 2010 .

[15]  Andy Baker,et al.  Modern stalagmite δ18O: Instrumental calibration and forward modelling , 2010 .

[16]  W. Broecker,et al.  Ice Age Terminations , 2009, Science.

[17]  C. Spötl,et al.  Hydrogen and oxygen isotopes of water from inclusions in minerals: design of a new crushing system and on-line continuous-flow isotope ratio mass spectrometric analysis. , 2009, Rapid communications in mass spectrometry : RCM.

[18]  Colm Sweeney,et al.  Demonstration of high-precision continuous measurements of water vapor isotopologues in laboratory and remote field deployments using wavelength-scanned cavity ring-down spectroscopy (WS-CRDS) technology. , 2009, Rapid communications in mass spectrometry : RCM.

[19]  A. Knohl,et al.  Water vapor δ 2 H and δ 18 O measurements using off-axis integrated cavity output spectroscopy , 2009 .

[20]  D. Romanini,et al.  A Microdrop Generator for the Calibration of a Water Vapor Isotope Ratio Spectrometer , 2009 .

[21]  Eric R. Crosson,et al.  Cavity ring-down spectroscopy versus high-temperature conversion isotope ratio mass spectrometry; a case study on delta(2)H and delta(18)O of pure water samples and alcohol/water mixtures. , 2009, Rapid communications in mass spectrometry : RCM.

[22]  M. Lachniet,et al.  Climatic and environmental controls on speleothem oxygen-isotope values , 2009 .

[23]  E. Crosson,et al.  A cavity ring-down analyzer for measuring atmospheric levels of methane, carbon dioxide, and water vapor , 2008 .

[24]  D. Genty,et al.  Water release patterns of heated speleothem calcite and hydrogen isotope composition of fluid inclusions , 2008 .

[25]  H. Vonhof,et al.  A continuous-flow crushing device for on-line delta2H analysis of fluid inclusion water in speleothems. , 2006, Rapid communications in mass spectrometry : RCM.

[26]  Andy Baker,et al.  University of Birmingham Modification and preservation of environmental signals in speleothems , 2005 .

[27]  Patrick J. Mickler,et al.  Large kinetic isotope effects in modern speleothems , 2006 .

[28]  W. Brand,et al.  Continuous flow 2H/1H and 18O/16O analysis of water samples with dual inlet precision. , 2004, Rapid communications in mass spectrometry : RCM.

[29]  M. Bar-Matthews,et al.  Constraints on hydrological and paleotemperature variations in the Eastern Mediterranean region in the last 140 ka given by the δD values of speleothem fluid inclusions , 2004 .

[30]  S. Burns,et al.  Changing moisture sources over the last 330,000 years in Northern Oman from fluid-inclusion evidence in speleothems , 2003, Quaternary Research.

[31]  M. Leuenberger,et al.  Fast high-precision on-line determination of hydrogen isotope ratios of water or ice by continuous-flow isotope ratio mass spectrometry. , 2003, Rapid communications in mass spectrometry : RCM.

[32]  M. Leuenberger,et al.  On-line determination of oxygen isotope ratios of water or ice by mass spectrometry. , 2002, Analytical chemistry.

[33]  Z. Sharp,et al.  A rapid method for determination of hydrogen and oxygen isotope ratios from water and hydrous minerals , 2001 .

[34]  T. Brockwell,et al.  On-line high-precision stable hydrogen isotopic analyses on nanoliter water samples. , 2001, Analytical chemistry.

[35]  T. Atkinson,et al.  The recovery and isotopic measurement of water from fluid inclusions in speleothems , 2001 .

[36]  M. Bar-Matthews,et al.  D/H ratios of fluid inclusions of Soreq cave (Israel) speleothems as a guide to the Eastern Mediterranean Meteoric Line relationships in the last 120 ky , 2000 .

[37]  P. Smalley,et al.  The laser microprobe and its application to the study of C and O isotopes in calcite and aragonite , 1989 .

[38]  C. Yonge.  Stable Isotope Studies of Water Extracted from Speleothems , 1982 .

[39]  H. Schwarcz,et al.  D/H ratios in speleothem fluid inclusions: A guide to variations in the isotopic composition of meteoric precipitation? , 1979 .

[40]  H. Schwarcz,et al.  Stable Isotope Geochemistry of Speleothems and Cave Waters from the Flint Ridge-Mammoth Cave System, Kentucky: Implications for Terrestrial Climate Change during the Period 230,000 to 100,000 Years B.P. , 1978, The Journal of Geology.

[41]  P. J. Thompson,et al.  Stable isotope studies of fluid inclusions in speleothems and their paleoclimatic significance , 1976 .