A continuous‐flow crushing device for on‐line δ²H analysis of fluid inclusion water in speleothems

Abstract

A method for the isotope analysis of fluid inclusion water in speleothem calcite is presented. The technique is based on a commercially available continuous-flow pyrolysis furnace (ThermoFinnigan TC-EA). The main adaptation made to the standard TC-EA configuration is the addition of a crusher and cold trap unit, which is connected to the carrier gas inlet at the top of the TC-EA reactor tube. A series of tests conducted with this device shows that: (1) standard waters, injected in the crusher, and passed through a cryogenic trapping routine, yield accurate delta(2)H values; (2) crushed cubes of speleothem calcite from two Peruvian caves with rather dissimilar seepage water delta(2)H values yield fluid inclusion delta(2)H values in good accordance with these drip waters. The clear advantage of this continuous-flow technique for fluid inclusion isotope analysis is that it is relatively quick compared with other techniques. Since the conditions of water sample introduction into the TC-EA are identical for delta(2)H and delta(18)O analysis, we expect that only limited adaptations to the extraction procedure are required to provide delta(18)O analysis of fluid inclusion samples with the same device.

Stable isotope compositions of speleothems from the last interglacial – Spatial patterns of climate fluctuations in Europe

“…These records have been dated by the U-Th series dating method providing numerical ages, making them valuable for paleoclimate studies on the LIG, although their geochemical compositions have not been evaluated in detail as yet (Govin et al, 2015). Besides conventional carbonate C and O isotope analyses, H and O isotope values of water trapped in the fluid inclusions of stalagmites have gained increasing importance in recent years as technical developments improved sampling resolution, analytical precision and throughput (Vonhof et al, 2006;van Breukelen et al, 2008;Dublyansky and Spötl, 2009;Griffiths et al, 2010;Wainer et al, 2011;Rowe et al, 2012;Arienzo et al, 2013;Ayalon et al, 2013;Affolter et al, 2014). The main advantage of fluid inclusion analyses is that -in contrast to C and O isotope ratios of the precipitating carbonate that depend on a large number of factors (see Fairchild and Baker, 2012) -H and O isotope compositions of the water are not fractionated during entrapment, and hence can directly reflect the composition of dripwater (Harmon and Schwarz, 1981;Yonge, 1982).…”

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

“…Analyses of both water isotopes in a unique measurement were achieved using the pyrolysis coupled to the IRMS technique and gas chromatography (Gehre et al, 2004;Sharp et al, 2001). More recently, the same method was adapted and modified to perform successful water isotope analysis of speleothem fluid inclusions (Vonhof et al, 2006;Dublyansky and Spötl, 2009). …”

“…To generate the water background, a procedure similar to the calibration protocol for atmospheric measurement is used (Iannone et al, 2009;Sturm and Knohl, 2010), and it requires the vaporisation of a water standard in a vaporisation system. Compared to the crushing device of the Amsterdam line (Vonhof et al, 2006), our line is used to investigate whether the removal of any cryogenic traps prior to the analysis is an advantage. This paper discusses the technical aspects of the newly designed line, the calibration of the laser instrument and the evaluation of the data.…”

Hydrological control of the dead carbon fraction in a Holocene tropical speleothem

“…Consequently, a highly productive and growing speleothem community has emerged, which in the last five years has resulted in a proliferation of new techniques and applications (e.g. Kluge et al, 2008;Blyth et al, 2011), substantial refinements to existing technologies (Vonhof et al, 2006;Woodhead et al, 2006;Dublyansky and Spötl, 2009), and a renewed interest in geochemical and physical modelling of speleothem-forming processes Wackerbarth et al, 2010;Dreybrodt and Scholz, 2011;Fohlmeister et al, 2011b).…”