Correspondence between glass-FT and 14C ages of silicic pyroclastic flow deposits sourced from Maninjau caldera, west-central Sumatra

Alloway, Brent V.; Pribadi, Agung; Westgate, John A.; Bird, Michael I.; Fifield, L.K.; Hogg, Alan G.; Smith, I. E.

doi:10.1016/j.epsl.2004.08.014

Cited by 54 publications

(43 citation statements)

References 17 publications

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“…The archeological charcoal was found in pyroclastic deposits at Maninjau, Sumatra (Alloway et al 2004) and had an F 14 C = 0.003 ± 0.001 (ETH-50456) whereas the laboratory charcoal was obtained from the pyrolysis of chestnut woodchips under controlled conditions in the laboratory (Hammes et al 2006) and had an F 14 C = 1.149 ± 0.004 (ETH-50457). For both samples, bulk 14 C values were determined after acid-base-acid pretreatment ahead of the analysis to remove extraneous organic matter (Gierga et al 2014).…”

Section: Overviewmentioning

confidence: 99%

Comprehensive radiocarbon analysis of benzene polycarboxylic acids (BPCAs) derived from pyrogenic carbon in environmental samples

et al. 2017

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ABSTRACT. Compound-specific radiocarbon analysis (CSRA) of benzene polycarboxylic acids (BPCAs) yields molecular-level, source-specific information necessary to constrain isotopic signatures of pyrogenic carbon. However, the purification of individual BPCAs requires a multistep procedure that typically results in only microgram quantities of the target analyte(s). Such small samples are highly susceptible to contamination by extraneous carbon, which needs to be minimized and carefully accounted for in order to yield accurate results. Here, we undertook comprehensive characterization and quantification of contamination associated with molecular radiocarbon ( 14 C) BPCA analyses through systematic processing of multiple authentic standards with both fossil and modern 14 C signatures at various concentrations. Using this approach, we precisely apportion the contribution of extraneous carbon with respect to the four implemented subprocedures. Assuming a constant source and quantity of extraneous carbon we correct and statistically evaluate uncertainties in resulting 14 C data. Subsequently, we examine the results of triplicate analyses of reference materials representing four different environmental matrices (sediment, soil, aerosol, riverine natural organic matter) and apportion their BPCA sources in terms of carbon residues derived from biomass or fossil fuel combustion. This comprehensive approach to CSRA facilitates retrieval of robust 14 C data, with application in environmental studies of the continuum of pyrogenic carbon.

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Section: Overviewmentioning

confidence: 99%

Comprehensive radiocarbon analysis of benzene polycarboxylic acids (BPCAs) derived from pyrogenic carbon in environmental samples

et al. 2017

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“…Because the ages of geomagnetic polarity transition zones are well known for the Quaternary period, magnetopolarity information provides an independent means of checking numerical ages obtained on tephras by radiometric methods or by orbital tuning (Black et al, 1996;Naish et al, 1998;Westgate et al, 2001;Alloway et al, 2004bAlloway et al, , 2007aCassata et al, 2010). The geomagnetic polarity sequence registered in sediments encapsulating a tephra thus provides a useful signature for correlation purposes as an age-equivalence dating tool (Verosub, 1981;Rogers and Larson, 1992;Sarna-Wojcicki et al, 1997;Merrill and McFadden, 2005;Deino et al, 2010).…”

Section: Magnetostratigraphymentioning

confidence: 99%

Tephrochronology and its application: A review

Lowe

2011

Quaternary Geochronology

650

535

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Tephrochronology (from tephra, Gk "ashes") is a unique stratigraphic method for linking, dating, and synchronizing geological, palaeoenvironmental, or archaeological sequences or events. As well as utilizing the Law of Superposition, tephrochronology in practise requires tephra deposits to be characterized (or "fingerprinted") using physical properties evident in the field together with those obtained from laboratory analyses. Such analyses include mineralogical examination (petrography) or geochemical analysis of glass shards or crystals using an electron microprobe or other analytical tools including laser-ablation-based mass spectrometry or the ion microprobe. The palaeoenvironmental or archaeological context in which a tephra occurs may also be useful for correlational purposes. Tephrochronology provides greatest utility when a numerical age obtained for a tephra or cryptotephra is transferrable from one site to another using stratigraphy and by comparing and matching inherent compositional features of the deposits with a high degree of likelihood. Used this way, tephrochronology is an age-equivalent dating method that provides an exceptionally precise volcanic-event stratigraphy. Such age transfers are valid because the primary tephra deposits from an eruption essentially have the same short-lived age everywhere they occur, forming isochrons very soon after the eruption (normally within a year).As well as providing isochrons for palaeoenvironmental and archaeological reconstructions, tephras through their geochemical analysis allow insight into volcanic and magmatic processes, and provide a comprehensive record of explosive volcanism and recurrence rates in the Quaternary (or earlier) that can be used to establish time-space relationships of relevance to volcanic hazard analysis.The basis and application of tephrochronology as a central stratigraphic and geochronological tool for Quaternary studies are presented and discussed in this review. Topics covered include principles of tephrochronology, defining isochrons, tephra nomenclature, mapping and correlating tephras from proximal to distal locations at metre-through to sub-3 millimetre-scale, cryptotephras, mineralogical and geochemical fingerprinting methods, numerical and statistical correlation techniques, and developments and applications in dating including the use of flexible depositional age-modelling techniques based on Bayesian statistics.Along with reference to wide-ranging examples and the identification of important recent advances in tephrochronology, such as the development of new geoanalytical approaches that enable individual small glass shards to be analysed near-routinely for major, trace, and rare-earth elements, potential problems such as miscorrelation, erroneous-age transfer, and tephra reworking and taphonomy (especially relating to cryptotephras) are also examined. Some of the challenges for future tephrochronological studies include refining geochemical analytical methods further, improving understanding of cryptotephra dis...

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“…Its precise dating using conventional AMS demonstrated that it lacked 14 C and had an age of ca. 50 ka BP (Alloway et al, 2004;Ascough et al, 2009). The modern analog ('modern char') was produced from chestnut wood (Castanea sativa) from a single tree cut in a forest in Southern Switzerland.…”

Section: Process Standardsmentioning

confidence: 99%

“…The archaeological charcoal sample ('fossil char') was from in situ charred trees sampled from paroxysmal flow deposits in the Maninjau caldera in West-Central Sumatra (Alloway et al, 2004). Its precise dating using conventional AMS demonstrated that it lacked 14 C and had an age of ca.…”

Section: Process Standardsmentioning

confidence: 99%

Purification of fire derived markers for μg scale isotope analysis (δ13C, Δ14C) using high performance liquid chromatography (HPLC)

Gierga

Schneider

Wiedemeier

et al. 2014

Organic Geochemistry

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Black carbon (BC) is the residue of incomplete biomass combustion. It is ubiquitous in nature and, due to its relative persistence, is an important factor in Earth's slow-cycling carbon pool. This resistant nature makes pure BC one of the most used materials for ¹C dating to elucidate its formation date or residence time in the environment. However, most BC samples cannot be physically separated from their matrices, precluding accurate ¹C values. Here we present a method for radiocarbon dating of the oxidation products of BC, benzene polycarboxylic acids, thereby circumventing interference from extraneous carbon. Individual compounds were isolated using high performance liquid chromatography (HPLC) and converted to CO via wet chemical oxidation for ¹³C and ¹C isotope analysis. A detailed assessment was performed to identify and quantify sources of extraneous carbon contamination using two process standards with distinct isotopic signatures. The average blank was 1.6 ± 0.7 g C and had an average radiocarbon content of 0.90 ± 0.50 F¹C. We successfully analyzed the ¹C content of individual benzene polycarboxylic acids with a sample size as small as 20-30 g C after correcting for the presence of the average blank. The combination of ¹³C and F¹C analysis helps interpret the results and enables monitoring of extraneous carbon contribution in a fast and cost efficient way. Such a molecular approach to radiocarbon dating of BC residues enables the expansion of isotopic BC studies to samples that have either been too small or strongly affected by non-fire derived carbon. a b s t r a c tBlack carbon (BC) is the residue of incomplete biomass combustion. It is ubiquitous in nature and, due to its relative persistence, is an important factor in Earth's slow-cycling carbon pool. This resistant nature makes pure BC one of the most used materials for 14 C dating to elucidate its formation date or residence time in the environment. However, most BC samples cannot be physically separated from their matrices, precluding accurate 14 C values. Here we present a method for radiocarbon dating of the oxidation products of BC, benzene polycarboxylic acids, thereby circumventing interference from extraneous carbon. Individual compounds were isolated using high performance liquid chromatography (HPLC) and converted to CO 2 via wet chemical oxidation for 13 C and 14 C isotope analysis. A detailed assessment was performed to identify and quantify sources of extraneous carbon contamination using two process standards with distinct isotopic signatures. The average blank was 1.6 ± 0.7 lg C and had an average radiocarbon content of 0.90 ± 0.50 F 14 C. We successfully analyzed the 14 C content of individual benzene polycarboxylic acids with a sample size as small as 20-30 lg C after correcting for the presence of the average blank.The combination of d 13 C and F 14 C analysis helps interpret the results and enables monitoring of extraneous carbon contribution in a fast and cost efficient way. Such a molecular approach to radiocarb...

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Correspondence between glass-FT and 14C ages of silicic pyroclastic flow deposits sourced from Maninjau caldera, west-central Sumatra

Cited by 54 publications

References 17 publications

Comprehensive radiocarbon analysis of benzene polycarboxylic acids (BPCAs) derived from pyrogenic carbon in environmental samples

Comprehensive radiocarbon analysis of benzene polycarboxylic acids (BPCAs) derived from pyrogenic carbon in environmental samples

Tephrochronology and its application: A review

Purification of fire derived markers for μg scale isotope analysis (δ13C, Δ14C) using high performance liquid chromatography (HPLC)

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