Geochemical characterization of Quaternary tephras from the Campanian Province, Italy

Turney, Chris S. M.; Blockley, Simon; Lowe, John J.; Wulf, Sabine; Branch, Nick; Mastrolorenzo, G.; Swindle, Gemma; Nathan, Roger; Pollard, A. Mark

doi:10.1016/j.quaint.2007.02.007

Cited by 35 publications

(26 citation statements)

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“…Where mineralogical and major-element data are unavailable, or prove insufficient or equivocal, then the next step is to obtain analyses on glass of trace and rare-earth elements (REEs) (Pearce et al, 2002(Pearce et al, , 2007Knott et al, 2007;Allan et al, 2008;Turney et al, 2008;Kuehn et al, 2009). A recent example of such a situation is that for the Sheep Creek group of tephras in western Canada and Alaska as described by Westgate et al (2008).…”

Section: Tephra Characterization and Correlation: Principlesmentioning

confidence: 99%

Tephrochronology and its application: A review

Lowe

2011

Quaternary Geochronology

638

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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Section: Tephra Characterization and Correlation: Principlesmentioning

confidence: 99%

Tephrochronology and its application: A review

Lowe

2011

Quaternary Geochronology

638

535

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“…Reanalysis of the geochemical characteristics of ash layers in the Mediterranean has shown that glass chemistry is often not unique to an eruption (Turney et al 2008;Smith et al 2011). Therefore other characteristics, for example the stratigraphy, chronology of the core and the magnitude of the eruption, are taken into account when assessing tephra provenance (Turney et al 2008;Smith et al 2011;Tomlinson et al 2012). Table 1 for further information).…”

Section: The Campanian Ignimbrite (Ci) Eruptionmentioning

confidence: 99%

Physical characteristics of tephra layers in the deep sea realm: the Campanian Ignimbrite eruption

Engwell

Sparks

Carey

2014

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Tephra deposits in the deep sea can survive undisturbed for long periods of time and, on regional scales, tend to be much better preserved than their subaerial counterparts. In this study, grain size distributions and thicknesses of tephra deposits from the Campanian Ignimbrite (CI) eruption (39 000 yr BP; magnitude c. 7.7) preserved in thirty-three deep sea cores are analysed to infer key eruption parameters. Distal deep sea tephra thickness data show an exponential decrease with distance from source. Such trends are difficult to identify in distal subaerial data owing to reworking and limited exposure. We find that tephra grain size distributions are much less affected by depositional environment than thickness, with trends that are consistent across distal subaerial, lacustrine and deep sea environments. The CI layer exhibits bimodal grain size distributions to distances of c. 1000 km, after which it becomes unimodal. Such trends can be related to different mechanisms of tephra transport in the atmosphere, whereby at proximal to medial distances the Plinian and co-ignimbrite phases produce distinct plumes. Within 150 and 900 km from source, Plinian tephra constitutes 40 + 5% of the deposit volume. Beyond this region where coarse particles are deposited, the plumes merge and fines derived largely from co-ignimbrite elutriation are spread in the atmosphere at velocities greater than the settling velocities of the particles.

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“…In the central and eastern Mediterranean, recognition of such tephra layers and their correlation to known eruptive events is an area of active research for improving the tephrostratigraphy of marine and lacustrine sequences in a mid-latitudinal region where the climatic signal is amplified by marked seasonal effects and a semi-closed oceanic circulation (Hilgen et al, 1993;Paterne et al, 2008;Wulf et al, 2004Wulf et al, , 2008Turney et al, 2008;Zanchetta et al, 2008;Aksu et al, 2008). While recent progress has been achieved in dating such tephras by 14 C bracketing (Siani et al, 2001(Siani et al, , 2004Lowe et al, 2007;Blockley et al, 2102), absolute age constraints remain relatively scarce for tephra beds lying beyond the reach of the radiocarbon timescale (Smith et al, 1996;van den Bogaard et al, 1999;Ton-That et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Millennial-scale phase relationships between ice-core and Mediterranean marine records: insights from high-precision 40Ar/39Ar dating of the Green Tuff of Pantelleria, Sicily Strait

Scaillet

Vita-Scaillet

Rotolo

2013

Quaternary Science Reviews

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International audienceWith the advent of annually-resolved polar ice records extending back to 70 ka, marine and continental paleoclimate studies have now matured into a discipline where high-quality age control is essential for putting on an equal pace layer-counted timescale models and Late Quaternary sedimentary records. High-resolution U-Th dating of speleothem records and 40Ar/39Ar dating of globally recorded geomagnetic excursions have recently improved the time calibration of Quaternary archives, reflecting the cross-disciplinary effort made to synchronize the geologic record at the millennial scale. Yet, tie-points with such an absolute age control remain scarce for paleoclimatic time-series extending beyond the radiocarbon timescale, most notably in the marine record. Far-travelled tephra layers recorded both onland and offshore provide an alternative in such instance to synchronize continental and marine archives via high-resolution 40Ar/39Ar dating of the parent volcanic eruption. High-resolution 40Ar/39Ar data are reported herein for one such volcanic marker, the Green Tuff of Pantelleria and its Y-6 tephra equivalent recorded throughout the Central and Eastern Mediterranean. Published radiochronometric and δ18O orbitally-tied ages for this marker horizon scatter widely from about 41 ka up to 56 ka. Our new 40Ar/39Ar age at 45.7 ± 1.0 ka (2σ) reveals that previous estimates are biased by more than their reported errors would suggest, including recent orbital tuning of marine records hosting the tephra bed that are reevaluated in the context of this study. This improved estimate enables potential phase lags and leads to be studied between deep-sea and terrestrial archives with unrivaled (near-millennial) 40Ar/39Ar precision in the marine record

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Geochemical characterization of Quaternary tephras from the Campanian Province, Italy

Cited by 35 publications

References 50 publications

Tephrochronology and its application: A review

Tephrochronology and its application: A review

Physical characteristics of tephra layers in the deep sea realm: the Campanian Ignimbrite eruption

Millennial-scale phase relationships between ice-core and Mediterranean marine records: insights from high-precision 40Ar/39Ar dating of the Green Tuff of Pantelleria, Sicily Strait

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