Fingerprinting ash deposits of small scale eruptions by their physical and textural features

Cioni, Raffaello; D’Oriano, Claudia; Bertagnini, A.

doi:10.1016/j.jvolgeores.2008.06.003

Cited by 55 publications

(60 citation statements)

References 34 publications

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“…Age data are useful in constraining the number of contenders for correlation or for distinguishing two tephras, for example those that are compositionally identical but which were erupted some hundreds to thousands of years apart (i.e., sufficiently separated in time so that high-precision ages obtained on both can probably enable them to be distinguished). At proximal locations, a range of physical and textural features can be used in addition to glass morphology and vesicularity to characterize tephras (e.g., Newton et al, 2007;Cioni et al, 2008). INAA, instrumental neutron activation analysis; SSMS, spark source mass spectrometry (now uncommon); SIMS, secondary ionization mass spectrometry (known also as ion probe/microprobe); SEM, scanning electron microscopy.…”

Section: Tephra Characterization and Correlation: Principlesmentioning

confidence: 99%

Tephrochronology and its application: A review

Lowe

2011

Quaternary Geochronology

635

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

635

535

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“…After a preliminary examination of all the samples, 5 specimens representative of activity at two different craters (SW and NE) on three different days were selected for detailed characterisation following the analytical procedure proposed by Cioni et al (2008). After sieving, about 30 juvenile fragments in the 0.5-1 mm size range were randomly hand-picked from each studied sample and then mounted with double-sided adhesive tape on a glass slide.…”

Section: Sampling and Methodsmentioning

confidence: 99%

“…At Stromboli, as for other volcanoes, the texture and composition of volcanic products closely reflect magmatic and eruptive processes (Taddeucci et al 2002;Cioni et al 2008;Houghton and Gonnermann 2008). The ability to systematically sample freshly erupted bombs is strongly controlled by the access to the summit during explosive activity.…”

Section: Introductionmentioning

confidence: 99%

Ash erupted during normal activity at Stromboli (Aeolian Islands, Italy) raises questions on how the feeding system works

2010

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Ash fallout collected during 4 days of sampling at Stromboli confirms that a crystal-rich (HP) degassed magma erupts during the Strombolian explosions that are characteristic of the normal activity of this volcano. We identified 3 different types of juvenile ash fragments (fluidal, spongy and dense), which formed through different mechanisms of fragmentation of the low-viscosity, physically heterogeneous (in terms of the size and spatial distribution of bubbles) shoshonitic magma. A small amount (less than 3 vol%) of volatile-rich magma with low porphyricity (LP), erupted as highly vesicular ash fragments, has been collected, together with the HP magma, during normal strombolian explosions. Laboratory experiments and the morphological, textural and compositional investigations of ash fragments reveal that the LP ash is fresh and not recycled from the last paroxysm (15 March 2007). We suggest that small droplets of LP magma are dragged to the surface by the time-variable but persistent supply of deep derived CO2-rich gas bubbles. This coupled ascent of bubbles and LP melts is transient and does not perturb the dynamics of the HP magma within the shallow reservoir. This finding provides a new perspective on how the Stromboli volcano works and has important implications for monitoring strategies

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“…It is probable that tephras were differentially distributed on the east and west side of the crater due to wind currents at the time of each tephra plume. It is also possible and likely for the tephra from a single eruption to vary in composition (e.g., Cioni et al, 2008). If the composition of Boquete area tephra varies too widely within the same eruption, however, it weakens or complicates the validity of the underlying assumption that mineralogical differences could provide a useful chronometric marker for Barú area archaeological sites.…”

Section: Correlating the Samplesmentioning

confidence: 99%

The cultural nature of tephra: ‘Problematic’ ecofacts and artifacts and the Barú volcano, Panamá

Holmberg

2016

Quaternary International

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a b s t r a c tThis paper presents data from archaeological stratigraphy and lacustrine core samples containing tephra from the Barú volcano in western Panama. The discussion seeks to refine the understanding of medial tephra deposits near Barú in relation to the eruption history indicated by geological, palaeoecological, and archaeological data. A primary goal of this fieldwork is the identification and correlation of tephra from major Barú eruptions encountered in archaeological contexts by their lithology, stratigraphic position, and mineralogy without resorting to geochemical fingerprinting. The intention is to develop a cost efficient and reproducible means of utilizing tephra as a chronostratigraphic marker in archaeological contexts and examine the intersection of human life with volcanic events and dynamic environments. Tephra in archaeological contexts can have ambiguous placement between ecofact and artifact, as is the case with a small number of crude tephra sculptures in my excavated material and that of a seminal prior study. While the research project utilizes visible tephra layers, not cryptotephra, by all means the tephra data prove to be cryptic. Engagement with the imperfection entailed in meshing multidisciplinary data sets and different scientific communities with interests in tephra, particularly in lesser studied regions, is posited as a 'total' view of tephra.

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Fingerprinting ash deposits of small scale eruptions by their physical and textural features

Cited by 55 publications

References 34 publications

Tephrochronology and its application: A review

Tephrochronology and its application: A review

Ash erupted during normal activity at Stromboli (Aeolian Islands, Italy) raises questions on how the feeding system works

The cultural nature of tephra: ‘Problematic’ ecofacts and artifacts and the Barú volcano, Panamá

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