Re‐identification of c. 15 700 cal yr BP tephra bed at Kaipo Bog, eastern North Island: Implications for dispersal of Rotorua and Puketarata tephra beds

Shane, Phil; Smith, Victoria; Lowe, David J.; Nairn, I. A.

doi:10.1080/00288306.2003.9515032

Cited by 29 publications

(20 citation statements)

References 16 publications

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“…This tephra is the product of an exceptionally large-volume eruption from TVC (Froggatt and Lowe, 1990;Wilson, 2001), dated at 26.5 ka. The 15.7 ka Rotorua tephra from OVC (Nairn, 2002) is found at 37.18 m at Onepoto and (Shane et al, 2003b). The dominant population has relatively high FeO and CaO contents compared to other OVC tephra, while the subordinant population is more evolved and displays a high K 2 O content (Fig.…”

Section: Chronologymentioning

confidence: 99%

Towards a comprehensive distal andesitic tephrostratigraphic framework for New Zealand based on eruptions from Egmont volcano

Shane

2005

J Quaternary Science

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Shane, P. 2005. Towards a comprehensive distal andesitic tephrostratigraphic framework for New Zealand based on eruptions from Egmont volcano.ABSTRACT: The chronology and glass composition of 43 andesitic tephra layers in palaeolake sediments in northern New Zealand provide the basis for a fine-resolution tephrostratigraphy of the interval 10-70 cal. ka. Their ages are constrained by 14 interbedded, (mostly) well-dated rhyolitic tephra layers. The andesitic tephra have the potential to subdivide time intervals (1-5 kyr) bracketed by well known rhyolitic layers, including periods of rapid climate change such as the last glacialinterglacial transition and the Younger Dryas. The source of the distal andesitic tephra is identified as Egmont volcano (some 270 km S-SW) on the basis of glass shard composition. The tephra contain high-K 2 O (3-6 wt%) andesitic-dacitic (SiO 2 ¼ 60-73 wt%) glass, with commonly heterogeneous shard populations (2-10 wt% SiO 2 ). Within stratigraphic intervals of < 10 kyr, individual tephra layers can be distinguished on the basis of their SiO 2 and K 2 O contents, and variability in these contents can also be a distinguishing characteristic. The tephra record greatly extends the dated pyroclastic and geochemical record of Egmont volcano, and demonstrates that the volcano has frequently produced widely dispersed tephra over the last 70 kyr at a generally constant rate.

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Section: Chronologymentioning

confidence: 99%

Towards a comprehensive distal andesitic tephrostratigraphic framework for New Zealand based on eruptions from Egmont volcano

Shane

2005

J Quaternary Science

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“…Eden et al, 2001;Shane and Hoverd, 2002;Newnham et al, 2003). Once determined, such compositional variations actually enhance the potential for correlation, by providing additional criteria to guide geochemical fingerprinting (Shane et al, 2003b).…”

Section: Characterising Tephrasmentioning

confidence: 99%

Tephrochronology of last termination sequences in Europe: a protocol for improved analytical precision and robust correlation procedures (a joint SCOTAV–INTIMATE proposal)

Turney¹,

Lowe

Davies

et al. 2004

J Quaternary Science

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115

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The precise sequence of events during the Last Termination (18 000-9000 ka 14 C yr BP), and the extent to which major environmental changes were synchronous, are difficult to establish using the radiocarbon method alone because of serious distortions of the radiocarbon time-scale, as well as the influences of site-specific errors that can affect the materials dated. Attention has therefore turned to other methods that can provide independent tests of the chronology and correlation of events during the Last Termination. With emphasis on European sequences, we summarise here the potential of tephrostratigraphy and tephrochronology to fulfil this role. Recent advances in the detection and analysis of 'hidden' tephra layers (cryptotephra) indicate that some tephras of Last Termination age are much more widespread in Europe than appreciated hitherto, and a number of new tephra deposits have also been identified. There is much potential for developing an integrated tephrochronological framework for Europe, which can help to underpin the overall chronology of events during the Last Termination. For that potential to be realised, however, there needs to be a more systematic and robust analysis of tephra layers than has been the practice in the past. We propose a protocol for improving analytical and reporting procedures, as well as the establishment of a centralised data base of the results, which will provide an important geochronological tool to support a diverse range of stratigraphical studies, including opportunities to reassess volcanic hazards. Although aimed primarily at Europe, the protocol proposed here is of equal relevance to other regions and periods of interest.

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“…15). These biotite differences provided the key to identifying one of the distal tephras in the Kaipo bog sequence in eastern North Island that previously had been misidentified because its major-element glass chemistry matched that of two eruptives identical in age but derived from different volcanic sources (Shane et al, 2003a(Shane et al, , 2003b Analyses of Fe-Ti oxides, titanomagnetite and ilmenite, by EPMA have been useful for tephra fingerprinting for many years (e.g., Westgate and Evans, 1978;Hogg and McCraw, 1983;Beaudoin and King, 1986;Julian et al, 1988;Cronin et al, 1996;Smith et al, 2002;McHenry, 2005;Turner et al, 2009). The validity of such analysis as a correlation tool was supported by crystal field theory (Hodder, 1981).…”

Section: In Favourable Circumstances Individual Tephras May Be Identmentioning

confidence: 99%

“…In defining and naming new tephras, or re-defining them, the usual rules of stratigraphic nomenclature apply but the need for care is emphasised and specialist guidance should be sought to avoid compounding any previous correlation errors or misnomers (Lowe, 1986a;Wilson, 1993;Shane et al, 2003a;Davies et al, 2004a;Westgate et al, 2008). In the first instance, applying unique "names" to new tephras (such as core number and depth of occurrence) is the optimum approach to reduce confusion and potential ambiguity if additional tephras are discovered during subsequent research (e.g., Bourne et al, in press).…”

Section: Defining and Using Type And Auxiliary Reference Locationsmentioning

confidence: 99%

Tephrochronology and its application: A review

Lowe

2011

Quaternary Geochronology

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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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Re‐identification of c. 15 700 cal yr BP tephra bed at Kaipo Bog, eastern North Island: Implications for dispersal of Rotorua and Puketarata tephra beds

Abstract: A 10 mm

Cited by 29 publications

References 16 publications

Towards a comprehensive distal andesitic tephrostratigraphic framework for New Zealand based on eruptions from Egmont volcano

Towards a comprehensive distal andesitic tephrostratigraphic framework for New Zealand based on eruptions from Egmont volcano

Tephrochronology of last termination sequences in Europe: a protocol for improved analytical precision and robust correlation procedures (a joint SCOTAV–INTIMATE proposal)

Tephrochronology and its application: A review

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