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Sabine Wulf - One of the best experts on this subject based on the ideXlab platform.
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the marine isotope stage 1 5 cryptoTephra record of tenaghi philippon greece towards a detailed tephrostratigraphic framework for the eastern mediterranean region
Quaternary Science Reviews, 2018Co-Authors: Simon P E Blockley, Sabine Wulf, Mark Hardiman, Richard A Staff, Andreas Koutsodendris, Oona Appelt, John J LoweAbstract:Abstract The iconic climate archive of Tenaghi Philippon (TP), NE Greece, allows the study of short-term palaeoclimatic and environmental change throughout the past 1.3 Ma. To provide high-quality age control for detailed palaeoclimate reconstructions based on the TP archive, (crypto)Tephra studies of a peat core ‘TP-2005’ have been carried out for the 0–130 ka interval. The results show that the TP basin is ideally positioned to receive Tephra fall from both the Italian and Aegean Arc volcanic provinces. Two visible Tephra layers, the Santorini Cape Riva/Y-2 (c. 22 ka) and the Campanian Ignimbrite (CI)/Y-5 (c. 39.8 ka) Tephras, and six primary cryptoTephra layers, namely the early Holocene E1 Tephra from the Aeolian Islands (c. 8.3 ka), the Campanian Y-3 (c. 29 ka) and X-6 Tephras (c. 109.5 ka), as well as counterpart Tephras TM-18-1d (c. 40.4 ka), TM-23-11 (c. 92.4 ka) and TM-33-1a (c. 116.7 ka) from the Lago Grande di Monticchio sequence (southern Italy), were identified along with repeatedly redeposited Y-2 and CI Tephra material. Bayesian modelling of the ages of seven of the primary Tephra layers, 60 radiocarbon measurements and 20 palynological control points have been applied to markedly improve the chronology of the TP archive. This revised chronology constrains the age of Tephra TM-18-1d to 40.90–41.66 cal ka BP (95.4% range). Several Tephra layers identified in the TP record form important isochrons for correlating this archive with other terrestrial (e.g., Lago Grande di Monticchio, Sulmona Basin and Lake Ohrid) and marine (e.g., Adriatic Sea core PRAD 1-2 and Aegean Sea core LC21) palaeoclimate records in the Mediterranean region.
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constraining the time span between the early holocene hasseldalen and askja s Tephras through varve counting in the lake czechowskie sediment record poland
Journal of Quaternary Science, 2016Co-Authors: Florian Ott, Sabine Wulf, Johanna Serb, Michal Slowinski, Milena Obremska, Rik Tjallingii, Miroslaw Blaszkiewicz, Achim BrauerAbstract:We report the first findings of coexisting early Holocene Hasseldalen and Askja-S cryptoTephras in a varved sediment record in Lake Czechowskie (Poland). A time span of 152 +11/−8 varve years between the two Tephras has been revealed by differential dating through varve counting. This is in agreement within the uncertainties with calculations from radiocarbon-based age models from the non-varved Hasseldala port record in southern Sweden, but shorter than assumed from the non-varved lake record on the Faroe Islands. We discuss possible reasons for the observed differences in duration between the two Tephras and provide a revised absolute age for the Askja-S Tephra of 11 228 ± 226 cal a BP based on anchoring our floating varve chronology to the absolute timescale by using the Hasseldalen Tephra as dated in the Hasseldala port sediments (11 380 ± 216 cal a BP). This age agrees with radiocarbon age models with larger uncertainty ranges, but is slightly older than radiocarbon-based age models with narrow uncertainty bands and is even 200–300 years older than the age reported from the Faroe Islands record. In addition to these chronological issues we discuss the possible response of the Czechowskie sediment record to the Preboreal climate oscillation.
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a new contribution to the late quaternary tephrostratigraphy of the mediterranean aegean sea core lc21
Quaternary Science Reviews, 2015Co-Authors: Christopher Satow, Sabine Wulf, Emma L Tomlinson, Katherine Grant, Paul G Albert, Victoria C Smith, Christina Manning, Luisa Ottolini, Elco RohlingAbstract:Tephra layers preserved in marine sediments can contribute to the reconstruction of volcanic histories and potentially act as stratigraphic isochrons to link together environmental records. Recent de- velopments in the detection of volcanic ash (Tephra) at levels where none is macroscopically visible (so- called 'crypto-Tephra') have greatly enhanced the potential of tephrostratigraphy for synchronising environmental and archaeological records by expanding the areas over which Tephras are found. In this paper, crypto-Tephra extraction techniques allow the recovery of 8 non-visible Tephra layers to add to the 9 visible layers in a marine sediment core (LC21) from the SE Aegean Sea to form the longest, single core record of volcanic activity in the Aegean Sea. Using a novel, shard-specific methodology, sources of the Tephra shards are identified on the basis of their major and trace element single-shard geochemistry, by comparison with geochemical data from proximal Mediterranean volcanic stratigraphies. The results indicate that the Tephra layers are derived from 14 or 15 separate eruptions in the last ca 161 ka BP: 9 from Santorini; 2 or 3 from Kos, Yali, or Nisyros; 2 from the Campanian province; and one from Pan- telleria. The attributions of these Tephra layers indicate that 1) inter-Plinian eruptions from Santorini may have produced regionally significant Tephra deposits, 2) marine tephrostratigraphies can provide unique and invaluable data to eruptive histories for island volcanoes, and 3) Tephra from both Pantelleria and Campania may be used to correlate marine records from the Aegean Sea to those from the Tyrrhenian, Adriatic and Ionian Seas.
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tephrochronology of core prad 1 2 from the adriatic sea insights into italian explosive volcanism for the period 200 80 ka
Quaternary Science Reviews, 2015Co-Authors: A J Bourne, Simon P E Blockley, Sabine Wulf, Paul G Albert, Jorg Keller, Ian Matthews, Fabio Trincardi, Alessandra Asioli, John J LoweAbstract:Core PRAD 1-2, located on the western flank of the Mid-Adriatic Deep, was investigated for Tephra content within the part of the sequence assigned on biostratigraphic and sapropel-layer stratigraphy to MIS 5 and 6 (ca. 80–200 ka BP). A total of 11 discrete Tephra layers are identified, 8 visible and 3 cryptoTephra layers. 235 geochemical measurements obtained from individual glass shards using WDS-EPMA enabled 8 of the 11 Tephras to be correlated to known eruption events, 5 of which are represented in the Lago Grande di Monticchio (LGdM) regional Tephra archive sequence. Three of these layers are recognised ultra-distally for the first time, extending their known distributions approximately 210 km further north. The results provide an independent basis for establishing an age-depth profile for the MIS 5–6 interval in the PRAD 1-2 marine record. This approach allowed age estimates to be interpolated for the Tephra layers that could not be correlated to known events. It also provides an independent test of, and support for, the broad synchroneity of sapropel-equivalent (S-E) events in the Adriatic Sea with the better-developed sapropel layers of the eastern Mediterranean, proposed by Piva et al. (2008a).
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the 100 133 ka record of italian explosive volcanism and revised tephrochronology of lago grande di monticchio
Quaternary Science Reviews, 2012Co-Authors: Sabine Wulf, Paul G Albert, Jorg Keller, Martine Paterne, Jens Mingram, Stefan Lauterbach, Stephan Opitz, Gianluca Sottili, Biagio Giaccio, Christopher SatowAbstract:Laminated sediments of the maar lake Lago Grande di Monticchio in southern Italy exhibit a unique sequence of numerous primary Tephra events that provide both insights into the Late Quaternary eruptive history of Italian volcanoes and an archive of essential marker horizons for dating and linking palaeoclimate records throughout the Central and Eastern Mediterranean. The acquisition of new sediment cores from this lake now extends the existing 100 ka-Tephra record back to 133 ka BP, the end of the penultimate Glacial. The additional ca 30 m of sediments host a total number of 52 single Tephra layers forming 21 Tephra clusters that have been characterised on the basis of detailed geochemical and petrographical examinations. Tephras can be assigned to hitherto poorly known Plinian to sub-Plinian eruptive events of the nearby Campanian (Ischia Island, Phlegrean Fields), Roman (Sabatini volcanic district) and Aeolian-Sicilian volcanoes (Etna, Stromboli, Salina) and are dated according to the varve and sedimentation rate chronology of Monticchio sediments. The most prominent Tephra layers within the interval of investigation – TM-25 and TM-27 – can be firmly correlated with Ionian Sea Tephras X-5 (ca 105 ka BP) and X-6 (ca 108–110 ka BP). In addition, a further 26 Tephra layers are correlated with radiometrically and radioisotopically dated volcanic events providing the basis for a robust revised tephrochronology of the entire Monticchio sediment sequence for the last 133 ka.
Simon P E Blockley - One of the best experts on this subject based on the ideXlab platform.
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the marine isotope stage 1 5 cryptoTephra record of tenaghi philippon greece towards a detailed tephrostratigraphic framework for the eastern mediterranean region
Quaternary Science Reviews, 2018Co-Authors: Simon P E Blockley, Sabine Wulf, Mark Hardiman, Richard A Staff, Andreas Koutsodendris, Oona Appelt, John J LoweAbstract:Abstract The iconic climate archive of Tenaghi Philippon (TP), NE Greece, allows the study of short-term palaeoclimatic and environmental change throughout the past 1.3 Ma. To provide high-quality age control for detailed palaeoclimate reconstructions based on the TP archive, (crypto)Tephra studies of a peat core ‘TP-2005’ have been carried out for the 0–130 ka interval. The results show that the TP basin is ideally positioned to receive Tephra fall from both the Italian and Aegean Arc volcanic provinces. Two visible Tephra layers, the Santorini Cape Riva/Y-2 (c. 22 ka) and the Campanian Ignimbrite (CI)/Y-5 (c. 39.8 ka) Tephras, and six primary cryptoTephra layers, namely the early Holocene E1 Tephra from the Aeolian Islands (c. 8.3 ka), the Campanian Y-3 (c. 29 ka) and X-6 Tephras (c. 109.5 ka), as well as counterpart Tephras TM-18-1d (c. 40.4 ka), TM-23-11 (c. 92.4 ka) and TM-33-1a (c. 116.7 ka) from the Lago Grande di Monticchio sequence (southern Italy), were identified along with repeatedly redeposited Y-2 and CI Tephra material. Bayesian modelling of the ages of seven of the primary Tephra layers, 60 radiocarbon measurements and 20 palynological control points have been applied to markedly improve the chronology of the TP archive. This revised chronology constrains the age of Tephra TM-18-1d to 40.90–41.66 cal ka BP (95.4% range). Several Tephra layers identified in the TP record form important isochrons for correlating this archive with other terrestrial (e.g., Lago Grande di Monticchio, Sulmona Basin and Lake Ohrid) and marine (e.g., Adriatic Sea core PRAD 1-2 and Aegean Sea core LC21) palaeoclimate records in the Mediterranean region.
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tephrochronology of core prad 1 2 from the adriatic sea insights into italian explosive volcanism for the period 200 80 ka
Quaternary Science Reviews, 2015Co-Authors: A J Bourne, Simon P E Blockley, Sabine Wulf, Paul G Albert, Jorg Keller, Ian Matthews, Fabio Trincardi, Alessandra Asioli, John J LoweAbstract:Core PRAD 1-2, located on the western flank of the Mid-Adriatic Deep, was investigated for Tephra content within the part of the sequence assigned on biostratigraphic and sapropel-layer stratigraphy to MIS 5 and 6 (ca. 80–200 ka BP). A total of 11 discrete Tephra layers are identified, 8 visible and 3 cryptoTephra layers. 235 geochemical measurements obtained from individual glass shards using WDS-EPMA enabled 8 of the 11 Tephras to be correlated to known eruption events, 5 of which are represented in the Lago Grande di Monticchio (LGdM) regional Tephra archive sequence. Three of these layers are recognised ultra-distally for the first time, extending their known distributions approximately 210 km further north. The results provide an independent basis for establishing an age-depth profile for the MIS 5–6 interval in the PRAD 1-2 marine record. This approach allowed age estimates to be interpolated for the Tephra layers that could not be correlated to known events. It also provides an independent test of, and support for, the broad synchroneity of sapropel-equivalent (S-E) events in the Adriatic Sea with the better-developed sapropel layers of the eastern Mediterranean, proposed by Piva et al. (2008a).
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identification and correlation of visible Tephras in the lake suigetsu sg06 sedimentary archive japan chronostratigraphic markers for synchronising of east asian west pacific palaeoclimatic records across the last 150 ka
Quaternary Science Reviews, 2013Co-Authors: Victoria C Smith, Simon P E Blockley, Richard A Staff, Christopher Bronk Ramsey, Takeshi Nakagawa, Darren F Mark, Keiji Takemura, Toru DanharaAbstract:Abstract The Lake Suigetsu SG06 sedimentary archive from Honshu Island, central Japan, provides a high-resolution palaeoenvironmental record, including a detailed record of explosive volcanism from Japan and South Korea. Thirty visible Tephra are recorded within the 73 m-long SG06 core, which spans the last ∼150 ka. Here we describe and characterise these Tephras based on major element glass composition, which is useful for the identification and correlation of these Tephras and the age models of the records in which they are found. Utilising the large number of radiocarbon measurements ( n > 600) from terrestrial plant macrofossils in the Lake Suigetsu SG06 record, we are able to provide precise and accurate ages for the Tephras from eruptions within the last 50 ka. Glass compositional data of some of the largest eruptions from Japan (K-Ah, AT, Aso-4, Aso-A, Aso-D, and Ata; sampled at proximal outcrops) are also presented. These data show that the major element glass chemistry is distinctive for many of the visible SG06 Tephra units, and allows some of the layers to be correlated to known eruptions from volcanoes in Japan and South Korea, namely K-Ah (SG06-0967), U-Oki (SG06-1288), AT (SG06-2650), Aso-4 (SG06-4963/SG06-4979), K-Tz (SG06-5181), Aso-ABCD (SG06-5287) and Ata (SG06-5181). The following ages were obtained for the SG06 Tephra units: 3.966–4.064 cal. ka BP (95.4% probability range) for the SG06-0588 Tephra, 10.242–10.329 cal. ka BP (95.4% probability range) for SG06-1293, 19.487 ± 112 SG06 2012 ka BP (2 σ ) for SG06-1965, 28.425 ± 194 SG06 2012 ka BP (2 σ ) for SG06-2504, 28.848 ± 196 SG06 2012 ka BP (2 σ ) for SG06-2534, 29.765 ± 190 SG06 2012 ka BP (2 σ ) for SG06-2601, 29.775 ± 191 SG06 2012 ka BP (2 σ ) for SG06-2602, 43.713 ± 156 SG06 2012 ka BP (2 σ ) for SG06-3485, 46.364 ± 202 SG06 2012 ka BP (2 σ ) for SG06-3668, 49.974 ± 337 SG06 2012 ka BP (2 σ ) for SG06-3912, 50.929 ± 378 SG06 2012 ka BP (2 σ ) for SG06-3974, and improved ages for two of the most important Tephra markers across Japan, the K-Ah (7.165–7.303 cal. ka BP at 95.4% probability range; SG06-0967) and AT Tephra (30.009 ± 189 SG06 2012 ka BP at 2 σ ; SG06-2650).
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distal Tephra record for the last ca 105 000 years from core prad 1 2 in the central adriatic sea implications for marine tephrostratigraphy
Quaternary Science Reviews, 2010Co-Authors: A J Bourne, Simon P E Blockley, Sabine Wulf, John J Lowe, Ian Matthews, Fabio Trincardi, Alessandra Asioli, Andrea Piva, Luigi VigliottiAbstract:Abstract Core PRAD 1-2, located on the western flank of the Mid-Adriatic Deep, contains a continuous sediment record extending back to upper MIS-11. The upper part of the record which spans the mid Holocene to MIS 5–4 (the last ca 105,000 years) has been investigated for Tephra content. A total of 25 discrete Tephra layers were discovered, only one of which was visible in the core sequence. The other 24 are not visible to the naked eye, nor were the majority detected by routine down-core scanning methods. A total of 625 geochemical measurements obtained from individual glass shards using WDS-EPMA enabled 21 of the 25 Tephras to be assigned to known volcanic events emanating from the Campanian Province (Campi Flegrei, Somma-Vesuvius and Ischia Island). The results provide an independent basis for establishing an age–depth profile for the upper part of the PRAD 1-2 record. This study demonstrates that the number of non-visible Tephra layers can significantly exceed the number of visible layers in some deep marine sequences. Routine testing for the presence of non-visible Tephra layers can therefore prove rewarding, leading to the detection of additional isochrons for dating and correlating marine sequences, and for their synchronisation with terrestrial records.
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distal volcanic ash layers in the lateglacial interstadial gi 1 problems of stratigraphic discrimination
Quaternary Science Reviews, 2008Co-Authors: Sean Pyneodonnell, Simon P E Blockley, Chris S M TurneyAbstract:Abstract A new Icelandic ash layer has been detected in mid-Interstadial sediments in a number of Scottish Lateglacial sequences and has been named the Penifiler Tephra. It is rhyolitic in composition and possesses a chemistry, which is similar to the Borrobol Tephra of early Lateglacial Interstadial age, which also occurs in a number of these same sequences. Where the Borrobol Tephra has been identified in these sequences it consistently exhibits a diffuse distribution accompanied in some cases by stratigraphic bimodality. A number of sedimentological and taphonomic factors are considered in order to account for this distribution. One possibility is that these distributions are produced by taphonomic factors. Another possibility is that the Borrobol Tephra may not be the product of a single Icelandic eruption, but of two events closely spaced in time. In at least two of the sequences investigated in this study, basaltic shards were found in association with the Penifiler and Borrobol Tephras, suggesting either a basaltic phase associated with these eruptions, or coincident eruptions from a separate basaltic volcanic centre. The discovery of the new Penifiler Tephra makes a contribution to the regional tephrostratigraphic framework, and provides an additional isochron for assessing the synchroneity of palaeoenvironmental changes during the Interstadial. The true stratigraphic nature and age of the Borrobol Tephra, however, remains unresolved and, therefore, its use as an isochron is more problematic. The possible occurrence of basaltic populations may strengthen correlations with basaltic Tephras recently detected in the NGRIP ice-core.
John J Lowe - One of the best experts on this subject based on the ideXlab platform.
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the marine isotope stage 1 5 cryptoTephra record of tenaghi philippon greece towards a detailed tephrostratigraphic framework for the eastern mediterranean region
Quaternary Science Reviews, 2018Co-Authors: Simon P E Blockley, Sabine Wulf, Mark Hardiman, Richard A Staff, Andreas Koutsodendris, Oona Appelt, John J LoweAbstract:Abstract The iconic climate archive of Tenaghi Philippon (TP), NE Greece, allows the study of short-term palaeoclimatic and environmental change throughout the past 1.3 Ma. To provide high-quality age control for detailed palaeoclimate reconstructions based on the TP archive, (crypto)Tephra studies of a peat core ‘TP-2005’ have been carried out for the 0–130 ka interval. The results show that the TP basin is ideally positioned to receive Tephra fall from both the Italian and Aegean Arc volcanic provinces. Two visible Tephra layers, the Santorini Cape Riva/Y-2 (c. 22 ka) and the Campanian Ignimbrite (CI)/Y-5 (c. 39.8 ka) Tephras, and six primary cryptoTephra layers, namely the early Holocene E1 Tephra from the Aeolian Islands (c. 8.3 ka), the Campanian Y-3 (c. 29 ka) and X-6 Tephras (c. 109.5 ka), as well as counterpart Tephras TM-18-1d (c. 40.4 ka), TM-23-11 (c. 92.4 ka) and TM-33-1a (c. 116.7 ka) from the Lago Grande di Monticchio sequence (southern Italy), were identified along with repeatedly redeposited Y-2 and CI Tephra material. Bayesian modelling of the ages of seven of the primary Tephra layers, 60 radiocarbon measurements and 20 palynological control points have been applied to markedly improve the chronology of the TP archive. This revised chronology constrains the age of Tephra TM-18-1d to 40.90–41.66 cal ka BP (95.4% range). Several Tephra layers identified in the TP record form important isochrons for correlating this archive with other terrestrial (e.g., Lago Grande di Monticchio, Sulmona Basin and Lake Ohrid) and marine (e.g., Adriatic Sea core PRAD 1-2 and Aegean Sea core LC21) palaeoclimate records in the Mediterranean region.
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tephrochronology of core prad 1 2 from the adriatic sea insights into italian explosive volcanism for the period 200 80 ka
Quaternary Science Reviews, 2015Co-Authors: A J Bourne, Simon P E Blockley, Sabine Wulf, Paul G Albert, Jorg Keller, Ian Matthews, Fabio Trincardi, Alessandra Asioli, John J LoweAbstract:Core PRAD 1-2, located on the western flank of the Mid-Adriatic Deep, was investigated for Tephra content within the part of the sequence assigned on biostratigraphic and sapropel-layer stratigraphy to MIS 5 and 6 (ca. 80–200 ka BP). A total of 11 discrete Tephra layers are identified, 8 visible and 3 cryptoTephra layers. 235 geochemical measurements obtained from individual glass shards using WDS-EPMA enabled 8 of the 11 Tephras to be correlated to known eruption events, 5 of which are represented in the Lago Grande di Monticchio (LGdM) regional Tephra archive sequence. Three of these layers are recognised ultra-distally for the first time, extending their known distributions approximately 210 km further north. The results provide an independent basis for establishing an age-depth profile for the MIS 5–6 interval in the PRAD 1-2 marine record. This approach allowed age estimates to be interpolated for the Tephra layers that could not be correlated to known events. It also provides an independent test of, and support for, the broad synchroneity of sapropel-equivalent (S-E) events in the Adriatic Sea with the better-developed sapropel layers of the eastern Mediterranean, proposed by Piva et al. (2008a).
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distal Tephra record for the last ca 105 000 years from core prad 1 2 in the central adriatic sea implications for marine tephrostratigraphy
Quaternary Science Reviews, 2010Co-Authors: A J Bourne, Simon P E Blockley, Sabine Wulf, John J Lowe, Ian Matthews, Fabio Trincardi, Alessandra Asioli, Andrea Piva, Luigi VigliottiAbstract:Abstract Core PRAD 1-2, located on the western flank of the Mid-Adriatic Deep, contains a continuous sediment record extending back to upper MIS-11. The upper part of the record which spans the mid Holocene to MIS 5–4 (the last ca 105,000 years) has been investigated for Tephra content. A total of 25 discrete Tephra layers were discovered, only one of which was visible in the core sequence. The other 24 are not visible to the naked eye, nor were the majority detected by routine down-core scanning methods. A total of 625 geochemical measurements obtained from individual glass shards using WDS-EPMA enabled 21 of the 25 Tephras to be assigned to known volcanic events emanating from the Campanian Province (Campi Flegrei, Somma-Vesuvius and Ischia Island). The results provide an independent basis for establishing an age–depth profile for the upper part of the PRAD 1-2 record. This study demonstrates that the number of non-visible Tephra layers can significantly exceed the number of visible layers in some deep marine sequences. Routine testing for the presence of non-visible Tephra layers can therefore prove rewarding, leading to the detection of additional isochrons for dating and correlating marine sequences, and for their synchronisation with terrestrial records.
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a new and less destructive laboratory procedure for the physical separation of distal glass Tephra shards from sediments
Quaternary Science Reviews, 2005Co-Authors: A. M. Pollard, Sean Pyneodonnell, Chris S M Turney, Simon P E Blockley, John J Lowe, Ian Matthews, A Stone, Elizabeth MolyneuxAbstract:Abstract Tephrochronology, a key tool in the correlation of Quaternary sequences, relies on the extraction of Tephra shards from sediments for visual identification and high-precision geochemical comparison. A prerequisite for the reliable correlation of Tephra layers is that the geochemical composition of glass shards remains unaltered by natural processes (e.g. chemical exchange in the sedimentary environment) and/or by laboratory analytical procedures. However, natural glasses, particularly when in the form of small shards with a high surface to volume ratio, are prone to chemical alteration in both acidic and basic environments. Current techniques for the extraction of distal Tephra from sediments involve the ‘cleaning’ of samples in precisely such environments and at elevated temperatures. The acid phase of the ‘cleaning’ process risks alteration of the geochemical signature of the shards, while the basic phase leads to considerable sample loss through dissolution of the silica network. Here, we illustrate the degree of alteration and loss to which distal Tephras may be prone, and introduce a less destructive procedure for their extraction. This method is based on stepped heavy liquid flotation and which results in samples of sufficient quality for analysis while preserving their geochemical integrity. In trials, this method out-performed chemical extraction procedures in terms of the number of shards recovered and has resulted in the detection of new Tephra layers with low shard concentrations. The implications of this study are highly significant because (i) the current database of distal Tephra records and their corresponding geochemical signatures may require refinement and (ii) the record of distal Tephras may be incomplete due to sample loss induced by corrosive laboratory procedures. It is therefore vital that less corrosive laboratory procedures are developed to make the detection and classification of distal glass Tephra more secure.
Roland Maas - One of the best experts on this subject based on the ideXlab platform.
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final magma storage depth modulation of explosivity and trachyte phonolite genesis at an intraplate volcano a case study from ulleung island south korea
Journal of Petrology, 2014Co-Authors: Marco Brenna, Richard C Price, Shane J Cronin, Ian E M Smith, Young Kwan Sohn, Gi Bom Kim, Roland MaasAbstract:Ulleung Island is the top of a 3000 m (from sea floor) intraplate alkalic volcanic edifice in the East Sea/Sea of Japan. The emergent 950 m consist of a basaltic lava and agglomerate succession (Stage 1, 1·37^0·97Ma), intruded and overlain by a sequence of trachytic lavas and domes, which erupted in two episodes (Stage 2, 0·83^ 0·77Ma; Stage 3, 0·73^0·24Ma). The youngest eruptions, post 20 ka BP, were explosive, generating thick Tephra sequences of phonolitic composition (Stage 4), which also entrained phaneritic, porphyritic and cumulate accidental lithics. Major element chemistry of the evolved products shows a continuous spectrum of trachyte to phonolite compositions, but these have discordant trace element trends and distinct isotopic characteristics, excluding a direct genetic relationship between the two end-members. Despite this, the Stage 3 trachytes and some porphyritic accidental lithics have chemical characteristics transitional between Stage 2 trachytes and Stage 4 phonolites. Within the phonolitic Stage 4 Tephras three subgroups can be distinguished. The oldest, Tephra 5, is considerably enriched in incompatible elements and chondrite-normalized rare earth element (REE) patterns display negative Eu anomalies.The later Tephras, Tephras 4^2, have compositions intermediate between the early units and the trachyte samples, and their REE patterns do not have significant Eu anomalies.The last erupted,Tephra 1, from a small intra-caldera structure, has a distinct tephriphonolite composition. Trace element and isotopic chemistry as well as textural characteristics suggest a genetic relationship between the phaneritic lithics and their host phonolitic pumices.The Stage 4 Tephras are not related to earlier phases of basaltic to trachytic magmatism (Stages 1^3). They have distinct isotopic compositions and cannot be reliably modelled by fractional crystallization processes.The differences between the explosive phonolitic (Stage 4) and effusive trachytic (Stage 2^ 3) eruptions are mainly due to different pre-eruptive pressures and temperatures, causing closedversus open-system degassing. Based on thermodynamic and thermobarometric modelling, the phonolites were derived from deeper (subcrustal) magma storage and rose quickly, with volatiles trapped until eruption. By contrast, the trachytes were stored at shallower crustal levels for longer periods, allowing open-system volatile exsolution and degassing before eruption.
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final magma storage depth modulation of explosivity and trachyte phonolite genesis at an intraplate volcano a case study from ulleung island south korea
Journal of Petrology, 2014Co-Authors: Marco Brenna, Richard C Price, Shane J Cronin, Ian E M Smith, Young Kwan Sohn, Gi Bom Kim, Roland MaasAbstract:Ulleung Island is the top of a 3000 m (from sea floor) intraplate alkalic volcanic edifice in the East Sea/Sea of Japan. The emergent 950 m consist of a basaltic lava and agglomerate succession (Stage 1, 137-097Ma), intruded and overlain by a sequence of trachytic lavas and domes, which erupted in two episodes (Stage 2, 083-077Ma; Stage 3, 073-024Ma). The youngest eruptions, post 20 ka BP, were explosive, generating thick Tephra sequences of phonolitic composition (Stage 4), which also entrained phaneritic, porphyritic and cumulate accidental lithics. Major element chemistry of the evolved products shows a continuous spectrum of trachyte to phonolite compositions, but these have discordant trace element trends and distinct isotopic characteristics, excluding a direct genetic relationship between the two end-members. Despite this, the Stage 3 trachytes and some porphyritic accidental lithics have chemical characteristics transitional between Stage 2 trachytes and Stage 4 phonolites. Within the phonolitic Stage 4 Tephras three subgroups can be distinguished. The oldest,Tephra 5, is considerably enriched in incompatible elements and chondrite-normalized rare earth element (REE) patterns display negative Eu anomalies.The later Tephras, Tephras 4-2, have compositions intermediate between the early units and the trachyte samples, and their REE patterns do not have significant Eu anomalies.The last erupted,Tephra 1, from a small intra-caldera structure, has a distinct tephriphonolite composition. Trace element and isotopic chemistry as well as textural characteristics suggest a genetic relationship between the phaneritic lithics and their host phonolitic pumices.The Stage 4 Tephras are not related to earlier phases of basaltic to trachytic magmatism (Stages 1-3). They have distinct isotopic compositions and cannot be reliably modelled by fractional crystallization processes.The differences between the explosive phonolitic (Stage 4) and effusive trachytic (Stage 2-3) eruptions are mainly due to different pre-eruptive pressures and temperatures, causing closed-versus open-system degassing. Based on thermodynamic and thermobarometric modelling, the phonolites were derived from deeper (subcrustal) magma storage and rose quickly, with volatiles trapped until eruption. By contrast, the trachytes were stored at shallower crustal levels for longer periods, allowing open-system volatile exsolution and degassing before eruption. © The Author 2014. Published by Oxford University Press. All rights reserved.
Paul G Albert - One of the best experts on this subject based on the ideXlab platform.
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the major and trace element glass compositions of the productive mediterranean volcanic sources tools for correlating distal Tephra layers in and around europe
Quaternary Science Reviews, 2015Co-Authors: Emma L Tomlinson, Paul G Albert, Victoria C Smith, Erkan Aydar, L Civetta, Raffaello Cioni, Evren Cubukcu, Ralf Gertisser, Roberto Isaia, Martin MenziesAbstract:Abstract The increasing application of cryptoTephra studies is leading the identification of new Tephra marker layers the sources of which in many cases may not be known or may be ambiguous. In this contribution, we discuss the controls on Tephra geochemistry in the context of establishing the provenance of an unknown Tephra layer. We use the RESET database ( https://c14.arch.ox.ac.uk ), which contains major and trace element data for a number of European silicic Tephra erupted in the period 100 ka to ca 10 ka, to define new and modify existing tectonic setting discrimination diagrams for use with volcanic glass analyses. Bivariate plots of the elements Rb, Nb, Ta, Y and Th and K 2 O, SiO 2 , FeO and MgO can be used to identify Tephra from different tectonic settings. New, detailed glass chemistry shows that Tephra from the productive Neapolitan volcanic centres, Somma-Vesuvius (22–4 ka activity), Campi Flegrei (60–15 ka) and Ischia (75–20 ka), can be separated using major elements, CaO–SiO 2 , Na 2 O/K 2 O–CaO and CaO–MgO. In each of these centres, the tephrostratigraphic record is characterized by the repeated occurrence of similar glass compositions, punctuated by significant changes in magma chemistry. The glass compositions of successive eruptions from Campi Flegrei are similar but there is a significant change in the composition following the Campanian Ignimbrite, and there are comparable compositional changes at Ischia following the Monte Epomeo Green Tuff eruption and at Somma-Vesuvius following the Verdoline event. Distinguishing different Tephras from a single volcanic centre is more problematic, and in some instances even impossible, without good chronological and stratigraphic control and/or high-resolution trace element glass data. At Somma-Vesuvius certain major elements can be used to separate glasses from the major chronological phases (Group 1 – Pomici di Base and Verdoline; Group 2 – Mercato and Avellino), but separating Tephras within a single group on the basis of glass composition can be problematic.
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a new contribution to the late quaternary tephrostratigraphy of the mediterranean aegean sea core lc21
Quaternary Science Reviews, 2015Co-Authors: Christopher Satow, Sabine Wulf, Emma L Tomlinson, Katherine Grant, Paul G Albert, Victoria C Smith, Christina Manning, Luisa Ottolini, Elco RohlingAbstract:Tephra layers preserved in marine sediments can contribute to the reconstruction of volcanic histories and potentially act as stratigraphic isochrons to link together environmental records. Recent de- velopments in the detection of volcanic ash (Tephra) at levels where none is macroscopically visible (so- called 'crypto-Tephra') have greatly enhanced the potential of tephrostratigraphy for synchronising environmental and archaeological records by expanding the areas over which Tephras are found. In this paper, crypto-Tephra extraction techniques allow the recovery of 8 non-visible Tephra layers to add to the 9 visible layers in a marine sediment core (LC21) from the SE Aegean Sea to form the longest, single core record of volcanic activity in the Aegean Sea. Using a novel, shard-specific methodology, sources of the Tephra shards are identified on the basis of their major and trace element single-shard geochemistry, by comparison with geochemical data from proximal Mediterranean volcanic stratigraphies. The results indicate that the Tephra layers are derived from 14 or 15 separate eruptions in the last ca 161 ka BP: 9 from Santorini; 2 or 3 from Kos, Yali, or Nisyros; 2 from the Campanian province; and one from Pan- telleria. The attributions of these Tephra layers indicate that 1) inter-Plinian eruptions from Santorini may have produced regionally significant Tephra deposits, 2) marine tephrostratigraphies can provide unique and invaluable data to eruptive histories for island volcanoes, and 3) Tephra from both Pantelleria and Campania may be used to correlate marine records from the Aegean Sea to those from the Tyrrhenian, Adriatic and Ionian Seas.
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tephrochronology of core prad 1 2 from the adriatic sea insights into italian explosive volcanism for the period 200 80 ka
Quaternary Science Reviews, 2015Co-Authors: A J Bourne, Simon P E Blockley, Sabine Wulf, Paul G Albert, Jorg Keller, Ian Matthews, Fabio Trincardi, Alessandra Asioli, John J LoweAbstract:Core PRAD 1-2, located on the western flank of the Mid-Adriatic Deep, was investigated for Tephra content within the part of the sequence assigned on biostratigraphic and sapropel-layer stratigraphy to MIS 5 and 6 (ca. 80–200 ka BP). A total of 11 discrete Tephra layers are identified, 8 visible and 3 cryptoTephra layers. 235 geochemical measurements obtained from individual glass shards using WDS-EPMA enabled 8 of the 11 Tephras to be correlated to known eruption events, 5 of which are represented in the Lago Grande di Monticchio (LGdM) regional Tephra archive sequence. Three of these layers are recognised ultra-distally for the first time, extending their known distributions approximately 210 km further north. The results provide an independent basis for establishing an age-depth profile for the MIS 5–6 interval in the PRAD 1-2 marine record. This approach allowed age estimates to be interpolated for the Tephra layers that could not be correlated to known events. It also provides an independent test of, and support for, the broad synchroneity of sapropel-equivalent (S-E) events in the Adriatic Sea with the better-developed sapropel layers of the eastern Mediterranean, proposed by Piva et al. (2008a).
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the 100 133 ka record of italian explosive volcanism and revised tephrochronology of lago grande di monticchio
Quaternary Science Reviews, 2012Co-Authors: Sabine Wulf, Paul G Albert, Jorg Keller, Martine Paterne, Jens Mingram, Stefan Lauterbach, Stephan Opitz, Gianluca Sottili, Biagio Giaccio, Christopher SatowAbstract:Laminated sediments of the maar lake Lago Grande di Monticchio in southern Italy exhibit a unique sequence of numerous primary Tephra events that provide both insights into the Late Quaternary eruptive history of Italian volcanoes and an archive of essential marker horizons for dating and linking palaeoclimate records throughout the Central and Eastern Mediterranean. The acquisition of new sediment cores from this lake now extends the existing 100 ka-Tephra record back to 133 ka BP, the end of the penultimate Glacial. The additional ca 30 m of sediments host a total number of 52 single Tephra layers forming 21 Tephra clusters that have been characterised on the basis of detailed geochemical and petrographical examinations. Tephras can be assigned to hitherto poorly known Plinian to sub-Plinian eruptive events of the nearby Campanian (Ischia Island, Phlegrean Fields), Roman (Sabatini volcanic district) and Aeolian-Sicilian volcanoes (Etna, Stromboli, Salina) and are dated according to the varve and sedimentation rate chronology of Monticchio sediments. The most prominent Tephra layers within the interval of investigation – TM-25 and TM-27 – can be firmly correlated with Ionian Sea Tephras X-5 (ca 105 ka BP) and X-6 (ca 108–110 ka BP). In addition, a further 26 Tephra layers are correlated with radiometrically and radioisotopically dated volcanic events providing the basis for a robust revised tephrochronology of the entire Monticchio sediment sequence for the last 133 ka.
