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Hardman-Mountford, N.
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- PublicationRestrictedGeochemistry of the Phlegraean Fields (Italy) proximal sources for major Mediterranean tephras: Implications for the dispersal of Plinian and co-ignimbritic components of explosive eruptions(2012-05)
; ; ; ; ; ; ; ; ; ; ; ; ;Tomlinson, E. L.; Department of Earth Sciences, Royal Holloway University of London, ;Arienzo, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Civetta, L.; Dipartimento di Scienze Fisiche, Universita` di Napoli Federico II, Napoli, Italy ;Wulf, S.; GFZ German Research Centre for Geosciences ;Smith, V. C.; Research Laboratory for Archaeology and the History of Art, University of Oxford ;Hardiman, M.; Centre of Quaternary Research, Department of Geography, Royal Holloway University of London ;Lane, C. S.; Centre of Quaternary Research, Department of Geography, Royal Holloway University of London ;Carandente, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Orsi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Rosi, M.; Dipartimento di Scienze della Terra, Universita` di Pisa, ;Muller, W.; Department of Earth Sciences, Royal Holloway University of London ;Menzies, M. A.; Department of Earth Sciences, Royal Holloway University of London; ; ; ; ;; ; ; ; ; ; Volcanic activity at Phlegraean Fields, Italy, produced several major marker tephras over a 50 ka period. The caldera forming eruptions of the Campanian Ignimbrite (CI) and Neapolitan Yellow Tuff (NYT) are of particular importance for tephrostratigraphy in Europe. Other key eruptions from this source include the Pomici Principali (PP) and the Tufi Biancastri eruptions. We combine analyses of fresh glasses from proximal locations (i.e., juvenile clasts in proximal flow and fall deposits) with data for key tephra layers from Lago Grande di Monticchio, 120 km to the east. The micron-beam major (EMPA) and trace (LA-ICP-MS) element glass dataset allows us to: (a) distinguish between tephra units produced from the Phlegraean Fields before and during the CI eruption (CI-series), and before and during the NYT and PP eruptions (NYT-series/PP); (b) discriminate between the CI and the geochemically similar Pre-CI pyroclastic deposits; (c) separate the NYT from Pre-NYT tephra units, although both major and trace elements do show significant overlap. The complex compositional overlap between Pre-NYT tephras may present a problem for tephra correlations in the 14–39 ka time window and may have resulted in incorrect proximal–distal and distal–distal correlations. The diagnostic chemical criteria detailed herein permits more accurate matching of distal tephras with their proximal equivalents and hence will improve chronostratigraphy of distal settings and give insight into tephra dispersal. We show that the dispersal of PP tephra was more limited than previously thought. The surge/fall (Lower Member) and subsequent pyroclastic density current (Upper Member) phases of the NYT eruption can be recognised in distal settings. Both the NYT Lower and Upper Members are found in distal localities to the east of the Phlegraean Fields, however the Lower Member is found in the absence of the Upper Member in locations to the far north of Phlegraean Fields. Chemical compositions of the Plinian and ignimbrite phases of the CI eruption overlap extensively, but can be distinguished on a plot of Zr–Th.383 29 - PublicationOpen AccessBiogeographic validation of a global ocean biogeochemical model(2008)
; ; ; ;Vichi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Allen, J. I.; PML, UK ;Hardman-Mountford, N.; PML, UK; ; Currently biogeochemical models of the global ocean focus on simulating the coupling between prevalent physical conditions and the biogeochemical processes with the underlying assumption that coherent biological properties are a direct (or modulated) response to physics. This is one possible biogeographic characterisation of the pelagic environment, since biogeochemistry represents only one aspect of marine ecosystems. Several models are currently capable of simulating the chlorophyll distribution observed from space, though an objective validation with respect to relevant ecosystem properties is still lacking. In this paper we analyse the results of one of the most comprehensive models of ocean biogeochemistry with an emphasis on biogeographic validation sensu Longhurst (Ecological Geography of the Sea, 2007, 2nd edition, Academic Press). A set of multivariate statistical tools, Multi Dimensional Scaling (MDS) and Principal Components Analysis (PCA), are used to verify the existence of pre-defined biogeographic provinces and their statistical significance. The MDS ordination indicates that the given provinces are recognizable in the model on the basis of the selected variables. Analysis of Similarity (ANOSIM) shows that the provinces are statistically separable and they can be more easily distinguished in terms of their environmental features rather than their biology. The underlying relationships between the physical and biological properties are investigated through correlation analyses, thus providing some insights on how the model reproduces features characteristic of the various regions. Satellite chlorophyll data have been used to demonstrate external validation at the biogeographic level. The a priori provinces as characterised by chlorophyll values cannot be statistically separated in either the data or the model. It is likely this is related to the arbitrary choice of province boundaries, which are not necessarily the same as those derivable from non-interpolated SeaWiFS data. The PCA comparison of modelled and observed chlorophyll demonstrated some objective skill in the model as it generally captures the dominant mode of the data, although severe mismatch was identified in certain regions by visual comparison (Indian and Southern Oceans). The model also overestimated seasonal variability compared to the data. The method shows promise for helping overcome problems with model verification due to undersampling of most ocean biogeochemical variables.172 420 - PublicationRestrictedThe emergence of ocean biogeochemical provinces: a quantitative assessment and a diagnostic for model evaluation.(2011)
; ; ; ; ;Vichi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Allen, J. I.; PML ;Masina, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Hardman-Mountford, N.; PML; ; ; The concept of ocean biogeochemical provinces is based on the observation that large ocean regions are characterized by coherent physical forcing and environmental conditions, which are eventually representative of macroscale ocean ecosystems. Biogeochemical models of the global ocean focus on simulating the coupling between prevalent physical conditions and the biogeochemical processes with the assumption that biological properties respond coherently to physics and therefore should produce such provinces as an emergent property. In this paper, we quantitatively assess the emergence of a reference set of predefined biogeochemical provinces in the available global data sets and propose a province‐based approach to the evaluation of one of the most comprehensive models of ocean biogeochemistry. Multivariate statistical tools were applied to model and observation data, verifying the existence, distinctiveness and reliability of the predefined provinces and quantifying the correlation of model results with observations at the global scale. The analysis of similarity between provinces shows that they are statistically separable in data and model output and therefore can be used as reliable metrics. The analyses indicate that provinces can be more easily distinguished in terms of their environmental features rather than using chlorophyll concentration. The characterization of provinces by means of chlorophyll values shows a significant overlap in both the Sea‐viewing Wide Field‐of‐view Sensor (SeaWiFS) data and the model. It is likely this is related to the choice of province boundaries based on coarse‐resolution mapped data, which are not necessarily the same as those derivable from high‐resolution satellite data. We also demonstrated through cluster analysis that the long‐term time series data collected at Joint Global Ocean Flux Study (JGOFS) stations are representative of environmental conditions of the respective province and can thus be used to evaluate model results extracted from that province. The method shows promise for helping to overcome problems with model verification due to under sampling of most ocean biogeochemical variables but also gives indications that unsupervised clustering may be required when more spatially resolved data and models are available.391 83 - PublicationRestrictedVolcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards(2012-08)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Lowe, J.; Department of Geography, Royal Holloway University of London ;Barton, N.; Institute of Archaeology, Oxford University, ;Blockley, S.; Department of Geography, Royal Holloway University of London ;Ramsey, C. B.; Research Laboratory for Archaeology and the History of Art, Oxford University, ;Cullen, V. L.; Research Laboratory for Archaeology and the History of Art, Oxford University, ;Davies, W.; Archaeology Department, University of Southampton, National Oceanography Centre ;Gamble, C.; Archaeology Department, University of Southampton, National Oceanography Centre ;Grant, K.; School of Ocean and Earth Science, University of Southampton, ;Hardiman, M.; Department of Geography, Royal Holloway University of London, ;Housley, R.; Department of Geography, Royal Holloway University of London, ;Lane, C. S.; Research Laboratory for Archaeology and the History of Art, Oxford University, ;Lee, S.; Research Laboratory for Archaeology and the History of Art, Oxford University, ;Lewis, M.; Palaeontology Department, Natural History Museum, London ;MacLeod, A.; Department of Geography, Royal Holloway University of London, ;Menzies, M. A.; gDepartment of Earth Sciences, Royal Holloway University of London ;Muller, W.; gDepartment of Earth Sciences, Royal Holloway University of London ;Pollard, M.; Research Laboratory for Archaeology and the History of Art, Oxford University, ;Price, C.; Institute of Archaeology, Oxford University, ;Roberts, A. P.; Research School of Earth Sciences, Australian National University, ;Rohling, E. J.; School of Ocean and Earth Science, University of Southampton ;Satow, C.; Department of Geography, Royal Holloway University of London, ;Smith, V. C.; Research Laboratory for Archaeology and the History of Art, Oxford University, ;Stringer, C. B.; Palaeontology Department, Natural History Museum, London ;Tomlinson, E. L.; Department of Earth Sciences, Royal Holloway University of London ;White, D.; Institute of Archaeology, Oxford University, ;Albert, P.; Department of Earth Sciences, Royal Holloway University of London, ;Arienzo, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Barker, G.; McDonald Institute for Archaeological Research, University of Cambridge ;Boric, D.; Cardiff School of History, Ancient History, Archaeology and Religion, Cardiff University, ;Carandente, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Civetta, L.; Dipartimento di Scienze Fisiche, Università Federico II, 80126 Naples, ;Ferrier, C.; De la Préhistoire à l’Actuel: Culture, Environnement et Anthropologie, Préhistoire, Palèoenvironnement, Patrimonie, Unité Mixte de Recherche 5199 Centre National de la Recherche Scienti!que, Université Bordeaux ;Guadelli, J. L.; De la Préhistoire à l’Actuel: Culture, Environnement et Anthropologie, Préhistoire, Palèoenvironnement, Patrimonie, Unité Mixte de Recherche 5199 Centre National de la Recherche Scienti!que, Université Bordeaux ;Karkanas, P.; Ephoreia of Palaeoanthropology–Speleology of Southern Greece, 116 36 Athens, Greece; ;Koumouzelis, M.; Ephoreia of Palaeoanthropology–Speleology of Southern Greece, 116 36 Athens, Greece ;Muller, U.; Institute of Geosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany; ;Orsi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Pross, J.; Institute of Geosciences, Goethe University Frankfurt, ;Rosi, M.; Dipartimento di Scienze della Terra, Università di Pisa ;Shalamanov-KorobarKorobas, L.; National Institution Museum of Macedonia, ;Sirakov, N.; National Institute of Archaeology and Museum of Bulgarian Academy of Sciences ;Tzedakis, P. C.; Department of Geography, University College London; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results con!rm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters.310 27