School of Geography, Earth and Atmospheric Sciences - Research Publications

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    Anchoring of atmospheric teleconnection patterns by Arctic Sea ice loss and its link to winter cold anomalies in East Asia
    Li L, M ; Luo, D ; Simmonds, I ; Dai, A ; Zhong, L ; Yao, Y (WILEY, 2021-01)
    Abstract In this paper, the physical processes underlying recent winter cold anomalies over East Asia (EA) are examined via statistical analysis. It is found that the EA cold anomaly depends on the warming in the North Atlantic, sea ice loss in the Barents–Kara Sea (BKS), and atmospheric teleconnection patterns. Specifically, the sea ice loss in the BKS can anchor teleconnection patterns originating from different North Atlantic sea surface temperature (SST) patterns. Different patterns of North Atlantic warming can affect the position of the cold anomaly region through altering the atmospheric circulations. In addition, whether the relevant teleconnection pattern leads to enhanced cold anomaly over EA crucially depends on the sea ice loss in the BKS, because it can anchor the blocking anticyclone embedded in the teleconnection pattern over the Ural region and make it more persistent and quasi‐stationary. Furthermore, it is found that the role of SST modes in the EA cold anomaly depends on their time scales. Although the strong basin‐scale warming (north–south SST tripolar mode) in the North Atlantic mid‐ to high‐latitudes plays a major role in decadal (interannual) cold anomaly over EA, it appears that the Atlantic east–west SST dipole structure dominates winter temperature variations over EA in recent decades on both the interannual and decadal time scales.
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    Spatially and Geochemically Anomalous Arc Magmatism: Insights From the Andean Arc
    Rosenbaum, G ; Caulfield, JT ; Ubide, T ; Ward, JF ; Sandiford, D ; Sandiford, M (AMER GEOPHYSICAL UNION, 2021-06)
    Abstract While most volcanic arcs show a distinctive spatial relationship to subducting plates, there are many examples where volcanoes occur in anomalous locations. These are commonly also geochemically anomalous relative to the composition of more typical subduction‐related rocks. Using Holocene volcanoes in South America as a case study, we document the spatial and geochemical patterns along the Andean volcanic belt. To determine whether spatial variations are also geochemically anomalous, we assess a series of geochemical indices that provide information on the depth and degree of melting, and the role of metasomatic subduction inputs in melt generation. We use these parameters to develop a scoring system, with the lowest and highest scores indicating “typical” and “anomalous” arc melting processes, respectively. Typical arc magmatism is defined as melts generated in the sub‐arc mantle wedge through slab‐derived fluid metasomatism, with or without contributions from subducted sediments. In contrast, we show that anomalous volcanism in South America appears to relate to geometric anomalies in the subducting Nazca plate (e.g., beneath Sumaco, Laguna Blanca and Payun Matru), or to areas affected by variations in mantle flow due to the proximity to the slab edge (Crater Basalt Volcanic Field). By establishing relationships between anomalous magmatism and slab structure, we propose that similar geochemical fingerprints could be used to explore the magmatic response to slab deformation and/or tearing in older arc systems, particularly in cases where the three‐dimensional slab structure is no longer detectable.
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    Un atto d’amore: Manifesto Open Access per la libertà, l’integrità e la creatività nelle scienze umane e nelle scienze sociali interpretative
    Pia, AE ; Batterbury, S ; Joniak-Lüthi, A ; LaFlamme, M ; Wielander, G ; Zerilli, FM ; Nolas, S-M ; Schubert, J ; Loubere, N ; Franceschini, I ; Walsh, C ; Mora, A ; Varvantakis, C (Italian Society of Cultural Anthropology (SIAC)., 2020-12-31)
    Labour of Love: An Open Access Manifesto for Freedom, Integrity, and Creativity in the Humanities and Interpretive Social Sciences, is the result of an LSE Research Infrastructure and Investment–funded workshop entitled Academic Freedom, Academic Integrity and Open Access in the Social Sciences, organised by Andrea E. Pia and held at the London School of Economics on September 9, 2019.
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    Early human occupation of southeastern Australia: New insights from 40Ar/39Ar dating of young volcanoes
    Matchan, EL ; Phillips, D ; Jourdan, F ; Oostingh, K (GEOLOGICAL SOC AMER, INC, 2020-04-01)
    Abstract In Australia, the onset of human occupation (≥65 ka?) and dispersion across the continent are the subjects of intense debate and are critical to understanding global human migration routes. New-generation multi-collector mass spectrometers capable of high-precision 40Ar/39Ar dating of young (<500 ka) samples provide unprecedented opportunities to improve temporal constraints of archaeological events. In southeastern Australia, a novel approach to improving understanding of occupation involves dating key volcanic eruptions in the region, referenced to stone artifacts and Aboriginal oral traditions. The current study focuses on two monogenetic volcanoes in the Newer Volcanic Province of southeastern Australia: Budj Bim (previously Mount Eccles) and Tower Hill. Budj Bim and its surrounding lava landforms are of great cultural significance and feature prominently in the oral traditions of the Gunditjmara people. Tower Hill is of archaeological significance due to the occurrence of a stone tool beneath tephra. 40Ar/39Ar eruption ages of 36.9 ± 3.1 ka (95% confidence interval) and 36.8 ± 3.8 ka (2σ) were determined for the Budj Bim and Tower Hill volcanic complexes, respectively. The Tower Hill eruption age is a minimum age constraint for human presence in Victoria, consistent with published optically stimulated luminescence and 14C age constraints for the earliest known occupation sites in Tasmania, New South Wales, and South Australia. If aspects of oral traditions pertaining to Budj Bim or its surrounding lava landforms reflect volcanic activity, this could be interpreted as evidence for these being some of the oldest oral traditions in existence.
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    Corrigendum to "Ultra-high precision 40Ar/39Ar ages for Fish Canyon Tuff and Alder Creek Rhyolite sanidine: New dating standards required? (vol 121, pg 229, 2013)"
    Phillips, D ; Matchan, EL (Elsevier, 2020-03-15)
    The authors regret that typographical and calculation errors occurred in Table 1, Table DR1 and Appendix A in the manuscript. Most relate to inconsistent propagation of uncertainty levels (i.e. 2σ vs 1σ uncertainties) associated with the J-values reported for FCTs and ACRs aliquots in Table DR1 and typographical errors in the J-values reported for aliquots FC3/AC3 and FC4/AC4. Corrected versions of Table 1, Figs. 3 and 4, and Appendix A are shown below. These errors do not affect the conclusions of the original paper and we summarise the resulting changes to the abstract, Sections 4.2 and 5, and Appendix A below. Correct J-values for aliquots FC3/AC3 and FC4/AC4 in Table DR1 are 0.0025205 ± 0.0000025 (0.098%; 2σ) and 0.0025295 ± 0.0000023 (0.091%; 2σ), respectively. We calculate revised eruption ages of 28.08 ± 0.04 Ma (2σ) for FCT and 1.181 ± 0.002 Ma (2σ) for ACR, relative to the astronomically calibrated age of A1 Tephra sanidine, Crete [Rivera et al. (2011) Earth Planet Sci. Lett. 311, 420–426]. R-values [Formula presented], based on mean fusion or total-gas results for the six irradiated aliquots (Table 1), range from 0.041638 ± 0.000031 (0.07%) to 0.041840 ± 0.000122 (0.29%), with a weighted mean value of 0.041680 ± 0.000050 (0.10%) (Table 1). The authors would like to apologize for any inconvenience these errors may have caused.
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    Corrigendum to "Astronomical calibration of 40Ar/39Ar reference minerals using high precision, multi-collector (ARGUSVI) mass spectrometry (vol 196, pg 351, 2017)"
    Phillips, D ; Matchan, EL ; Honda, M ; Kuiper, KF (PERGAMON-ELSEVIER SCIENCE LTD, 2020-03-15)
    The authors regret that typographical and calculation errors occurred in Table 1 and some related figures. Corrected versions of Table 1, Figs. 4–6 are reproduced below. These errors do not affect the conclusions of the original paper and we summarise the main changes to Section 4 below. We calculate revised and values of 0.041692 ± 0.000024 (0.058%) and 0.16989 ± 0.00015 (0.087%), respectively. The former value is indistinguishable from the average value of 0.041680 ± 0.000050 (0.096%) reported by Phillips and Matchan (2013) [Geochim. Cosmochim. Acta 121, 229–239]. Other corrections in Table 1 relate to typographical errors and inconsistent propagation of uncertainty levels (2σ vs 1σ uncertainties) associated with some mean and plateau ages. The authors would like to apologize for any inconvenience these errors may have caused.
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    Interpreting and reporting 40Ar/39Ar geochronologic data
    Schaen, AJ ; Jicha, BR ; Hodges, K ; Vermeesch, P ; Stelten, ME ; Mercer, CM ; Phillips, D ; Rivera, TA ; Jourdan, F ; Matchan, EL ; Hemming, SR ; Morgan, LE ; Kelley, SP ; Cassata, WS ; Heizler, MT ; Vasconcelos, PM ; Benowitz, JA ; Koppers, AAP ; Mark, DF ; Niespolo, EM ; Sprain, CJ ; Hames, WE ; Kuiper, KF ; Turrin, BD ; Renne, PR ; Ross, J ; Nomade, S ; Guillou, H ; Webb, LE ; Cohen, BA ; Calvert, AT ; Joyce, N ; Ganerod, M ; Wijbrans, J ; Ishizuka, O ; He, H ; Ramirez, A ; Pfander, JA ; Lopez-Martinez, M ; Qiu, H ; Singer, BS (GEOLOGICAL SOC AMER, INC, 2021-03-01)
    Abstract The 40Ar/39Ar dating method is among the most versatile of geochronometers, having the potential to date a broad variety of K-bearing materials spanning from the time of Earth’s formation into the historical realm. Measurements using modern noble-gas mass spectrometers are now producing 40Ar/39Ar dates with analytical uncertainties of ∼0.1%, thereby providing precise time constraints for a wide range of geologic and extraterrestrial processes. Analyses of increasingly smaller subsamples have revealed age dispersion in many materials, including some minerals used as neutron fluence monitors. Accordingly, interpretive strategies are evolving to address observed dispersion in dates from a single sample. Moreover, inferring a geologically meaningful “age” from a measured “date” or set of dates is dependent on the geological problem being addressed and the salient assumptions associated with each set of data. We highlight requirements for collateral information that will better constrain the interpretation of 40Ar/39Ar data sets, including those associated with single-crystal fusion analyses, incremental heating experiments, and in situ analyses of microsampled domains. To ensure the utility and viability of published results, we emphasize previous recommendations for reporting 40Ar/39Ar data and the related essential metadata, with the amendment that data conform to evolving standards of being findable, accessible, interoperable, and reusable (FAIR) by both humans and computers. Our examples provide guidance for the presentation and interpretation of 40Ar/39Ar dates to maximize their interdisciplinary usage, reproducibility, and longevity.
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    We studied how to reduce airborne COVID spread in hospitals. Here’s what we learnt
    Buising, K ; Marshall, C ; McGain, F ; Monty, J ; Irving, L ; Kainer, M ; Schofield, R ( 2021-08-16)
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