Refining the Late Quaternary tephrochronology for southern South America using the Laguna Potrok Aike sedimentray record
Dr Victoria C. Smith
Associate Professor, Head of Tephrochronology Group
+44 (0)1865 285202
Research Interests
Tephrochronology, geochronology, volcanology and igneous petrology
Primary Geographic Area
Japan, Italy (Campi Flegrei volcano), Mexico City, Patagonia (Chile).
Research Profile
Research Activities
I am an Associate Professor, Senior Research Fellow in tephrochronology in the Research Laboratory for Archaeology and the History of Art in the School for Archaeology. I obtained my PhD in Geology from the University of Auckland, New Zealand and I was a postdoctoral fellow in the Department of Earth Sciences, University of Bristol from 2006 until 2009.
My research focuses on large explosive eruptions and in particular their age, composition, and magnitude. I use this information to gain understanding on the tempo of explosive eruptions and establish their impact. The glass and mineral compositions of the volcanic deposits (tephra) serve as chemical fingerprints of specific eruptions that allow us to correlate and synchronise records that contain the volcanic ash even if it can only be identified with a microscope. These correlations allow us to map the full extent of the tephra dispersal, refine age models and constrain the eruption ages, and precisely link palaeoclimate and/or archaeological records. This allows us to identify temporal and spatial variations in eruptions, climate and/or culture.
Links
Publications
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Evidence for a large-magnitude eruption from Campi Flegrei caldera (Italy) at 29 ka
Albert, PG, Giaccio, B, Isaia, R, Costa, A, Niespolo, EM, Nomade, S, Pereira, A, Renne, PR, Hinchliffe, A, Mark, DF, Brown, RJ, Smith, VC2019|Journal article|Geology -
Geochemical characterisation of the Late Quaternary widespread Japanese tephrostratigraphic markers and correlations to the Lake Suigetsu sedimentary archive (SG06 core)
Albert, PG, Smith, VC, Suzuki, T, McLean, D, Tomlinson, EL, Miyabuchi, Y, Kitaba, I, Mark, DF, Moriwaki, H, Nakagawa, T2019|Journal article|Quaternary Geochronology© 2019 Large Magnitude (6–8) Late Quaternary Japanese volcanic eruptions are responsible for widespread ash (tephra) dispersals providing key isochrons suitable for the synchronisation and dating of palaeoclimate archives across East Asia, the NW Pacific and beyond. The transfer of geochronological information using these eruption deposits demands robust tephra correlations underpinned by detailed and precise volcanic glass geochemical data. Presented here is a major (electron microprobe; EMP) and trace element (Laser ablation inductively coupled plasma mass spectrometry; LA-ICP-MS) characterisation of near-source deposits from a series of large magnitude Japanese eruptions spanning approximately the last 150 ka. These data offer new insights into diagnostic compositional variations of the investigated volcanic sources spanning the Japanese islands. Whilst in the case of the highly productive Aso caldera (Kyushu), we are able to explore compositional variations through successive large magnitude eruptions (50–135 ka). These near-source volcanic glass data are used to validate and refine the visible tephrostratigraphy of the intensely dated Lake Suigetsu sedimentary record (SG06 core), Honshu Island, whilst also illustrating key tephrostratigraphic tie points to other East Asian palaeoclimate records (e.g. Lake Biwa). The identification of widespread Japanese tephrostratigraphic markers in the SG06 sediment record enables us to place chronological constraints on these ash dispersals, and consequently explosive volcanism at source volcanoes situated along the Kyushu Arc, including Kikai, Ata and Aso calderas. The proximal Aso-4 Ignimbrite (Magnitude 7.7) deposit is dated here by 40Ar/39Ar at 86.4 ± 1.1 ka (2σ), and provides a chronological anchor (SG06-4963) for the older sediments of the Lake Suigetsu record. Finally, trace element glass data verify visible ash fall layers derived from other compositionally distinct source regions of Japanese volcanism, including activity along the northern Izu-Bonin arc and North East Japan Arcs. These findings underline the Lake Suigetsu record as central node in the Japanese tephrostratigraphic framework. -
The Ilopango Tierra Blanca Joven (TBJ) eruption, El Salvador: Volcano-stratigraphy and physical characterization of the major Holocene event of Central America
Pedrazzi, D, Sunye-Puchol, I, Aguirre-Díaz, G, Costa, A, Smith, VC, Poret, M, Dávila-Harris, P, Miggins, DP, Hernández, W, Gutiérrez, E2019|Journal article|Journal of Volcanology and Geothermal Research© 2019 Elsevier B.V. The Ilopango caldera is the source of the large Tierra Blanca Joven (TBJ) eruption that occurred about 1.5 ka years ago, between ca. AD270 and AD535. The eruption dispersed volcanic ash over much of the present territory of El Salvador, and pyroclastic density currents (PDCs) extended 40 km from the volcano. In this study, we document the physical characteristics of the deposits from all over El Salvador to further constrain the eruption processes and the intensity and magnitude of the different phases of the eruption. The succession of deposits generated by the TBJ eruption is made of 8 units. The eruption started with PDCs of hydromagmatic origin (Unit A0), followed by fallout deposits (Units A and B) that are <15 cm thick and exposed in sections close to the Ilopango caldera (within 10–15 km). The eruption, then, transitioned into a regime that generated further PDCs (Units C–F), these range from dilute to dense and they filled the depressions near the Ilopango caldera with thicknesses up to 70 m. Deposits from the co-ignimbrite plume (Unit G) are the most widespread, the deposits are found in Guatemala, Honduras, Nicaragua, Costa Rica and the Pacific Ocean and cm-thick across El Salvador. Modelling of the deposits suggests that column heights were 29 km and 7 km for the first two fallout phases, and that the co-ignimbrite phoenix plume rose up to 49 km. Volumes estimated for the fallout units are 0.15, 0.8 and 16 km3 dense rock equivalent (DRE) for Unit A, B and G respectively. The PDCs deposits volumes were estimated to be ~0.5, ~3.3, ~0.3 and ~9.1 km3 DRE for Units C, D, E and F, respectively. The combined volume of TBJ deposits is ~30 km3 DRE (~58 km3 bulk rock), indicating that it was one of largest Holocene eruptions from Central America. This eruption occurred while Mayan populations were living in the region and it would have had a significant impact on the areas within tens of kilometres of the vent for many years to decades after the eruption. -
Constraints on the frequency and dispersal of explosive eruptions at Sambe and Daisen volcanoes (South-West Japan Arc) from the distal Lake Suigetsu record (SG06 core)
Albert, PG, Smith, VC2018|Journal article|Earth-Science Reviews© 2018 Elsevier B.V. Accurately evaluating the tempo and magnitude of pre-historic eruptions is essential for hazard assessments. Here we demonstrate the importance of integrating records from locations close to the volcano with those in distal regions to generate more comprehensive event stratigraphies. The annually laminated (varved) and intensely radiocarbon dated lacustrine sediments of Lake Suigetsu (SG06 core), Japan are used to place chronological constraints on the tempo of volcanism at two stratovolcanoes located favourably upwind of the lake along the South-West Japan Arc, Sambe and Daisen. Major and trace element glass compositions are used to assign visible ash (tephra) layers preserved in the SG06 sediment core to past explosive eruptions from these volcanoes. Integrating these stratigraphies confirm that the ~150 ka long lake sequence records nine visible ash layers from Daisen and five from Sambe. The SG06 record captures two periods of closely spaced eruptions at Daisen volcano. The first period begins at ~61.1 ka with three explosive eruptions over ~10 ka, with two events separated by as little as 1.5 ka. One layer (SG06–4281), dated at 59.6 ± 5.5 ka (95.4% probability), relates to the large magnitude, and widely dispersed Daisen Kurayoshi Pumice (DKP) eruption. The other period of frequent activity began at 29,837 ± 96 IntCal13 yrs. BP (95.4% probability) with five widely dispersed ash fall events associated with explosive eruptions separated by approximately 6, 936, 5 and 438 years. The integrated proximal-distal event stratigraphy and the high-precision SG06 chronology provide unique insights into the timing and frequency of past explosive volcanism from Daisen and Sambe, which has implications for the prediction of future eruption scenarios.
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Teaching
Postgraduate teaching
Course convenor and lecturer for the MSc/MSt in Archaeological Science.
