Bridging the gap: 40Ar/39Ar dating of volcanic eruptions from the ‘Age of Discovery’
Mark, Darren F.
Cohen, Benjamin E.
Chamberlain, Katy J.
Brown, Richard J.
AffiliationIsotope Geoscience Unit, Scottish Universities Environmental Research Centre, East Kilbride
Department of Earth & Environmental Science, University of St Andrews, St Andrews
School of Environmental Sciences, University of East Anglia, Norwich
Department of Natural Sciences, University of Derby, Derby
School of History, University of East Anglia, Norwich
British Geological Survey, The Lyell Centre, Edinburgh
Department of Earth Sciences, Durham University, Durham
TIA Systems Ltd., Cheadle
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AbstractMany volcanoes worldwide still have poorly resolved eruption histories, with the date of the last eruption often undetermined. One such example is Ascension Island, where the timing of the last eruption, and consequently, the activity status of the volcano, is unclear. Here, we use the 40Ar/39Ar dating technique to resolve ages of the three youngest lava flows on the island, which are hawaiites and mugearite with 1.5 – 1.9 wt% K2O. In dating these lavas, we provide the first evidence of Holocene volcanic activity on Ascension (0.51 ± 0.18 ka; 0.55 ± 0.12 ka; 1.64 ± 0.37 ka), determining that it should be classed as an active volcanic system. In addition, we demonstrate that the 40Ar/39Ar method can reproducibly date mafic lava flows younger than 1 ka, decreasing the gap between recorded history and geological dating. These results offer new prospects for determining patterns of late-Holocene volcanic activity; critical for accurate volcanic hazard assessment.
CitationPreece, K., Mark, D.F., Barclay, J., Cohen, B.E., Chamberlain, K.J., Jowitt, C., Vye-Brown, C., Brown, R.J. and Hamilton, S., (2018). 'Bridging the gap: 40Ar/39Ar dating of volcanic eruptions from the ‘Age of Discovery’'. Geology, 46(12), pp, 1-12. DOI: 10.1130/g45415.1.
PublisherGeological Society of America