title: A pulse of mid-Pleistocene rift volcanism in Ethiopia at the dawn of modern humans.
abstract: The Ethiopian Rift Valley hosts the longest record of human co-existence with volcanoes on Earth, however, current understanding of the magnitude and timing of large explosive eruptions in this region is poor. Detailed records of volcanism are essential for interpreting the palaeoenvironments occupied by our hominin ancestors; and also for evaluating the volcanic hazards posed to the 10 million people currently living within this active rift zone. Here we use new geochronological evidence to suggest that a 200 km-long segment of rift experienced a major pulse of explosive volcanic activity between 320 and 170 ka. During this period, at least four distinct volcanic centres underwent large-volume (>10 km3) caldera-forming eruptions, and eruptive fluxes were elevated five times above the average eruption rate for the past 700 ka. We propose that such pulses of episodic silicic volcanism would have drastically remodelled landscapes and ecosystems occupied by early hominin populations.
authors.affiliation: Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK.
authors.forename: William
authors.initials: W
authors.lastname: Hutchison
authors.affiliation: School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Fusillo
authors.affiliation: Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK.
authors.forename: David M
authors.identifier: 0000-0002-2663-9940
authors.initials: DM
authors.lastname: Pyle
authors.affiliation: Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK.
authors.forename: Tamsin A
authors.identifier: 0000-0003-4259-7303
authors.initials: TA
authors.lastname: Mather
authors.affiliation: School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK.
authors.forename: Jon D
authors.initials: JD
authors.lastname: Blundy
authors.affiliation: School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK.
authors.forename: Juliet
authors.initials: J
authors.lastname: Biggs
authors.affiliation: School of Earth Sciences, University of Addis Ababa, PO Box 1176, Addis Ababa, Ethiopia.
authors.forename: Gezahegn
authors.initials: G
authors.lastname: Yirgu
authors.affiliation: NERC Argon Isotope Facility, Scottish Universities Environmental Research Centre, Rankine Avenue, East Kilbride G75 0QF, UK.
authors.forename: Benjamin E
authors.initials: BE
authors.lastname: Cohen
authors.affiliation: School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Brooker
authors.affiliation: NERC Argon Isotope Facility, Scottish Universities Environmental Research Centre, Rankine Avenue, East Kilbride G75 0QF, UK.
authors.forename: Dan N
authors.initials: DN
authors.lastname: Barfod
authors.affiliation: U.S. Geological Survey, 345 Middlefield Road, MS-937, Menlo Park, California 94025, USA.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Calvert