000 03468nam a2200433Ia 4500
001 96267
041 _aInglés
084 _a15272-a
100 _aFontijn, Karen
245 0 _aTephra glass geochemistry to synchronise sedimentary records and understand regional eruptive histories: a postglacial tephrochronological model for the Chilean Lake District
260 _c2016
300 _adigital (S2.9)
500 _aVolcanic Hazard and Risk Assessment S2.9
520 _aWell-characterised tephra horizons deposited in various sedimentary environments provide a means of synchronising sedimentary archives and obtaining accurate chronological controls of past explosive eruptions. The use of tephra as a chronological tool is however still widely underutilised in southern Chile and Argentina. In this study we develop a postglacial tephrochronological model for the Chilean Lake District (ca. 38 to 42 °S) by integrating terrestrial and lacustrine records. Tephra deposits preserved in lake sediments record discrete events even if they do not correspond to primary fallout, and provide the most complete temporal records of recurrent ash fall impact in a given region. By combining terrestrial with lacustrine records we obtain the most complete tephrostratigraphic record for the area to date. Our open access glass geochemical and chronological dataset provides insights into the frequency and magnitude of large explosive eruptions impacting the Chilean Lake District throughout the postglacial. Most volcanoes in the studied segment of the Southern Volcanic Zone, between Llaima and Calbuco, have produced at least one regional marker deposit resulting from a large explosive eruption (magnitude ? 4), some of which now have a significantly improved age estimate. Others, including several units from Puyehue-Cordón Caulle, are newly described. We also find tephra related to the Cha1 eruption from Chaitén volcano in lake sediments up to 400 km north from source. Several clear marker horizons are now identified that will help refine age model reconstructions for various sedimentary archives. Our chronological model suggests three distinct phases of eruptive activity impacting the area, with an early-to-mid-Holocene period of relative quiescence. Extending our tephrochronogical framework further south into Patagonia will allow a more detailed evaluation of the controls on the occurrence and magnitude of explosive eruptions throughout the postglacial.
650 _a REGION 09
650 _a REGION 10
650 _a CHILE
650 _a LAGOS
700 _aRawson, Harriet
700 _a Van Daele, Maarten
700 _a Moernaut, Jasper
700 _a Abarzúa, Ana M.
700 _a Heirman, Katrien
700 _a Bertrand, Sébastien
700 _a Pyle, D.M.
700 _a Mather, Tamsin A.
700 _a De Batist, Marc
700 _a Naranjo S., José Antonio
700 _a Moreno R., Hugo
773 _tConference Cities on Volcanoes 9o., Puerto Varas, Chile, November 20-25, 2016
942 _cARTC
991 _aAnalíticas
008 220218s9999 xx 000 0 und d
999 _c257546