28 research outputs found
Tephrostratigraphy of the late glacial and Holocene sediments of Puyehue Lake (Southern Volcanic Zone, Chile, 40°S)
Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Quaternary Research 70 (2008): 343-357, doi:10.1016/j.yqres.2008.06.001.We document the mineralogical and geochemical composition of tephra layers identified in
the late Quaternary sediments of Puyehue Lake (Southern Volcanic Zone of the Andes, Chile,
40°S) to identify the source volcanoes and to present the first tephrostratigraphic model for the
region. For the last millennium, we propose a multi-criteria correlation model based on five
tephra layers identified at seven coring sites. The two upper tephras are thin fine-grained green
layers composed of more than 80% rhyodacitic glass shards, and associated to the AD 1960 and
AD 1921-22 eruptions of the Puyehue-Cordon de Caulle volcanic complex. The third tephra is a
sandy layer dominated by orthopyroxene, and related to the AD 1907 eruption of Rininahue
maar. An olivine-rich tephra was deposited at the end of the 16th century, and a tephra
characterized by a two pyroxene association marks the second half of the first millennium AD. In
addition, we detail the tephra succession of an 11.22 m long sediment core covering the last
18,000 years. The results demonstrate that the central province of the Southern Volcanic Zone
has been active throughout the last deglaciation and the Holocene, with no increase in volcanic
activity during glacial unloading.The ENSO-Chile project is supported by the Belgian Federal Office for Scientific, Technical
and Cultural Affairs (OSTC)
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