Identification of a Kulshan caldera correlative tephra in the Palouse loess of Washington State, northwest USA

Details

Serval ID
serval:BIB_23C6F02E1AB0
Type
Article: article from journal or magazin.
Collection
Publications
Title
Identification of a Kulshan caldera correlative tephra in the Palouse loess of Washington State, northwest USA
Journal
Quaternary Research
Author(s)
King Georgina E., Pearce Nicholas J.G., Roberts Helen M., Smith Victoria C., Westgate John A., Gaylord David R., Sweeney Mark R.
ISSN
0033-5894
1096-0287
Publication state
Published
Issued date
09/2016
Peer-reviewed
Oui
Volume
86
Number
02
Pages
232-241
Language
english
Abstract
The Kulshan caldera formed at ∼1.15 Ma on the present-day site of Mt. Baker, Washington State, northwest USA and erupted a compositionally zoned (dacite-rhyolite) magma and a correlative eruptive, the Lake Tapps tephra. This tephra has previously been described, but only from the Puget Lowland of NW Washington. Here an occurrence of a Kulshan caldera correlative tephra is described from the Quaternary Palouse loess at the Washtucna site (WA-3). Site WA-3 is located in east-central Washington, ∼340 km southeast of the Kulshan caldera and ∼300 km east-southeast of the Lake Tapps occurrence in the Puget Lowland. Major- and trace element chemistry and location of the deposit at Washtucna within reversed polarity sediments indicates that it is not correlative with the Mesa Falls, Rockland, Bishop Ash, Lava Creek B or Huckleberry Ridge tephras. Instead the Washtucna deposit is related to the Lake Tapps tephra by fractional crystallisation, but is chemically distinct, a consequence of its eruption from a compositionally zoned magma chamber. The correlation of the Washtucna occurrence to the Kulshan caldera-forming eruption indicates that it had an eruptive volume exceeding 100 km3, and that its tephra could provide a valuable early-Pleistocene chronostratigraphic marker in the Pacific Northwest.
Keywords
Kulshan caldera, Lake Tapps tephra, Palouse loess, Trace element geochemistry
Web of science
Create date
14/08/2018 6:47
Last modification date
23/12/2022 16:14
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