Stratigraphy, age and correlation of Lepue Tephra: a widespread c. 11 000 cal a BP marker horizon sourced from the Chaiten Sector of southern Chile
Outes, Valeria
- 1University of Auckland
- 2Universidad de Chile
- 3Aberystwyth University
- 4
- 5Victoria University Wellington
- 6Pontificia Universidad Catolica de Chile
- 7Universidad Nacional del Comahue
Journal
Journal of Quaternary Science
ISSN
0267-8179
1099-1417
Open Access
green
Volume
32
Start page
795
End page
829
We describe the stratigraphy, age and correlation of a prominent tephra marker, named Lepue Tephra, extensively distributed in north-western Patagonia. Lepue Tephra is well dated at c. 11 000 cal a BP from numerous lake and soil cover-bed sequences and its recognition is useful for assessing the rate and timing of deglaciation as well as associated environmental changes in this region during the last glacial termination and early Holocene. Lepue Tephra has attributes typical of a complex and compositionally zoned phreatomagmatic eruptive. While the initial rhyolitic phase can be readily distinguished from multiple eruptive products sourced from the adjacent Volcan Chaiten, the main erupted end member is of basaltic-andesitic bulk composition-similar to younger tephras sourced from Holocene monogenetic cones adjacent to the Volcan Michimahuida massif (tMim). Lepue Tephra can be correlated to an equivalent-aged pyroclastic flow deposit (Amarillo Ignimbrite) prominently distributed in the south-eastern sector of tMim. The source vent for these co-eruptive events is obscured by an extensive ice field and is currently unknown. The widespread radially symmetrical distribution of Lepue Tephra centred on tMim cannot be attributed solely to volcanological considerations. Reduced Southern Hemisphere westerly wind influence interpreted from climate proxies at the time of eruption are also implicated. Copyright (C) 2017 John Wiley & Sons, Ltd.
Name
Allowayetal.2017c-JQS-Lepue.pdf
Size
5.66 MB
Format
Adobe PDF
Checksum
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