Quaternary tephra from the Valles caldera in the volcanic field of the Jemez Mountains of New Mexico identified in western Canada

John A. Westgate, Giday Woldegabriel, Henry C. Halls, Colin J. Bray, René W. Barendregt, Nick Pearce, Andrei M. Sarna-Wojcicki, Michael P. Gorton, Richard E. Kelley, Emily Schultz-Fellenz

Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

3 Dyfyniadau(SciVal)

Crynodeb

A fine-grained, up to 3-m-thick tephra bed in southwestern Saskatchewan, herein named Duncairn tephra (Dt), is derived from an early Pleistocene eruption in the Jemez Mountains volcanic field of New Mexico, requiring a trajectory of northward tephra dispersal of ~1500 km. An unusually low CaO content in its glass shards denies a source in the closer Yellowstone and Heise volcanic fields, whereas a Pleistocene tephra bed (LSMt) in the La Sal Mountains of Utah has a very similar glass chemistry to that of the Dt, supporting a more southerly source. Comprehensive characterization of these two distal tephra beds along with samples collected near the Valles caldera in New Mexico, including grain size, mineral assemblage, major- and trace-element composition of glass and minerals, paleomagnetism, and fission-track dating, justify this correlation. Two glass populations each exist in the Dt and LSMt. The proximal correlative of Dt1 is the plinian Tsankawi Pumice and co-ignimbritic ash of the first ignimbrite (Qbt1g) of the 1.24 Ma Tshirege Member of the Bandelier Tuff. The correlative of Dt2 and LSMt is the co-ignimbritic ash of Qbt2. Mixing of Dt1 and Dt2 probably occurred during northward transport in a jet stream
Iaith wreiddiolSaesneg
Tudalennau (o-i)813-828
Nifer y tudalennau16
CyfnodolynQuaternary Research
Cyfrol91
Rhif cyhoeddi2
Dyddiad ar-lein cynnar27 Rhag 2018
Dynodwyr Gwrthrych Digidol (DOIs)
StatwsCyhoeddwyd - 01 Maw 2019

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