Quaternary tephra from the Valles caldera in the volcanic field of the Jemez Mountains of New Mexico identified in western Canada. Issue 2 (27th December 2018)

• Record Type: Journal Article
• Authors: Westgate, John A.; WoldeGabriel, Giday; Halls, Henry C.; Bray, Colin J.; Barendregt, René W.; Pearce, Nicholas J.G.; Sarna-Wojcicki, Andrei M.; Gorton, Michael P.; Kelley, Richard E.; Schultz-Fellenz, Emily
• Is Part Of: Quaternary research. Volume 91:Issue 2(2019)
• Page Start: 813
• Page End: 828
• Publication Date: 2018-12-27
• Subjects: Tephra, -- Valles caldera, -- Bandelier Tuff, -- Glass, -- Trace elements, -- Fission-track dating, -- Paleomagnetism, -- Saskatchewan, -- Utah, -- New Mexico; Geology, Stratigraphic -- Quaternary -- Periodicals; Glacial epoch -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; Époque glaciaire -- Périodiques; Geology, Stratigraphic; Glacial epoch; Quaternary Geologic Period; Electronic journals; Periodicals; 551.79
• DOI: 10.1017/qua.2018.139
• Languages: English
• ISSNs: 0033-5894

Abstract

Abstract: 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.