Quaternary tephra from the Valles caldera in the volcanic field of the Jemez Mountains of New Mexico identified in western Canada
- Univ. of Toronto, ON (Canada). Dept. of Earth Sciences
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Univ. of Lethbridge, Lethbridge, Alberta (Canada). Dept. of Geography
- Aberystwyth Univ., Wales (United Kingdom). Dept. of Geography and Earth Sciences
- U.S. Geological Survey, Menlo Park, CA (United States)
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. Finally, 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.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- Natural Sciences and Engineering Research Council of Canada (NSERC); USDOE
- Grant/Contract Number:
- 89233218CNA000001
- OSTI ID:
- 1495150
- Report Number(s):
- LA-UR-18-21041
- Journal Information:
- Quaternary Research, Vol. 91, Issue 2; ISSN 0033-5894
- Publisher:
- University of Washington - Cambridge University PressCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Tephra glass chemistry provides storage and discharge details of five magma reservoirs which fed the 75 ka Youngest Toba Tuff eruption, northern Sumatra
|
journal | October 2019 |
Similar Records
Is the Valles caldera entering a new cycle of activity?
Isotopic and trace element characteristics of rhyolites from the Valles Caldera, New Mexico. Final technical report