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DOI	10.1016/j.quascirev.2018.12.026
	On the eruption age and provenance of the Old Crow tephra
	Burgess S.D.; Coble M.A.; Vazquez J.A.; Coombs M.L.; Wallace K.L.
发表日期	2019
ISSN	0277-3791
起始页码	64
结束页码	79
卷号	207
英文摘要	Tephrochronology is used to correlate and reconstruct geographically disparate sedimentary records of changing environment, climate, and landscape throughout geologic time. Single tephra layers represent isochronous markers across broad regions, thus accurate and precise radiometric constraints on the timing of eruption are critical to their utility. The Old Crow tephra is found throughout eastern Beringia and represents the largest preserved Pleistocene ashfall event in the region. Despite its volume and significance as a stratigraphic marker, the provenance of this tephra is debated, and the interpreted eruption age of marine isotope stage (MIS) 5 at ∼125 ka has vacillated. To investigate provenance and eruption age, we develop a geochemical fingerprint for the Old Crow tephra via titanomagnetite geochemistry, and zircon crystallization/cooling age via coupled U/Pb, U/Th, and (U–Th)/He zircon geochronology. Our results indicate that Old Crow oxides are geochemically distinct from the commonly assumed source-caldera system at the Emmons Lake Volcanic Center (ELVC). Zircon crystals from the Old Crow tephra range in age from Proterozoic to Pleistocene, with concordant zircon U/Pb, U/Th, and (U–Th)/He dates on the youngest population of grains suggesting crystallization in their parent magma, and in turn eruption, at 202.9 ± 9.5 ka. We discuss strengths and shortcomings of our radiogenic datasets in light of this result and review the far-reaching implications of a change in Old Crow eruption age. © 2018
英文关键词	(U–Th)/He; Beringia; Geochronlology; Marine isotope stage; Old Crow; Tephrochronology; Thermochronology; U/Pb; U/Th; Zircon
语种	英语
scopus关键词	Geochemistry; Geochronology; Isotopes; Silicate minerals; Stratigraphy; Beringia; Geochronlology; Marine isotope stages; Old Crow; Tephrochronology; Thermochronology; Zircon; Beringia; crystallization; geochronology; marine isotope stage; Pleistocene; Proterozoic; provenance; tephra; tephrochronology; titanomagnetite; zircon; Canada; Old Crow; Yukon Territory
来源期刊	Quaternary Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/152013
作者单位	U. S. Geological Survey, 345 Middlefield Road, Mail Stop 910, Menlo Park, CA 94025, United States; Stanford-USGS Ion Microprobe Laboratory, Stanford UniversityCA 94305, United States; Alaska Volcano Observatory, Volcano Science Center, U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508, United States
推荐引用方式 GB/T 7714	Burgess S.D.,Coble M.A.,Vazquez J.A.,et al. On the eruption age and provenance of the Old Crow tephra[J],2019,207.
APA	Burgess S.D.,Coble M.A.,Vazquez J.A.,Coombs M.L.,&Wallace K.L..(2019).On the eruption age and provenance of the Old Crow tephra.Quaternary Science Reviews,207.
MLA	Burgess S.D.,et al."On the eruption age and provenance of the Old Crow tephra".Quaternary Science Reviews 207(2019).