Age of the Mono Lake excursion and associated tephra

Authors

Larry Benson, University of Colorado at BoulderFollow
Joseph Liddicoat, Barnard College
Joseph Smoot, US Geological Survey
Andrei Sarna-Wojcicki, US Geological Survey
Robert M. Negrini, California State University - BakersfieldFollow
Steve Lund, University of Southern CaliforniaFollow

Document Type

Article

Date of this Version

2003

Citation

Quaternary Science Reviews 22 (2003) 135–140

Abstract

The Mono Lake excursion (MLE) is an important time marker that has been found in lake and marine sediments across much of the Northern Hemisphere. Dating of this event at its type locality, the Mono Basin of California, has yielded controversial results with the most recent effort concluding that the MLE may actually be the Laschamp excursion (Earth Planet. Sci. Lett. 197 (2002) 151). We show that a volcanic tephra (Ash #15) that occurs near the midpoint of the MLE has a date (not corrected for reservoir effect) of 28,620 ± 300 ¹⁴C yr BP (~32,400 GISP2 yr BP) in the Pyramid Lake Basin of Nevada. Given the location of Ash #15 and the duration of the MLE in the Mono Basin, the event occurred between 31,500 and 33,300 GISP2 yr BP, an age range consistent with the position and age of the uppermost of two paleointensity minima in the NAPIS-75 stack that has been associated with the MLE (Philos. Trans. R. Soc. London Ser. A 358 (2000) 1009). The lower paleointensity minimum in the NAPIS-75 stackis considered to be the Laschamp excursion (Philos. Trans. R. Soc. London Ser. A 358 (2000) 1009).