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Eruption Age of a Pleistocene Basalt From ^(40)Ar-^(39)Ar Analysis of Partially Degassed Xenoliths

Gillespie, A. R. and Huneke, J. C. and Wasserburg, G. J. (1983) Eruption Age of a Pleistocene Basalt From ^(40)Ar-^(39)Ar Analysis of Partially Degassed Xenoliths. Journal of Geophysical Research B, 88 (B6). pp. 4997-5008. ISSN 0148-0227. https://resolver.caltech.edu/CaltechAUTHORS:20140115-132130945

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Abstract

We have applied ^(40)Ar−^(39)Ar dating to potassium-rich granitic xenoliths and host basalt from the Pleistocene Big Pine volcanic field, California. These xenoliths had been partially degassed upon their inclusion in the basaltic lava. Argon released from the xenoliths at extraction temperatures below ∼900°C yielded plateau ages indistinguishable from the total K-Ar age of the basalt. The best estimate of the age of eruption was 1.18±0.05 (2σ) m.y. ^(40)Ar extracted at higher temperatures included radiogenic argon not degassed from the late Cretaceous xenoliths 1.18 m.y. ago, causing an increase in the apparent age for the high-temperature fractions. The agreement of the low-temperature xenolith plateau ages and the basalt K-Ar ages demonstrates that ^(40)Ar−^(39)Ar analysis of xenoliths may be used to measure the age of eruption of very young lavas. This is significant because in many instances ages cannot be reliably determined by analysis of the lavas themselves.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/JB088iB06p04997DOIArticle
http://onlinelibrary.wiley.com/doi/10.1029/JB088iB06p04997/abstractPublisherArticle
ORCID:
AuthorORCID
Wasserburg, G. J.0000-0002-7957-8029
Additional Information:© 1983 American Geophysical Union. Received August 13, 1982; revised March 1, 1983; accepted March 1, 1983. Filippo Radicati di Brozolo assisted during early ^(40)Ar-^(39)Ar analyses and gave unstintingly of his time and advice. Theodore Wen measured K concentrations for several preliminary samples. We thank G. Brent Dalrymple and Derek York for their thoughtful criticisms of the article. This research was supported by NSF grants EAR 78-01787 and EAR 79-19997. Contribution 3506 (364) of the Division of Geological and Planetary Sciences, California Institute of Technology.
Funders:
Funding AgencyGrant Number
NSFEAR 78-01787
NSFEAR 79-19997
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences3506
Lunatic Asylum Lab364
Issue or Number:B6
Record Number:CaltechAUTHORS:20140115-132130945
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140115-132130945
Official Citation:Glllespie, A. R., J. C. Huneke, and G. J. Wasserburg (1983), Eruption age of a Pleistocene basalt from 40Ar−39Ar analysis of partially degassed xenoliths, J. Geophys. Res., 88(B6), 4997–5008, doi:10.1029/JB088iB06p04997.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43388
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:15 Jan 2014 22:40
Last Modified:09 Mar 2020 13:19

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