Snapshot of the Matuyama-Brunhes reversal process recorded in 40Ar/39Ar-dated lavas from Guadeloupe, West Indies

We obtain new 40Ar/39Ar ages for three lavas that record part of the Matuyama‐Brunhes geomagnetic field reversal process on Guadeloupe. These lavas record a reversed‐transitional‐reversed magnetostratigraphy and yield a weighted mean isochron age of 785.2 ± 5.2 ka (2σ analytical uncertainty) relativ...

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Bibliographic Details
Published in:Geochemistry, geophysics, geosystems : G3 geophysics, geosystems : G3, 2013-10, Vol.14 (10), p.4341-4350
Main Authors: Brown, M. C., Jicha, B. R., Singer, B. S., Shaw, J.
Format: Article
Language:English
Subjects:
Ar/Ar geochronology
Canyons
Geomagnetic field
geomagnetic reversals
Isotopes
Lava
Magma
Oxygen isotopes
paleointensity
Paleomagnetism
Potassium-argon dating
Volcanoes
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Summary:We obtain new 40Ar/39Ar ages for three lavas that record part of the Matuyama‐Brunhes geomagnetic field reversal process on Guadeloupe. These lavas record a reversed‐transitional‐reversed magnetostratigraphy and yield a weighted mean isochron age of 785.2 ± 5.2 ka (2σ analytical uncertainty) relative to an age for the Fish Canyon sanidine standard of 28.201 Ma. This age is of greater accuracy than ages obtained previously by K‐Ar dating. These lavas may record directional fluctuations occurring between the Matuyama‐Brunhes precursor and the final directional reversal. Such variations have been observed in some globally distributed coupled paleomagnetic and oxygen isotope marine sedimentary records of the Matuyama‐Brunhes reversal. Previous paleointensity estimates from these lavas indicate reduced, but fluctuating field strength during this time. Key Points New Ar/Ar dates from lavas on Guadeloupe island Lavas record part of the Matuyama‐Brunhes geomagnetic reversal process
ISSN:1525-2027
1525-2027
DOI:10.1002/ggge.20263