Open AccessSnapshot of the Matuyama‐Brunhes reversal process recorded in 40 Ar/ 39 Ar‐dated lavas from Guadeloupe, West Indies
Author(s) -
Brown M. C.,
Jicha B. R.,
Singer B. S.,
Shaw J.
Publication year - 2013
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/ggge.20263
Subject(s) - geology , isochron , paleomagnetism , geomagnetic reversal , sanidine , geochronology , paleontology , magnetostratigraphy , lava , isotopes of oxygen , k–ar dating , seismology , volcano , geochemistry , biotite , magnetic field , physics , quartz , quantum mechanics
We obtain new 40 Ar/ 39 Ar 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 (2 σ 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.