A Reassessment of the Matuyama–Brunhes Boundary Age Based on the Post-depositional Remanent Magnetization (PDRM) Lock-In Effect for Marine Sediments
The age of the Matuyama–Brunhes (M–B) boundary has been estimated from the astronomical ages of marine sediments and the 40Ar/39Ar ages of volcanic rocks. Although the accepted age for the M–B boundary is 780 ka, recent studies have questioned conventional estimates of the boundary age. In this paper, I present clear evidence for the existence of errors in palaeomagnetic dating due to the effect of the post-depositional remanent magnetization (PDRM) lock-in depth, based on a comparison between previously published marine isotope ages for the M–B boundary and sedimentation rates. These findings indicate that the age of the M–B boundary should be revised to ca. 770–773 ka and that the boundary most likely lies in the late Marine Isotope Stage (MIS) 19 rather than in the middle of MIS 19. This new age for the M–B boundary is consistent with that obtained from the EPICA Dome C ice core using an EDC3 age model. In contrast, an age offset for the M–B boundary is recognized between marine sediments and 40Ar/39Ar ages. To resolve this discrepancy, additional data are required from marine sediments, volcanic rocks, and ice cores.
KeywordsMatuyama–Brunhes boundary Marine sediments 40Ar/39Ar age Post-depositional remanent magnetization (PDRM) Lock-in depth
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