Holocene paleomagnetic record of the North Atlantic

Author(s): Strano, S. E.; Stoner, J. S.; Ziegler, L. B.
Author Affiliation(s): Primary:
Oregon State University, College of Earth, Ocean and Atmospheric Science, Corvallis, OR, United States
Volume Title: AGU 2013 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2013; American Geophysical Union 2013 fall meeting, San Francisco, CA, Dec. 9-13, 2013. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: Terrestrial records have dominated our understanding of the Holocene paleo-geomagnetic record, while marine sediments have traditionally been used for longer-term reconstructions. Here we use seven high-resolution (∼10-65 cm/kyr) deep-sea sediment cores taken from the western (KN158-04-2GC, KN158-04-22GC and IODP Site U1305) and eastern North Atlantic (KN158-04-53GC, KN158-04-46GC, KN158-04-57GC and ODP Site 984) to constrain the full magnetic vector in the Northern North Atlantic (NNA) through the Holocene. All cores were studied by alternating field demagnetization of u-channel samples and are constrained by independent radiocarbon chronologies. Propagation of dating uncertainty between age-control points is quantified using a Monte Carlo based, random-walk model approach. In comparison to well-dated regional ultra-high resolution paleomagnetic records (MD99-2269), we see consistent bias in the radiocarbon ages of geomagnetic features in these records to nominally older ages. The bias results from delayed magnetic "lock-in" as part of the post-depositional remanent magnetization (pDRM) process. Assuming that the highest sedimentation rates provide the least biased geomagnetic age, we develop pDRM-corrected chronologies for each record by tuning paleomagnetic declination to the ultra-high resolution MD99-2269. We find that the inclination and relative paleomagnetic intensity features, which were not used in the tuning process, are more consistent between the seven records when tuned. They are most similar during the late to mid-Holocene, and show slight regional differences during the early Holocene. We create two stacks, one using the radiocarbon chronologies and the other using the pDRM-corrected chronologies and find the latter gives a clearer picture of NNA variability. We then compare with data from North America and Europe for broader regional comparisons. The well-resolved chronologies and geographical spread of the seven cores presented here will help constrain the dynamics of the high-latitude Holocene flux patches seen in geomagnetic field models.
Year of Publication: 2013
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Atlantic Ocean; Cenozoic; Expedition 303; Expeditions 303/306; Holocene; IODP Site U1305; Integrated Ocean Drilling Program; Marine sediments; North Atlantic; Northwest Atlantic; Paleomagnetism; Quaternary; Sediments
Coordinates: N572800 N572900 W0483200 W0483200
Record ID: 2015040810
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