Improved Quaternary North Atlantic stratigraphy using relative paleointensity (RPI), oxygen isotopes, and magnetic excursions

Author(s): Channell, J. E.
Author Affiliation(s): Primary:
University of Florida, Gainesville, FL, 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: Improving the resolution of Quaternary marine stratigraphy is one of the major challenges in paleoceanography. IODP Expedition 303/306, and ODP Legs 162 and 172, have yielded multiple high-resolution records (mean sedimentation rates in the 7-20 cm/kyr range) of relative paleointensity (RPI) that are accompanied by oxygen isotope data and extend through much of the Quaternary. Tandem fit of RPI and oxygen isotope data to calibrated templates (LR04 and PISO), using the Match protocol, yields largely consistent stratigraphies, implying that both RPI and oxygen isotope data are dominated by regional/global signals. Based on the recent geomagnetic field, RPI can be expected to be a global signal (i.e. dominated by the axial dipole field) when recorded at sedimentation rates less than several decimeters/kyr. Magnetic susceptibility, on the other hand, is a local/regional lithologic signal, and therefore less useful for long-distance correlation. Magnetic excursions are directional phenomena and, when adequately recorded, are manifest as paired reversals in which the virtual geomagnetic poles (VGPs) reach high latitudes in the opposite hemisphere, and they occupy minima in RPI records. Reversed VGPs imply that excursions are attributable to the main axial dipole, and therefore provide global stratigraphy. The so-called Iceland Basin excursion is recorded at many IODP/ODP sites and lies at the MIS 6/7 boundary at ≈188 ka, with a duration of 2-3 kyr. Other excursions in the Brunhes chron are less commonly recorded because their duration (perhaps <≈1 kyr) requires sedimentation rates >20 cm/kyr to be adequately recorded. On the other hand, several excursions within the Matuyama Chron are more commonly recorded in North Atlantic drift sediments due to relatively elevated durations. With some notable exceptions (e.g. Iberian Margin), high quality RPI records from North Atlantic sediments, together with magnetic excursions, can be used in tandem with oxygen isotope data to strengthen Quaternary (North Atlantic) stratigraphy.
Year of Publication: 2013
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Atlantic Ocean; Cenozoic; Expedition 303; Expeditions 303/306; Integrated Ocean Drilling Program; Isotope ratios; Isotopes; Leg 162; Leg 172; Magnetic excursions; Magnetic field; Magnetic intensity; North Atlantic; O-18/O-16; Ocean Drilling Program; Oxygen; Quaternary; Stable isotopes
Coordinates: N552838 N772026 W0062700 W0240457
N495200 N583000 W0241400 W0483200
Record ID: 2014062115
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