Developing a high-resolution paleointensity assisted chronology through the matuyama-brunhes transitional interval (0.7 to 1.25 ma) for the NE pacific from IODP Expedition 341, Sites U1417 and U1418

Author(s): Stoner, Joseph Stephen; Morey, Ann E.; Mix, Alan C.; Velle, Julie H.; St-Onge, Guillaume; Ge Shulan; Asahi, Hirofumi
Author Affiliation(s): Primary:
Oregon State University, College of Earth, Ocean, and Atmospheric Sciences, Corvallis, OR, United States
University of Quebec at Rimouski, Canada
State Oceanic Administration, China
Korea Polar Research Institute, South Korea
Volume Title: AGU 2016 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2016; American Geophysical Union 2016 fall meeting, San Francisco, CA, Dec. 12-16, 2016. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: Our understanding of the geomagnetic field and its application as a stratigraphic dating method are fundamentally limited by a lack of high quality records from many regions of the globe. The NE Pacific is one such region, not only lacking in quality paleomagnetic records, but as a region that is difficult to date using traditional Quaternary marine sediment methods, that would greatly benefit from detailed magnetic stratigraphies. We present u-channel and shipboard paleomagnetic data focusing on Matuyama-Brunhes transitional interval (∼0.7 to 1.25 Ma) from two IODP Sites (U1417 and U1418) drilled during Expedition 341 (South Alaska). Progressive AF demagnetization of u-channel samples, constrained by hysteresis data in the ∼100 to 200 m (CCSF-a) interval of Site U1417 define a well resolved, low coercivity, magnetization consistent with geocentric axial dipole expectations that improves upon reliable shipboard directions and intensities. Although ultrahigh resolution (>1 m/kyr) Site U1418 could not be u-channeled through the ∼400 to 900 m (CSF-a) rotary cored interval, correlations between u-channel data at Site U1417 and shipboard data at Site U1418 are robust enough to allow transference of its substantially more complete oxygen isotopic record to Site U1417. Passing all criteria for reliability, normalized remanence at Site U1417 using both ARM acquisition and ARM demagnetization, provides a relative paleointensity proxy that can be correlated with well-dated paleointensity stacks. This comparison allows an initial paleointensity assisted chronology to be developed; facilitating evaluation of both regional climate records through the middle Pleistocene transition, and the paleo-geomagnetic record that preserves polarity transitions, excursions, intensity variations, and secular variation during both polarities.
Year of Publication: 2016
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Brunhes Chron; Cenozoic; East Pacific; Expedition 341; Gulf of Alaska; IODP Site U1417; IODP Site U1419; Integrated Ocean Drilling Program; Marine sediments; Matuyama Chron; North Pacific; Northeast Pacific; Pacific Ocean; Paleomagnetism; Pleistocene; Quaternary; Sediments; Upper Quaternary
Coordinates: N565735 N565736 W1470635 W1473600
N593155 N593156 W1440801 W1440803
Record ID: 2017070516
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