Ultra-high resolution late Pleistocene paleomagnetic secular variation records from the Gulf of Alaska (IODP Exp. 341 sites U1418 and U1419)

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Author(s): Velle, Julie Heggdal; St-Onge, Guillaume; Stoner, Joseph Stephen; Mix, Alan C.; Walczak, Maureen; Asahi, Hirofumi; Forwick, Matthias
Author Affiliation(s): Primary:
University of Quebec at Rimouski, Rimouski, QC, Canada
Oregon State University, United States
Korea Polar Research Institute, South Korea
Arctic University of Norway, Norway
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: IODP Expedition 341 in the Gulf of Alaska drilled the upper Surveyor Fan on the continental rise at Site U1418 (58°46.6'N 144°29.6'W; 3667 m water depth) and the continental slope at Site U1419 (59°319'N 144°8'W; 684 m water depth). U-channel paleomagnetic data has so far been collected to depths of ∼65 m (CCSF-A) at Site U1418 and ∼112 m (CCSF-A) at Site U1419. The preliminary oxygen isotope (U1418 and U1419) and radiocarbon-based age models (U1419) constrain the studied sequences to approximately 30,000 and 50,000 years, respectively. Sedimentation rates > 300 cm/kyr were resolved in some intervals, and these exceptionally expanded records allow paleomagnetic secular variation (PSV) from the northeastern Pacific to be studied in high-resolution. Alternating field (AF) demagnetization of u-channel samples and hysteresis data from Site U1418 reveal a low coercivity magnetization consistent with pseudo-single domain (PSD) magnetite with only slight down-core variations, resulting in a strong, well-defined (MAD <5°), single component magnetization being preserved. U-channel measurements of Site U1419 display a weaker, but still stable, low coercivity magnetization, also consistent with PSD magnetite as the primary remanence carrier. Inclination patterns can be correlated between Site U1418 and U1419, as well as to other regional records, suggesting that these features are geomagnetic in origin, and that the Gulf of Alaska sedimentary sequences have captured regional scale paleomagnetic secular variations. Normalization of the natural remanent magnetization (NRM) at Site U1418 with anhysteretic remanent magnetization (ARM) over 7 AF demagnetization steps are consistent with relative paleointensity, suggesting the potential for a NE Pacific regional template for stratigraphic correlation through the Late Pleistocene.
Year of Publication: 2016
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Cenozoic; Cores; East Pacific; Expedition 341; Gulf of Alaska; IODP Site U1418; IODP Site U1419; Integrated Ocean Drilling Program; Marine sediments; North Pacific; Northeast Pacific; Pacific Ocean; Paleomagnetism; Pleistocene; Quaternary; Secular variations; Sediments; Upper Pleistocene
Coordinates: N584635 N584637 W1442933 W1442936
N593155 N593156 W1440801 W1440803
Record ID: 2017062302
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