MagNetZ With Deepa Dwyer (2024/03/20) - Paleo-Geomagnetic Observations from Marine Sediments, Alaska
Channel: MagNetZ
Date: 2024-03-20

Paleo-Geomagnetic Field Observations from Fast Accumulating Marine Sediments obtained from a Glacial (Surveyor) Fan in the Gulf of Alaska

The video is also available for download at: https://earthref.org/ERDA/2732/
and can be referenced with the doi: 10.7288/V4/ERDA/2732

Title: Paleo-Geomagnetic Field Observations from Fast Accumulating Marine Sediments obtained from a Glacial (Surveyor) Fan in the Gulf of Alaska
Author: Deepa Dwyer from Oregon State University, USA

Due to exceptionally high sediment accumulation rates, submarine fans that are ubiquitous features of glaciated margins offer unique potential for paleo reconstructions. However, because of their highly variable accumulation rates, they are rarely exploited for high-resolution paleo studies. Here, we use an approach we call geomagnetic network analysis – (GNA), where PSV, from a small region assumed to have experienced a common geomagnetic history, is used for detailed stratigraphic alignment in depth. Here, this stratigraphic alignment is combined with a high density of radiocarbon dates from multiple records that both serve to test the synchronization and provide an age/depth transformation on single depth scale. The improved dating density facilitates a better understanding of these high and variably accumulating records. Comparison of inclination, declination, and normalized intensity from multiple holes from Sites U1417 (distal Surveyor Fan, 18 m = ~50 kyr) and U1418 (proximal Surveyor Fan, 100 m = ~50 kyr) allow both a first-order assessment of paleomagnetic patterns in these different depositional sequences and a common reconstruction of paleo-geomagnetic change. This robust, exceptionally well dated, high resolution, full vector paleo-geomagnetic reconstruction from the Gulf of Alaska for the 14-50 kyr interval, provides new insights from a region with little prior paleomagnetic data. Comparisons with available regional records and global reconstructions yield new insight into field dynamics around the Lashamp Excursion and patterns of PSV that follow.

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00:00 - Intro
00:51 - Presentation
28:48 - Questions
32:27 - Announcements