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The five primary sites proposed for International Ocean Discovery Program (IODP) Expedition 395, which was postponed because of the COVID-19 pandemic, were cored during IODP Expedition 395C. The Expedition 395C operations, shipboard measurements, and sampling were adjusted to account for the absence of a sailing science party. The Expedition 395/395C objectives are (1) to investigate temporal variations in ocean crust generation at the Reykjanes Ridge and test hypotheses for the influence of Iceland mantle plume fluctuations on these processes, (2) to analyze sedimentation rates at the Björn and Gardar contourite drifts, as proxies for Cenozoic variations of North Atlantic deepwater circulation, and for uplift and subsidence of the Greenland-Scotland Ridge gateway related to plume activity, and (3) to analyze the alteration of oceanic crust and its interaction with seawater and sediments. During Expedition 395C, basalt cores were collected at four sites: U1554, U1555, U1562, and U1563. Sediment cores were also collected from these sites as well as from Site U1564, and casing was installed to 602 m at Site U1554. The amount of recovered cores, their preliminary descriptions, and the analyses of shipboard samples show that the results of Expedition 395C will fulfill a significant part of the Expedition 395 objectives. Basalts were collected from two V-shaped ridge and trough pairs, which will allow the investigation of the variability in mantle source and temperature causing this ridge/trough pattern. Basalt cores span an expected age range of 2.8–13.9 Ma, which will allow us to investigate the hydrothermal weathering processes. Sediments from the Björn drift were cored to basement, along with the uppermost 600 m of sediments from the Gardar drift. The data provided by Expedition 395C are a major advancement in achieving the work of Expedition 395.
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This content will become publicly available on June 1, 2026
Geomagnetic Excursions Recorded in North Atlantic IODP Expedition 395C Sites U1555 and U1563
Abstract By studying deep‐sea drilled records from the North Atlantic Ocean, several magnetic instabilities of short duration, such as the Iceland Basin (188 ka), the Björn (1,255 ka) and the Gardar (1,460 ka) excursions, were discovered. These records have contributed to our understanding of Earth's magnetic field and are the foundation of the Geomagnetic Instability Time Scale (GITS) in the Quaternary. Here, we present the magnetostratigraphy from Sites U1555 (0 to ∼2.7 Ma) and U1563 (0 to ∼5.2 Ma) drilled during the International Ocean Discovery Program Expedition 395C on the eastern side of the modern Mid‐Atlantic Ridge (∼60°N, 20–30°W). Shipboard paleomagnetic and microfossil data provided a preliminary age model, extending the regional record to 3.4 Ma. The Virtual Geomagnetic Pole latitudes from archive halves, corroborated with data from discrete samples, were used to build a high‐resolution magnetostratigraphy, which contained the expected Brunhes and Matuyama Chrons and their respective Subchrons. We also identified most of the magnetic events reported in the GITS, including the less well‐documented ones, such as Osaka, Kamitzukara, Huckleberry Ridge, Reunion, Gardar, Halawa and L4 events. The high‐resolution magnetostratigraphy from Sites U1555 and U1563 is compared with two previous legacy sites and contributes toward an increasingly robust GITS, expanding its use as a correlation and dating tool.
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- Award ID(s):
- 2238290
- PAR ID:
- 10647202
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Wiley on behalf of the American Geophysical Union
- Date Published:
- Journal Name:
- Geochemistry, Geophysics, Geosystems
- Volume:
- 26
- Issue:
- 6
- ISSN:
- 1525-2027
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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