The strategy of Expedition 391 was to core at six distributed locations on the Tristan-Gough-Walvis (TGW) hotspot track, providing new insights into the temporal, volcanologic, petrologic, geochemical and paleomagnetic evolution of the hotspot track (see Scientific objectives in the Expedition 391 summary chapter [Sager et al., 2023c]). At the youngest and westernmost of these locations, three sites were proposed as a transect across the northern Guyot Province seamounts and ridges immediately southwest of the morphologic split that occurs at about 2°E (Figure F1). Because of severe cuts to operational time on that expedition caused by COVID-19 mitigation, two proposed sites (GT-4A and TT-4A) were omitted (see Introduction in the Expedition 391 summary chapter [Sager et al., 2023c]). Only the middle site (U1578) was cored (Figures F1, F2). This omission was a major deficiency for Expedition 391, because the three holes were positioned to sample the isotopic split that first occurs farther northeast, at the location of the DSDP Leg 74 transect (Hoernle et al., 2015). By omitting the ends of the transect, only dredge samples are available to characterize the isotopic end-members, which correspond to the Tristan track (northern seamounts that connect Walvis Ridge with the Tristan Island group) and the Gough track (southern seamounts that connect Walvis Ridge to the Gough Island group).
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Expedition 391 Scientific Prospectus Addendum: Walvis Ridge Hotspot
This addendum to the International Ocean Discovery Program Expedition 391 Scientific Prospectus (Walvis Ridge Hotspot; Sager et al., 2020) incorporates minor coordinate changes to Proposed Sites CT-5A, CT-6A, TT-3A, TT-4A, TT-5A, VB-7A, VB-8A, VB-10A, VB-11A, VB-13A, and VB-14A. The revised site coordinates are documented in Proposal 890-Add2, which is available at http://iodp.tamu.edu/scienceops/expeditions/walvis_ridge_hotspot.html.
In addition, because of adjustments to the R/V JOIDES Resolution operations schedule caused by the COVID-19 pandemic, the expedition was postponed by a year. At the time of publication of this addendum, the expedition is scheduled to start in Cape Town, South Africa, on 6 December 2021 and end in Cape Town, South Africa, on 5 February 2022.
For a detailed description of the geologic background, scientific objectives, drilling and coring strategy, logging strategy, sample and data sharing strategy, and proposed sites, see Tables T1 and T2 in this report and the Expedition 391 Scientific Prospectus (Sager et al., 2020).
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- Award ID(s):
- 1326927
- NSF-PAR ID:
- 10229906
- Date Published:
- Journal Name:
- Scientific prospectus
- Volume:
- 391
- ISSN:
- 2332-1385
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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