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Walvis Ridge
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2012
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Roger Revelle
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Project Title: |
Plate Tectonic and Geochemical Evolution of The Young Walvis Ridge And Implications for African Plate Motion Modeling |
Project Status: |
Submitted |
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Principal Investigator: |
Anthony A. Koppers, OSU-CEOAS |
Project Institution: |
OSU_COAS |
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Project ID: |
102135 |
Version #: |
2 |
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Date Submitted: |
8/6/2009 6:42:00 PM |
Created By: |
Anthony A. Koppers |
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Date Last Modified: |
1/19/2010 11:01:00 PM |
URI Serial #: |
None |
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Funding Agencies: |
NSF/OCE/MGG - 0961396 - Funded |
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Summary of Field Work: |
We propose that the transformation of the Walvis Ridge from an unambiguous “primary” hotspot track to diffuse volcanism is inconsistent with the classical narrow plume tail model and requires renewed scrutiny by detailed sampling and collecting a range of state-of-the-art geochronological, geochemical and geophysical data. This allows us to address the following key questions:
•What is the detailed age progression of the young end of the Walvis Ridge?
•Is diffuse volcanism in the young Walvis Ridge related to local extension, fracturing of the oceanic crust, or proximity to the Mid-Atlantic Ridge spreading center?
•Has the hotspot been geochemically zoned over all its history?
•Where is the current location of the Walvis Ridge hotspot?
•Is the Walvis Ridge hotspot failing or dying?
•What are the consequences of the answers to the above questions for hotspot fixity in the Atlantic, the Euler pole model for the African Plate, and global tectonic modeling?
To address these questions, we propose a seagoing expedition to study the young Walvis Ridge through mapping and dredging of 40 seamounts. Geochronological and geochemical data will be acquired from recovered rocks and complemented by geophysical data to resolve the local plate tectonic history and distances of the seamounts from the Mid-Atlantic Ridge (MAR) at the time of their formation. This integrated study will provide a much better understanding of time-space-chemistry relationships between the sub-tracks, their relation to structures in the underlying oceanic crust and the local plate tectonic setting, and the geochemical evolution of the overall Walvis Ridge. Combined with a German cruise (see below) to the older part of the Walvis Ridge, our new 40Ar/39Ar dates will form the basis for a revision of global plate motion models with implications for true polar wander, mantle convectional domains, and the mantle plume model, whereas the geochemistry provides unique insights into a long-lived mantle feature changing from a LIP into a robust seamount trail and ending with extremely diminished and diffuse volcanism. |
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Summary of Facility Requirements: |
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Summary of other requirements and comments: |
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Type of Request: |
Primary Ship Use |
Request Status: |
Submitted |
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Request ID: |
1003151 |
Created By: |
Anthony A. Koppers |
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Date Last Modified: |
1/19/2010 11:01:00 PM |
Date Submitted: |
8/6/2009 6:42:00 PM |
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Year: |
2012
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Ship/Facility: |
Roger Revelle
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Optimum Start Date:
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1/15/2012 |
Dates to Avoid: |
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Earliest Start Date: |
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Multi-Ship Op: |
No |
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Latest Start Date: |
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Other Ship(s): |
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Operating Days Needed: |
Science Days |
Mob Days |
De-Mob Days |
Estimated Transit Days |
Total Days |
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49 |
0 |
0 |
0 |
49 |
Repeating Cruise?
(within same year) |
No |
Interval: |
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# of Cruises: |
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Description of Repeating cruise requirements: |
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Justification/Explanation for ship choice, dates,
conflicts, number of days & multi-ship operations: |
We prefer the Melville because of its excellent multibeam performance in rough seas.
However, depending on scheduling in the South Atlantic in early 2012 we would be happy to sail on the Revelle (or Knorr) as well. |
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Short Description of Op Area
for use in schedules: |
Walvis Ridge |
| Description of Op Area: |
Our cruise focuses on the younger part (i.e. the SW section) of the Walvis Ridge in the South Atlantic, toward the E of the Mid-Atlantic Ridge and the Islands of Tristan da Cunha and Gough. The cruise will be within international waters mostly,
except for United Kingdom (Gough Island). SA3, SA4 operation areas. |
| Op Area Size/Dia.: |
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Lat/Long |
Marsden Grid |
Navy Op Area |
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Beginning
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Ending
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Show Degrees Minutes |
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Foreign Clearance Required? |
No |
Coastal States:
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 Important Info on Foreign Research Clearances
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Are you or any member in your science party bringing in any science equipment items which are regulated for export by the International Traffic in Arms Regulations (ITAR) and/or the Export Administration Regulations (EAR)?
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No |
If yes, have you applied for the necessary permits through your export control office?
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No |
| Questions about ITAR/EAR regulations?
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Comments about foreign clearance requirements or
description of any other special permitting requirements
(e.g., MMPA, ESA, IHA, Marine Sanctuaries, etc.) |
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Requested Start Port |
Intermediate Port(s) |
Requested End Port |
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Cape Town, South Africa |
None |
Cape Town, South Africa |
Explanation/justification for requested
ports and dates of intermediate stops
or to list additional port stops |
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Important Info on Working in Foreign Ports
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Chief Scientist: |
Anthony A. Koppers, OSU-CEOAS |
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# in Science Party |
18 |
# of different science teams |
1 |
# Marine Technicians to be
provided by ship operator:
(include in science party total)
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2 |
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Explanation of Science Party Requirements and Technician Requirements |
This is a dredging and multibeam mapping cruise, thus we request two good dredging technicians for around the clock dredging operations. |
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 Dynamic Positioning |  ADCP | Multibeam | Seismic |
| Dredging/Coring/Large Dia. Trawl Wire | Stern A-frame | Fiber Optic (.681) | 0.680 Coax Wire |
| SCUBA Diving | Radioisotope use - briefly describe | NO Radioisotope use/Natural level work | Other Operator Provided Inst. - Describe |
| 0 PI-Provided Vans - briefly describe | MOCNESS | | |
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Explain Instrumentation or Capability
requirements that could affect choice
of ship in scheduling. |
We need a ship that has good multibeam performance under sometimes rough sea
conditions. Dredging will also be challenging in the same weather conditions, so we
might require extra spare equipment in order to successfully finish this dredging cruise. We also will collect magnetics and gravity.
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Explain Major Ancillary Facilities
Requirements and list description
and provider for "other" systems. |
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