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Description
The hydrothermal system of the Vailulu'u volcano that is located to the East of Ta'u island in the Samoan Islands has been investigated by measuring standard CTD, nephelometry and fluorometry onboard the US Coast Guard Polar Sea. Vailulu'u marks the current location of the Samoan hotspot. This Microsoft Excel file contains the CTDNF data in three Excel spreadsheets with useful plotting utilities to display the CTDN data at any scale. SAM18 is an extensive Tow-Yo transect from the out- to inside on the E-side of the crater. Compare with SAM19. In total 36 up and down legs were carried out reaching ~960 m water depth. Power mode. |
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Geological Age Range and Timescale
1 - 0 Ma, Holocene |
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Location
14º 12.73' S 169º 03.44' W, Pacific Ocean, American Samoa, Vailulu'u Volcano, Rockne Seamount, Samoan Islands, Samoan Hotspot Trail |
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Instructions
The data are presented as Excel spreadsheets with useful plotting utilities to display the CTDNF data at any scale. This display can be adjusted by checking the checkboxes in the legend, by choosing different parameters for plotting and by choosing the appropriate ranges on the axes. Click on the ¿redraw¿ button to refresh the chart. Each spreadsheet contains an ¿info¿ sheet with the basic parameters describing the CTDNF casts and a table defining all the down, up and horizontal legs in the hydrocast. This sheet also contains a table defining all parameters (including there column number and label) that can be found in the ¿header¿ and ¿data¿ sheets. When opening the Microsoft Excel file be sure to ¿enable macros¿ in order to activate the Visual Basic plotting software. |
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Keywords
Underwater Volcano, Volcanic Crater, Hydrothermal System, Seamount, Hotspot, CTD, Nephelometry, SeaBIRD, Fluorometry |
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Project -- Other Projects -- Vailulu'u: the Active Samoan Hotspot Volcano
Vailulu'u Seamount is identified as an active volcano marking the current location of the Samoan hotspot. This seamount is located 45 km east of Ta¿u Island, Samoa, at 169¿03.5¿W, 14¿12.9¿S. Vailulu'u defines the easternmost edge of the Samoan Swell, rising from 5000m ocean floor to a summit depth of 590m, and marked by a 400m deep and 2 km wide summit crater. Its broad western rift and stellate morphology brand it as a juvenile progeny of Ta¿u. Seven dredges, ranging from the summit to the SE Rift zone at 4200m, recovered only alkali basalts and picrites. Isotopically, the volcano is strongly EM2 in character and clearly of Samoan pedigree (87Sr/86Sr: 0.7052-0.7067; 143Nd/144Nd: 0.51267-0.51277; 206Pb/204Pb: 19.19-19.40). 210Po-210Pb data on two summit basalts indicate ages younger than 50 years; all of the recovered rocks are extremely fresh, and veneered with glass. An earthquake swarm in early 1995 may attest to a recent eruption cycle. |
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