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Age of volcanism and its migration in the Samoa Islands

Published online by Cambridge University Press:  10 February 2010

IAN McDOUGALL
IAN McDOUGALL*
Affiliation:
Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia
*
*E-mail: [email protected]
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Abstract

Potassium–argon (K–Ar) ages on whole rock samples have been measured on lavas from the subaerial Samoa Islands, which form a broadly linear volcanic chain that extends from the ESE to the WNW for about 360 km. The Manu'a Islands near the southeast limit of the chain exhibit youthful ages, with most <0.4 Ma, in keeping with the geological observations. Tutuila consists of several volcanoes, and previous work yielded a mean K–Ar age of 1.26 ± 0.15 Ma for the shield-building volcanism. Upolu, to the WNW of Tutuila, gives a mean age of 2.15 ± 0.35 Ma for the shield-building phase, represented by the Fagaloa Volcanics, with much of the island covered by significantly younger volcanic rocks. Savai'i, further to the WNW, is dominated by youthful volcanism, extending into historic times. In a restricted area, adjacent to the NE coast of Savai'i, previously thought to have volcanic rocks correlating with the Fagaloa Volcanics of Upolu, the ages are much younger than those on Upolu, lying between 0.32 and 0.42 Ma. Considering only the subaerial volcanism from Ta'u to Upolu, but also including Vailulu'u, the volcanism has migrated in a systematic ESE direction at 130 ± 8 mm a−1 over 300 km in the last 2.2 Ma. This rate is nearly twice that obtained from GPS measurements of Pacific Plate motion of 72 mm a−1 at N64°W in this area. However, if the much older age of shield-building volcanism from the submarine foundations of Savai'i is included, the regression yields a volcanic migration rate of 72 ± 14 mm a−1, in keeping with the measured GPS rate and consistent with a hotspot origin for the island chain. This suggests that the volcanic migration rates determined from the age of subaerial volcanism can be considerably overestimated, and this is now evident in other Pacific Ocean island chains. Clearly, the ages of the main shield-building volcanism from subaerial volcanism are minima, and if the older submarine lavas can be measured, these may yield a migration rate more in keeping with current plate motions.

Keywords

K–Ar datinghotspotsSamoa Islandsvolcanism
Type
Original Article
Information
Geological Magazine , Volume 147 , Issue 5 , September 2010 , pp. 705 - 717
Copyright
Copyright © Cambridge University Press 2010

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References

Beavan, J., Tregoning, P., Bevis, M., Kato, T. & Meertens, C. 2002. Motion and rigidity of the Pacific Plate and implications for plate boundary deformation. Journal of Geophysical Research 107, doi: 10.1029/2001JB000282, 15 pp.Google Scholar
Chubb, L. J. 1957. The pattern of some Pacific island chains. Geological Magazine 94, 221–8.Google Scholar
Dana, J. D. 1849. Geology. United States Exploring Expedition during the years 1838–1842 under the command of Charles Wilkes, U. S. N., 10, 307–36. Philadelphia: C. Sherman.Google Scholar
Daly, R. A. 1924. The geology of American Samoa. Carnegie Institution of Washington Publication 340, 95–143.Google Scholar
DeMets, C. & Dixon, T. H. 1999. New kinematic models for Pacific-North America motion from 3 Ma to present; I: Evidence for steady motion and biases in the NUVEL-1A model. Geophysical Research Letters 26, 1921–4.CrossRefGoogle Scholar
Duncan, R. A. 1985. Radiometric ages from volcanic rocks along the New Hebrides–Samoa lineament. In Geological Investigations of the Northern Melanesian Borderland (ed. Brocher, T. M.), pp. 67–76. Circum-Pacific Council for Energy and Mineral Resources Earth Science Series 3. Houston, Texas: Circum-Pacific Council for Energy and Mineral Resources.Google Scholar
Duncan, R. A. & McDougall, I. 1976. Linear volcanism in French Polynesia. Journal of Volcanology and Geothermal Research 1, 197–227.CrossRefGoogle Scholar
Friedländer, I. 1910. Beiträge zur Geologie der Samoainseln. Abhandlungen der bayerischen Academie der Wissenschaften, Mathematisch–physikalische Klasse 24, 507–41.Google Scholar
Gaina, C., Müller, R. D. & Cande, S. C. 2000. Absolute plate motion, mantle flow, and volcanism at the boundary between the Pacific and Indian Ocean mantle domains since 90 Ma. In The History and Dynamics of Global Plate Motions (eds Richards, M. A., Gordon, R. G. & van der Hilst, R. D.), pp. 189–210. American Geophysical Union Geophysical Monograph no. 121.Google Scholar
Gradstein, F., Ogg, J. & Smith, A. 2004. A Geologic Time Scale 2004. Cambridge: Cambridge University Press.Google Scholar
Hart, S. R., Staudigel, H., Koppers, A. A. P., Blusztajn, J., Baker, E. T., Workman, R., Jackson, M., Hauri, E., Kurz, M., Sims, K., Fornari, D., Saal, A. & Lyons, S. 2000. Vailulu'u undersea volcano: The new Samoa. Geochemistry Geophysics Geosystems 1, doi:2000GC000108, 13 pp.CrossRefGoogle Scholar
Hart, S. R., Coetzee, M., Workman, R. K., Blusztajn, J., Johnson, K. T. M., Sinton, J. M., Steinberger, B. & Hawkins, J. W. 2004. Genesis of the Western Samoa seamount province: age, geochemical fingerprint and tectonics. Earth and Planetary Science Letters 227, 37–56.CrossRefGoogle Scholar
Hawkins, J. W. & Natland, J. H. 1975. Nephelinites and basanites of the Samoan linear volcanic chain: Their possible tectonic significance. Earth and Planetary Science Letters 24, 427–39.CrossRefGoogle Scholar
Jackson, M. G., Hart, S. R., Koppers, A. A. P., Staudigel, H., Konter, J., Blusztajn, J., Kurz, M. & Russell, J. A. 2007. The return of subducted continental crust in Samoan lavas. Nature 448, 684–7.Google Scholar
Jensen, H. I. 1907. The geology of Samoa, and the eruptions in Savai'i. Proceedings of the Linnean Society of New South Wales 31, 641–72.Google Scholar
Kear, D. & Wood, B. L. 1959. The Geology and Hydrology of Western Samoa. New Zealand Geological Survey Bulletin n.s. 63, 92 pp.Google Scholar
Keating, B. 1985. Paleomagnetic studies of the Samoan Islands: Results from the islands of Tutuila and Savaii. In Geological Investigations of the Northern Melanesian Borderland (ed. Brocher, T. M.), pp. 187–99. Circum-Pacific Council for Energy and Mineral Resources Earth Science Series 3. Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources.Google Scholar
Keating, B. H. 1992. The geology of the Samoan Islands. In Geology and Offshore Mineral Resources of the Central Pacific Basin (eds Keating, B. H. & Bolton, B. R.), pp. 127–78. Circum-Pacific Council for Energy and Mineral Resources Earth Science Series 14. New York: Springer-Verlag.Google Scholar
Kidane, T., Otofuji, Y.-I., Brown, F. H., Takemoto, K. & Eshete, G. 2007. Two normal paleomagnetic polarity intervals in the lower Matuyama Chron recorded in the Shungura Formation (Omo Valley, Southwest Ethiopia). Earth and Planetary Science Letters 262, 240–56.CrossRefGoogle Scholar
Koppers, A. A. P., Russell, J. A., Jackson, M. G., Konter, J., Staudigel, H. & Hart, S. R. 2008. Samoa reinstated as a primary hotspot trail. Geology 36, 435–8.Google Scholar
Matsuda, J.-I., Notsu, K., Okano, J., Yaskawa, K. & Chungue, L. 1984. Geochemical implications from Sr isotopes and K–Ar age determinations for the Cook-Austral islands chain. Tectonophysics 104, 145–54.CrossRefGoogle Scholar
McDougall, I. 1985. Age and evolution of the volcanoes of Tutuila, American Samoa. Pacific Science 39, 311–20.Google Scholar
McDougall, I. & Duncan, R. A. 1980. Linear volcanic chains – Recording plate motions? Tectonophysics 63, 275–95.Google Scholar
McDougall, I. & Duncan, R. A. 1988. Age progressive volcanism in the Tasmantid Seamounts. Earth and Planetary Science Letters 89, 207–220.Google Scholar
McDougall, I. & Feibel, C. S. 1999. Numerical age control for the Miocene–Pliocene succession at Lothagam, a hominoid-bearing sequence in the northern Kenya Rift. Journal of the Geological Society, London 156, 731–45.CrossRefGoogle Scholar
Montelli, R., Nolet, G., Dahlen, F. A., Masters, G., Engdahl, E. R. & Hung, S.-H. 2004. Finite-frequency tomography reveals a variety of plumes in the mantle. Science 303, 338–43.Google Scholar
Morgan, W. J. 1971. Convection plumes in the lower mantle. Nature 230, 42–3.CrossRefGoogle Scholar
Morgan, W. J. & Phipps Morgan, J. 2007. Plate velocities in the hotspot reference frame. In Plates, Plumes, and Planetary Processes (eds Foulger, G. R. & Jurdy, D. M.), pp. 65–78. Geological Society of America, Special Paper no. 430.Google Scholar
Natland, J. H. 1980. The progression of volcanism in the Samoan linear volcanic chain. American Journal of Science 280A, 709–35.Google Scholar
Natland, J. H. & Turner, D. L. 1985. Age progression and petrological development of Samoan shield volcanoes: Evidence from K–Ar ages, lava compositions, and mineral studies. In Geological Investigations of the Northern Melanesian Borderland (ed. Brocher, T. M.), pp. 139–71. Circum-Pacific Council for Energy and Mineral Resources Earth Science Series 3. Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources.Google Scholar
Price, R. C., Maillet, P., McDougall, I. & Dupont, J. 1991. The geochemistry of basalts from the Wallis Islands, Northern Melanesian Borderland: Evidence for a lithospheric origin for Samoan-type basaltic magmas? Journal of Volcanology and Geothermal Research 45, 267–88.CrossRefGoogle Scholar
Sella, G. F., Dixon, T. H. & Mao, A. 2002. REVEL: A model for Recent plate velocities from space geodesy. Journal of Geophysical Research 107, doi: 10.1029/2000JB000033, 30 pp.Google Scholar
Stearns, H. T. 1944. Geology of the Samoan Islands. Bulletin of the Geological Society of America 55, 1279–1331.Google Scholar
Steiger, R. H. & Jäger, E. 1977. Subcommission on geochronology: Convention on the use of decay constsnts in geo- and cosmochronology. Earth and Planetary Science Letters 36, 359–62.Google Scholar
Stice, G. D. & McCoy, F. W. Jr. 1968. The geology of the Manu'a Islands, Samoa. Pacific Science 22, 427–57.Google Scholar
Tarling, D. H. 1965. The palaeomagnetism of the Samoan and Tongan Islands. Geophysical Journal of the Royal Astronomical Society 10, 497–513.Google Scholar
Thomson, J. A. 1921. The geology of Western Samoa. New Zealand Journal of Science and Technology 4, 49–66.Google Scholar
Wilson, J. T. 1963. A possible origin of the Hawaiian Islands. Canadian Journal of Physics 41, 863–70.CrossRefGoogle Scholar
Workman, R. K., Hart, S. R., Jackson, M., Regelous, M., Farley, K. A., Blusztajn, J., Kurz, M. & Staudigel, H. 2004. Recycled metasomatized lithosphere as the origin of the Enriched Mantle II (EM2) end-member: Evidence from the Samoan volcanic chain. Geochemistry Geophysics Geosystems 5, doi: 10.1029/2003GC000623, 44 pp.CrossRefGoogle Scholar
Wright, E. & White, W. M. 1986/87. The origin of Samoa: new evidence from Sr, Nd and Pb isotopes. Earth and Planetary Science Letters 81, 151–62.CrossRefGoogle Scholar