The South Pacific Superswell
2011; American Geophysical Union; Linguagem: Inglês
10.1029/gm043p0025
ISSN2328-8779
Autores Tópico(s)High-pressure geophysics and materials
ResumoThe South Pacific Superswell Marcia K. Mcnutt, Marcia K. Mcnutt Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, cambridgeSearch for more papers by this authorKaren M. Fischer, Karen M. Fischer Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, cambridgeSearch for more papers by this author Marcia K. Mcnutt, Marcia K. Mcnutt Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, cambridgeSearch for more papers by this authorKaren M. Fischer, Karen M. Fischer Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, cambridgeSearch for more papers by this author Book Editor(s):Barbara H. Keating, Barbara H. KeatingSearch for more papers by this authorPatricia Fryer, Patricia FryerSearch for more papers by this authorRodey Batiza, Rodey BatizaSearch for more papers by this authorGeorge W. Boehlert, George W. BoehlertSearch for more papers by this author First published: 01 January 1987 https://doi.org/10.1029/GM043p0025Citations: 104Book Series:Geophysical Monograph Series AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onEmailFacebookTwitterLinkedInRedditWechat Summary Seafloor depths in a broad area of French Polynesia are 250 to 750 m shallower than lithosphere of the same age in the North Pacific and the North Atlantic. The area of shallow seafloor also correlates with a region of high density of volcanoes, low seismic velocity in the upper mantle, and a reduction in the thickness of the elastic plate supporting the volcanoes. The Marquesas fracture zone marks an abrupt transition between normal lithosphere to the north which follows the thermal subsidence curve for a 125-km-thick plate and shallow lithosphere to the south which behaves as though it is only 75-km thick. This age dependence in the French Polynesian depth anomalies, the low elastic plate thickness, and the change in depth at the Marquesas fracture zone, a lithospheric discontinuity, require elevated temperatures in the lithosphere. The pattern and amplitude of the depth anomaly is not consistent with the notion that it results from lithospheric thinning beneath a number of overlapping hot spot swells. Rather, we propose that hot spot traces cluster in this region because the lithosphere is already thinner and more vulnerable to magma penetration. The reduction in the thickness of the thermal plate is presumably due to enhanced small-scale convection resulting from the thermal and/or chemical effect of a broad mantle up welling beneath the South Pacific as imaged by seismic tomography. The morphologic and petrologic characteristics of this superswell resemble those that existed in the mid-Cretaceous over H. W. Menard's Darwin Rise, a region of the Pacific which includes the Mid-Pacific Mountains, the Marshall Islands, Magellan Seamounts, and Wake Guyots. We propose that the South Pacific superswell is the modern-day equivalent of the Darwin Rise, and that it may be merely an extreme example of global variability in lithospheric thermal structure as a function of temperature, chemistry, and/or state-of-stress in the upper mantle. References E. Bonatti, C. G. A. Harrison, Hot lines in the Earth's mantle, Nature, 263, 402– 404, 1976. 10.1038/263402a0 Web of Science®Google Scholar S. Calmant, A. Cazenave, Worldwide estimates of the oceanic lithosphere elastic thickness under volcanoes, Nature, 1987. Google Scholar S. Cande, Nazca-South America plate interactions since 50 m.y.b.p. in Peru-Chile Trench offshore Peru, Ocean Margin Drilling Program Regional Atlas Series, Atlas, 9, Sheet 14, Marine Science International, Woods Hole, Massachusetts, 1986. Google Scholar J. R. Cochran, Variations in subsidence rates along intermediate and fast spreading mid-ocean ridges, Geophys. J. Roy. Astr. Soc., 87, 421– 454, 1986. 10.1111/j.1365-246X.1986.tb06631.x Web of Science®Google Scholar J. R. Cochran, M. Talwani, Gravity anomalies, regional elevation, and the deep structure of the North Atlantic, J. Geophys. Res., 83, 4907– 4924, 1978. 10.1029/JB083iB10p04907 Web of Science®Google Scholar K. C. Creager, T. H. Jordan, Slab penetration into the lower mantle beneath the Mariana and other island arcs in the Northwest Pacific, J. Geophys. Res., 91, 3573– 3589, 1986. 10.1029/JB091iB03p03573 Web of Science®Google Scholar S. T. Crough, Thermal origin for mid-plate hot-spot swells, Geophys. J. Roy. Astron. Soc., 55, 451– 459, 1978. 10.1111/j.1365-246X.1978.tb04282.x PubMedWeb of Science®Google Scholar S. T. Crough, R. D. Jarrard, The Marquesas-Line swell, J. Geophys. Res., 86, 11,763– 11,771, 1981. 10.1029/JB086iB12p11763 Web of Science®Google Scholar R. S. Detrick, S. T. Crough, Island subsidence, hot spots, and lithospheric thinning, J. Geophys. Res., 83, 1236– 1244, 1978. 10.1029/JB083iB03p01236 Web of Science®Google Scholar R. S. Dietz, H. W. Menard, Hawaiian swell, deep, and arch, and subsidence of the Hawaiian Islands, J. Geol., 61, 99– 113, 1953. 10.1086/626059 Web of Science®Google Scholar R. A. Duncan, I. McDougall, Linear volcanism in French Polynesia, J. Volcan. Geotherm. Res., 1, 197– 227, 1976. 10.1016/0377-0273(76)90008-1 Web of Science®Google Scholar A. M. Dziewonski, J. H. Woodhouse, Global images of the Earth's interior, Science, 236, 37– 48, 1987. 10.1126/science.236.4797.37 CASPubMedWeb of Science®Google Scholar L. Fleitout, C. Froidevaux, D. Yuen, Active lithospheric thinning, Tectonophysics, 132, 271– 278, 1986. 10.1016/0040-1951(86)90037-5 Web of Science®Google Scholar L. Fleitout, D. Yuen, Steady-state, secondary convection beneath lithospheric plates with temperature and pressure-dependent viscosity, J. Geophys. Res., 89, 9227– 9244, 1984. 10.1029/JB089iB11p09227 Web of Science®Google Scholar P. L. Firstbrook, B. M. Funnell, A. M. Hurley, A. G. Smith, Paleoceanic Reconstructions 0-160 Ma, Deep Sea Drilling ProjectLa Jolla, 1979. Google Scholar K. M. Fischer, M. K. McNutt, L. Shure, Thermal and mechanical constraints on the lithosphere beneath the Marquesas swell, Nature, 332, 733– 736, 1986. 10.1038/322733a0 Web of Science®Google Scholar GEBCO General Bathymetric Chart of the Ocean, 5, Canadian Hydrographic office, 1978. Google Scholar R. G. Gordon, and L. J. Henderson, Pacific plate hot spot tracks, unpublished preprint, 1985. Google Scholar B. H. Hager, and R. W. Clayton, Constraints on the structure of mantle convection using seismic observations, flow models, and the geoid, in Mantle Convection, W. R. Peltier, ed., in press, 1987. Google Scholar D. W. Handschumacher, Post-Eocene plate tectonics of the Eastern Pacific, The Geophysics of the Pacific Ocean Basin and Its Margins, Geophysical Monograph, 19, G. H. Sutton, M. H. Manghnani, R. Moberly, American Geophysical Union, Washington, D. C., 1976. 10.1029/GM019p0177 Google Scholar S. R. Hart, A large-scale isotope anomaly in the Southern Hemisphere mantle, Nature, 309, 753– 757, 1984. 10.1038/309753a0 CASWeb of Science®Google Scholar W. F. Haxby, J. K. Weissel, Evidence for small-scale mantle convection from Seasat altimeter data, J. Geophys. Res., 91, 3507– 3520, 1986. 10.1029/JB091iB03p03507 Web of Science®Google Scholar T. H. Jordan, Mineralogies, densities, and seismic velocities of garnet lherzolites and their geophysical implications, The Mantle Sample: Inclusions in Kimberlites and Other Volcanics, F. R. Boyd, H. O. A. Meyer, 1– 14, American Geophysical Union, Washington, D.C., 1979. 10.1029/SP016p0001 Web of Science®Google Scholar S. Le Douran, B. Parsons, A note on the correction of ocean floor depths for sediment loading, J. Geophys. Res., 87, 4715– 4722, 1982. 10.1029/JB087iB06p04715 Web of Science®Google Scholar W. J. Ludwig, and R. E. Houtz, Isopach map of sediments in the Pacific Ocean Basin and marginal sea basins, Amer. Assoc. Petrol. Geol. Map Series, 1979. Google Scholar J. Mammerickx, R. N. Anderson, H. W. Menard, S. M. Smith, Morphology and tectonic evolution of the East-Central Pacific, Geol. Soc. Amer. Bull., 86, 111– 118, 1975. 10.1130/0016-7606(1975)86 2.0.CO;2 Web of Science®Google Scholar D. J. Matthews, Tables of the Velocity of Sound in Pure Water and Sea Water, Hydrographic Department, Admiralty, London, 1939. Google Scholar M. K. McNutt, Lithospheric flexure and thermal anomalies, J. Geophys. Res., 89, 11180– 11194, 1984. 10.1029/JB089iB13p11180 Web of Science®Google Scholar M. K. McNutt, Temperature beneath midplate swells: the inverse problem, in Seamounts, Islands, and Atolls, B. Keating, and R. Batiza, Eds., American Geophysical Union, Geophys. Monogr. Ser., 43, 1987. 10.1029/GM043p0123 Google Scholar M. K. McNutt, H. W. Menard, Lithospheric flexure and uplifted atolls, J. Geophys. Res., 83, 1206– 1212, 1978. 10.1029/JB083iB03p01206 Web of Science®Google Scholar H. W. Menard, Archipelagic aprons, Amer. Assoc. Petrol. Geol. Bull., 40, 2195– 2210, 1956. Google Scholar H. W. Menard, Marine Geology of the Pacific, 271, McGraw-Hill, New York, 1964. Google Scholar H. W. Menard, Depth anomalies and the bobbing motion of drifting islands, J. Geophys. Res., 78, 5128– 5137, 1973. 10.1029/JB078i023p05128 Web of Science®Google Scholar H. W. Menard, Darwin Reprise, J. Geophys. Res., 89, 9960– 9968, 1984. 10.1029/JB089iB12p09960 Web of Science®Google Scholar H. W. Menard, M. K. McNutt, Evidence for and consequences of thermal rejuvenation, J. Geophys. Res., 87, 8570– 8580, 1982. 10.1029/JB087iB10p08570 Web of Science®Google Scholar J. Morgan, Plate motions and deep mantle convection, Mem. Geol. Soc. Amer., 132, 7– 22, 1972. 10.1130/MEM132-p7 Google Scholar J. H. Natland, E. Wright, Magmatic lineages and mantle sources of Cretaceous seamounts in the Central Pacific, EOS, Trans. Amer.Geophys.Union, 65, 1075– 1076, 1984. Google Scholar C. E. Nishimura, D. W. Forsyth, Anomalous Love-wave phase velocities in the Pacific: sequential pure-path and spherical harmonic inversion, Geophys. J. R. Astr. Soc., 81, 389– 407, 1985. 10.1111/j.1365-246X.1985.tb06409.x Web of Science®Google Scholar B. Parsons, D. McKenzie, Mantle convection and the thermal structure of the plates, J. Geophys. Res., 83, 4485– 4496, 1978. 10.1029/JB083iB09p04485 Web of Science®Google Scholar B. Parsons, J. G. Sclater, An analysis of the variation of ocean floor bathymetry and heat flow with age, J. Geophys. Res, 82, 803– 827, 1977. 10.1029/JB082i005p00803 Web of Science®Google Scholar M. Renkin, J. G. Sclater, Age, depth, and residual depth anomalies in the North Pacific: implications for thermal models of the lithosphere and upper mantle, J. Geophys. Res., 1987. Google Scholar M. A. Richards, B. H. Hager, The earth's geoid and the large-scale structure of mantle convection, Proceedings of the NATO Advanced Study Institute: "The Physics of Planets", University of Newcastle-Upon-TyneApril, 1985. Google Scholar E. M. Robinson, B. Parsons, S. F. Daly, The effect of a shallow low-viscosity zone on the apparent compensation of midplate swells, Earth Planet. Sci. Letts., 82, 335– 348, 1987. 10.1016/0012-821X(87)90207-X Web of Science®Google Scholar J. G. Sclater, J. Francheteau, The implications of terrestrial heat-flow observations on current tectonic and geochemical models of the crust and upper mantle of the earth, Geophys. J. R. Astr. Soc., 20, 509– 542, 1970. 10.1111/j.1365-246X.1970.tb06089.x Web of Science®Google Scholar J. G. Sclater, B. Parsons, C. Jaupart, Oceans and continents: similarities and differences in mechanisms of heat loss, J. Geophys. Res., 86, 11,535– 11,552, 1981. 10.1029/JB086iB12p11535 Web of Science®Google Scholar J. Talandier, E. A. Okal, Crustal structure in the Society and Tuamotu Islands, French Polynesia, Geophys. J. R. Astr. Soc., 88, 499– 528, 1987. 10.1111/j.1365-246X.1987.tb01644.x Web of Science®Google Scholar R. Van Wykhouse, SYNBAPS, Tech. Rept. TR-233, National Oceanographic officeWashington, D. C., 1973. Google Scholar Citing Literature Seamounts, Islands, and Atolls, Volume 43 ReferencesRelatedInformation
Referência(s)