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    GEOPHYSICALRESEARCH LETTERS, VOL. 24, NO. 15,PAGES 1955-1958, AUGUST 1, 1997 Seamountabundances and abyssalhill morphology on the eastern flank of the East Pacific Rise at 14øS IngoGrevemeyer, 12Vincent Renard, 3Claudia Jennrich, • and Wilfried Weigel I Abstract. Bathymetricdata from a Hydrosweepmultibeam hills. Abyssalhills in the PacificOcean form. primarily sonarsurvey of a 720 km longtectonic corridor on theeast througha complexcombination of volcanicconstructional flank of the southernEPR at 14ø14'S coveredabout 25,000 processesand faulting that occur at or nearthe ridgeaxis km2 of zero-ageto 8.5 m.y. old crust(magnetic anomaly [e.g., Golf, 1991; MacdonaMet al., 1996]. Stochastic 4A). In this corridorwe documenta strongcorrelation of analysisof abyssalhills have shownthat ridge flank robustalong flowline changes in abyssalhill morphologyroughness increases with decreasing spreading rate [Menard, and seamountsize distributionwith spreadingrate changes 1967;Malinverno, 199l; Goff, 199l]. Nevertheless,seafloor deducedfrom our magneticdata. Indeed, we find thatboth roughnessvalues show a largevariation along a single rmsheight of abyssalhills andabundance and height of spreadingsegment [Golf, 1991; Goffet al., 1993],suggesting seamountsincrease significantly as spreadingrate changes that spreadingrate cannotbe the solefactor governing from ~ 75 mm/yrto over 85 mm/yr(half rate). Moreover, variationsin abyssalhill morphology. we identified 46 seamountstaller than !.00 m. Previous From November 8 to December 30, 1995 the R/V Sonne studieson the southernEPR reporteda larger densityof carriedout the EXCO-cruise,a geophysicalsurvey on zero- seamounts,organized primarily in chains.Our investigation, age to about8.5 m.y. old seafloor created at the"superfast" however, revealed seamountsnot associatedwith major spreading(full rate >140 mm/yr) East Pacific Rise south of chains,leading us to theconclusion that different forms of the Garrettfracture zone [Weigelet al., 1996].
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  • The Propagation of Seafloor Spreading in the Southwestern Subbasin, South China Sea
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  • Seafloor Spreading
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  • Plate Tectonics, Seafloor Spreading, and Continental Drift: an Lntroduction1 Rhe Method of Multiple PETE R J
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