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  • 1
    Electronic Resource
    Electronic Resource
    Swath Bathymetry Processing of GLORI-B and SeaBeam 2000 (1997)
    Springer
    Marine geophysical researches 19 (1997), S. 407-419 
    Details
    ISSN: 1573-0581
    Keywords: GLORIA ; GLORI-B ; SeaBeam ; bathymetry processing ; Easter Island ; seamounts ; hotspot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract A new bathymetry processing software package has been developed to postprocess new GLORI-B swath bathymetry data using preexisting techniques. GLORI-B bathymetry is calculated using an interferometry (phase delay) method using the modified GLORIA towfish which has parallel rows of transducers on both sides. We describe four types of artifacts observed during the first use of this new system during Legs 5 and 6 of the Gloria Expedition which surveyed the fastest spreading segment of the global seafloor spreading system and the broad chain of volcanoes near Easter Island. These artifacts include cross-track bias, along-track bias, a 'dropped edge' effect, and random noise. We describe and illustrate how we minimize these artifacts. We merge the SeaBeam 2000 bathymetry data with the GLORI-B bathymetry data to produce a final bathymetric mosaic which covers about 243,400 km2 and shows a different style of diffuse widely spread volcanism not previously observed along hotspot chains. The data are used in several studies describing seamount morphology, elastic thickness of the lithosphere, tectonic and geochemical evolution of the area, and mantle flow from a hotspot to a superfast seafloor spreading center.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004246305121
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Side-Scan Processing of GLORI-B and SeaBeam 2000 (1997)
    Springer
    Marine geophysical researches 19 (1997), S. 397-405 
    Details
    ISSN: 1573-0581
    Keywords: GLORIA ; GLORI-B ; SeaBeam ; side-scan processing ; Easter Island ; seamounts ; hotspot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract A new side-scan processing software package has been developed to postprocess data from the new GLORI-B system and SeaBeam 2000 side-scan data using preexisting techniques. We describe the procedures used to process the side-scan data collected during Legs 5, 6 and 7 of the Gloria Expedition in the spring of 1993. The procedures included minimizing artifacts and merging the two types of side-scan data together. The final mosaic shows recent widespread volcanic flows over large areas of the seafloor, unlike any other volcanic chain surveyed on the seafloor. The side-scan data were also very useful in dredging young rocks which are described in recently submitted geochemical manuscripts. The unique style of widespread low-lying young volcanism is attributed to the combination of superfast seafloor spreading and an underlying hotspot channel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004238121051
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    A SeaMARC II survey of recent submarine volcanism near Easter Island (1990)
    Springer
    Marine geophysical researches 12 (1990), S. 297-315 
    Details
    ISSN: 1573-0581
    Keywords: Submarine volcanism ; hotspot ; Easter Island ; Easter Microplate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract SeaMARC II side-scan sonar data reveal that a large area of seafloor north and west of Easter Island has been disrupted by recent submarine volcanism. A large volcanic area begins approximately 60 km WNW of the island and extends for over 130 km to the west. The volcanic field is characterized by high backscatter intensity in the side-scan sonar records and is elevated 400–1000 m above the N-S seafloor fabric that surrounds it. This field, the Abu Volcanic Field, covers at least 2500 km2 and appears to consist of recent lava flows and small volcanoes. Backscatter intensity of the Abu Volcanic Field is similar to that of the adjacent ridge flank which is less than 0.4 Ma, suggesting a similar age for its formation. Two additional areas of high backscatter immediately north of Easter Island cover a combined area of over 300 km2. The sidescan sonar records show that these features are clearly of volcanic origin and are not debris flows from the nearby island. The flows are nearly 300 m thick and are morphologically similar to subaerial pahoehoe lava shields. Their high backscatter indicates that they are also the products of relatively recent submarine volcanic activity. The presence of these large areas of recent volcanism in the vicinity of Easter Island has important implications for the various models that have been proposed to explain the origin of the Easter Seamount Chain. In addition, the similar ages of Easter Island and the Easter Microplate suggest that the presence of a hotspot near or beneath this fast-spreading portion of the East Pacific Rise about 4.5 m.y. ago may have initiated the large-scale rift propagation that created the microplate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02428200
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    Paper (German National Licenses)
    Fulltext
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