Estimation of seamount compensation using satellite altimetry

Schwank, D. C.; Lazarewicz, A. R.

doi:10.1029/gl009i008p00907

Cited by 17 publications

(8 citation statements)

References 5 publications

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“… Oceanic plateaus (on‐ridge): Shatsky Rise, 145–135 Ma (Den et al 1969; Marks & Sandwell 1991; Sager & Han 1993; Nakanishi et al 1999; Sager et al 1999; Verzhbitskii & Merklin 2000); Hess Rise, ∼100 Ma (Windom et al 1981; Vallier et al 1983; Marks & Sandwell 1991); Manihiki Plateau, 124–118 Ma (Hussong et al 1979; Mahoney & Spencer 1991; Tarduno et al 1991; Coffin & Eldholm 1993; Ito & Clift 1998), with late‐stage reactivation at ∼70 Ma (Bercovici & Mahoney 1994; Ito & Clift 1998); Tumaotu Plateau, ∼40 Ma (Talandier & Okal 1987; Ito et al 1995; McNutt 1998; Patriat et al 2002). Volcanic groups forming at divergent plate boundaries (on‐ridge): Musicians, ∼95–75 Ma (Schwank & Lazarewicz 1982; Dixon et al 1983; Freedman & Parsons 1986; Kopp et al 2003) and the geophysical ages record a previously observed (Schwank & Lazarewicz 1982) north to south volcanic progression through time; Cobb hotspot trace, 20–0 Ma (e.g. Desonie & Duncan 1990); Foundation seamounts 20–0 Ma (Mammerickx 1992; Devey et al 1997; O'Connor et al 1998; Maia et al 2001; Maia & Hamed 2002); Guadalupe chain (e.g.…”

Section: Resultsmentioning

confidence: 79%

“…(ii) Volcanic groups forming at divergent plate boundaries (onridge): Musicians, ∼95-75 Ma (Schwank & Lazarewicz 1982;Dixon et al 1983;Kopp et al 2003) and the geophysical ages record a previously observed (Schwank & Lazarewicz 1982) north to south volcanic progression through time; Cobb hotspot trace, 20-0 Ma (e.g. Desonie & Duncan 1990); Foundation seamounts 20-0 Ma (Mammerickx 1992;Devey et al 1997;O'Connor et al 1998;Maia et al 2001;Maia & Hamed 2002); Guadalupe chain (e.g.…”

Section: Validationmentioning

confidence: 93%

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Pacific seamount volcanism in space and time

Hillier

2007

Geophysical Journal International

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S U M M A R YSeamounts constitute some of the most direct evidence about intraplate volcanism. As such, when seamounts formed and into which tectonic setting they erupted (i.e. on-ridge or off-ridge) are a useful reflection of how the properties of the lithosphere interact with magma generation in the fluid mantle beneath. Proportionately few seamounts are radiometrically dated however, and these tend to be recently active.In order to more representatively sample and better understand Pacific seamount volcanism this paper estimates the eruption ages (t volc ) of 2706 volcanoes via automated estimates of lithospheric strength. Lithospheric strength (GTR rel ) is deduced from the ratio of gravity to topography above the summits of volcanoes, and is shown to correlate with seafloor age at the time of volcanic loading ( t) at 61 sites where radiometric constraints upon t exist. A trend of GT R rel = 0.09825 √ t + 0.20251 fits data for these 61, and with seafloor age (t s f ) known, can date the 2706 volcanoes; t volc = t s f − t.Widespread recurrences of volcanism proximal to older features (e.g. the Cook-Austral alignment in French Polynesia) suggest that the lithosphere exerts a significant element of control upon the location of volcanism, and that magmatic throughput leaves the lithosphere more susceptible to the passage of future melts. Observations also prompt speculation that: the Tavara seamounts share morphological characteristics and isostatic compensation state with the Musicians, and probably formed similarly; the Easter Island chain may be a modern analogy to the Cross-Lines; a Musicians -South Hawaiian seamounts alignment may be deflecting the Hawaiian hotspot trace.

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Section: Resultsmentioning

confidence: 79%

Section: Validationmentioning

confidence: 93%

Pacific seamount volcanism in space and time

Hillier

2007

Geophysical Journal International

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“…Schwank and Lazarewicz, 1982]. This is also a consequence of the one-dimensional approximation, since the actual conical seamount has mass deficiencies to both right and left of the satellite track relative to the assumed infinite two-dimensional ridge.…”

Section: The Predicted Height Of Seamounts Varies By Approximately ñ5mentioning

confidence: 87%

Bathymetric prediction from SEASAT altimeter data

et al. 1983

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The linear response function technique is used to analyze two 1300‐km tracks of SEASAT altimeter data and corresponding bathymetry in the Musician Seamounts region north of Hawaii. Bathymetry and geoid height are highly correlated in the 50‐ to 300‐km wavelength range. A predictive filter is developed which can operate on SEASAT altimetry in poorly surveyed oceanic regions to indicate the presence of major bathymétrie anomalies. Modeling of the bathymetry‐geoid correlation in the Musician region is attempted using the elastic plate model. The flexural rigidity D of the plate is not well constrained by our data but appears to lie in the range 5×1021 N m ‐ 5×1022 N m at the time of loading. Since the Musician Seamounts and the crust on which they lie are both Late Cretaceous in age, this value represents the effective flexural rigidity of very young lithosphere that was ‘frozen in’ at the time of voicanism, The modeling indicates that the general form of a predictive filter will strongly depend on various geologic parameters, especially the effective flexural rigidity. Hence, some a priori geologic constraints are necessary to estimate successfully the bathymetry from the altimeter data. Alternately, if high‐quality bathymetry is available, a crude estimate of the age of loading (i.e., voicanism) can be made from the altimeter data.

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“…It is therefore somewhat surprising that attempts have recently been made to predict the shape of uncharted seamounts directly from Seasat altimeter data [e.g., Schwank and Lazarewicz, 1982;Groeger, 1981]. In these studies, digital filters are constructed to identify seamount signatures in satellite-derived geoid data.…”

Section: Discussionmentioning

confidence: 99%

On geoid heights and flexure of the lithosphere at seamounts

Watts¹,

Ribe²

1984

J. Geophys. Res.

115

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The sea surface height has now been mapped to an accuracy of better than + 1 m by using radar altimeters on board orbiting satellites. The major influence on the mean sea surface height is the marine geoid which is an equipotential surface. We have carried out preliminary studies of how oceanic volcanoes, which rise above the ocean floor as isolated seamounts and oceanic islands or linear ridges, contribute to the marine geoid. Simple one-and two-dimensional models have been constructed in which it is assumed that the oceanic lithosphere responds to volcanic loads as a thin elastic plate overlying a weak fluid substratum. Previous studies based on gravity and bathymetry data and uplift/subsidence patterns show that the effective flexural rigidity of oceanic lithosphere and the equivalent elastic thickness T e increase with the age of the lithosphere at the time of loading. The models predict that isolated seamounts emplaced on relatively young lithosphere on or near a mid-ocean ridge crest will be associated with relatively low amplitude geoid anomalies (about 0.4-0.5 m/km of height), while seamounts formed on relatively old lithosphere, on ridge flanks, will be associated with much higher amplitude anomalies (1.4-1.5 m/km). Studies of the Seasat altimetric geoid prepared by NASA's Jet Propulsion Laboratory support these model predictions; geoid amplitudes are relatively low over the Mid-Pacific Mountains and Line Islands, which formed on or near a mid-ocean ridge crest, and relatively high over the Magellan Seamounts and Wake Guyots, which formed off ridge. Direct modeling of the altimetric geoid over these features is complicated, however, by the wide spacing of the satellite tracks (which can exceed 100 km) and poor bathymetric control beneath individual satellite tracks. In regions where multibeam bathymetric surveys are available, models can be constructed that fit the altimetric geoid to better than + 1 m. Studies of geoid anomalies over the Emperor seamount chain, for example, suggest that these seamounts formed on 20-30 Ma old oceanic lithosphere, while anomalies over the Louisville ridge and the Hawaiian ridge suggest that these seamounts formed on lithosphere older than about 80 Ma. This indicates that geoid anomalies over bathymetric features depend not only on the crustal structure prior to loading and the overall shape and density of the features but also on their tectonic setting. We examine the implications of these results to studies which attempt (1) to separate temporal variations of the sea surface due to oceanographic effects, (2) to predict seamounts directly from satellitederived gravity_and geoid data, and (3) to isolate the geoid effects of deep processes occurring beneath the lithosphere such as those due to mantle convection. With the advent of satellite altimetry, however, it became possible to determine accurately the intermediate-wavelength gravitational field in oceanic regions through direct measurements of the sea surface height. Satellite radar altimeters, such as used during NASA...

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Estimation of seamount compensation using satellite altimetry

Cited by 17 publications

References 5 publications

Pacific seamount volcanism in space and time

Pacific seamount volcanism in space and time

Bathymetric prediction from SEASAT altimeter data

On geoid heights and flexure of the lithosphere at seamounts

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