The Fennoscandian geoid bulge and its correlation with land uplift and Moho depth

Sjöberg, Lars E.; Nord, Tomas; Fan, Huaan

doi:10.1029/gm082p0133

Cited by 5 publications

(5 citation statements)

References 8 publications

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“…ANo may be identified as a depression in the geoid, filtered to exclude long wavelengths due to mantle convection, and corrected for crustal structure. The most recent estimate is that of Sjoberg, Nord & Fan (1992), ANo z 5 m. Inserting this into ( l l ) , together with c = 0.8 and r = 750 km, we obtain an approximate value of the remaining land uplift of Aho w90 m .…”

Section: A Note On T H E R E M a I N I N G L A N D Upliftmentioning

confidence: 87%

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Recent postglacial rebound, gravity change and mantle flow in Fennoscandia

Ekman

Mäkinen

1996

Geophysical Journal International

128

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The recent postglacial rebound of Fennoscandia is investigated using sea-level data, levelling data and gravity data. In particular, an analysis is made of the repeated data obtained hitherto on the Fennoscandian land-uplift gravity line along latitude 63". Methods for this analysis include an iterative procedure for computing the relation between gravity change and absolute land uplift, the mass-flow parameter and the geoid rise; the remaining land uplift is also estimated.The mass-flow parameter c is used to characterize the relation between additional mass and additional volume due to rebound; it is a number between 0 and 1, 1 corresponding to full inflow of mantle below the rising crust, and 0 to no inflow but some kind of decompression. The main result is that c is significantly different from 0 at the 99 per cent level: we find c % 0.8. This means that models proposed of the present uplift based on pure decompression must be ruled out, and that a viscous inflow of mantle is a necessary part of the ongoing uplift process. On the other hand, this process might be more complicated than a pure viscous flow.

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Section: A Note On T H E R E M a I N I N G L A N D Upliftmentioning

confidence: 87%

“…The most recent estimate is that of Sjoberg, Nord & Fan (1992), ANo z 5 m. Inserting this into ( l l ) , together with c = 0.8 and r = 750 km, we obtain an approximate value of the remaining land uplift of Aho w90 m . The value of c is highly significantly different from that of proposed decompression models, c = 0.…”

Section: Aho = ___ Ano Crmentioning

confidence: 96%

Recent postglacial rebound, gravity change and mantle flow in Fennoscandia

Ekman

Mäkinen

1996

Geophysical Journal International

128

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“…Conversely, the study series by Sjöberg et al (1994aSjöberg et al ( , 1994b indicates that the Moho depth variations contribute only little to gravity field features in Fennoscandia. They applied rigorous integral formulas along with an updated Moho map and more recent geopotential models (OSU 89B and OSU 91A).…”

mentioning

confidence: 87%

“…The first 10 degrees of a geopotential model portray very long-wavelength features of the gravity field, being thus important for deep Earth studies. For the results of an almost similar study in Fennoscandia we refer to Sjöberg et al (1994aSjöberg et al ( , 1994b, though a different geopotential model and dissimilar limits of the spectral windows were utilized there.…”

Section: Comparisons Of Different Spectral Windows Of the Geoid Modelsmentioning

confidence: 99%

Effect of the GRACE satellite mission on gravity field studies in Fennoscandia and the Baltic Sea region

Ellmann¹

2004

Proceedings of the Estonian Academy of Sciences. Geology

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“…Discussions of the relation between the geoidal depression and the structure of the Moho were given in a series of studies, e.g. Sjöberg et al (1991, 1994), Nord (1992), and Nord & Sjöberg (1992). In these studies, an integral formulation and recent Moho maps were employed.…”

Section: Introductionmentioning

confidence: 99%

Structural effects of the crust on the geoid modelled using deep seismic sounding interpretations

Kakkuri

Wang

1998

Geophys. J. Int.

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According to the theory of isostasy, the Earth has a tendency to deform its surface in order to reach an equilibrium state. The land‐uplift phenomenon in the area of the Fennoscandian Shield is thought to be a process of this kind. The geoid, as an equipotential surface of the Earth’s gravity field, contains information on how much the Earth’s surface departs from the equilibrium state. In order to study the isostatic process through geoidal undulations, the structural effects of the crust on the geoid have to be investigated. The structure of the crust of the Fennoscandian Shield has been extensively explored by means of deep seismic sounding (DSS). The data obtained from DSS are used to construct a 3‐D seismic‐velocity structure model of the area’s crust. The velocity model is converted to a 3‐D density model using the empirical relationship that holds between seismic velocities and crustal mass densities. Structural effects are then estimated from the 3‐D density model. The structural effects computed from the crustal model show that the mass deficiency of the crust in Fennoscandia has caused a geoidal depression twice as deep as that observed from the gravimetric geoid. It proves again that the crust has been isostatically compensated by the upper mantle. In other words, an anomalously high‐density upper mantle must exist beneath Fennoscandia.

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The Fennoscandian geoid bulge and its correlation with land uplift and Moho depth

Cited by 5 publications

References 8 publications

Recent postglacial rebound, gravity change and mantle flow in Fennoscandia

Recent postglacial rebound, gravity change and mantle flow in Fennoscandia

Effect of the GRACE satellite mission on gravity field studies in Fennoscandia and the Baltic Sea region

Structural effects of the crust on the geoid modelled using deep seismic sounding interpretations

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