Open AccessCrustal thicknesses in Fennoscandia
Author(s) -
Bungum H.,
Pirhonen S. E.,
Husebye E. S.
Publication year - 1980
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1980.tb02650.x
Subject(s) - geology , seismometer , seismology , bouguer anomaly , tectonics , terrane , post glacial rebound , crust , lithosphere , bay , geodesy , gravity anomaly , geomorphology , glacial period , geophysics , paleontology , oceanography , oil field
b As a supplement to seismic profiling surveys, crustal thicknesses have been estimated for 11 Fennoscandian seismograph stations equipped with three‐component long period instruments, using the so‐called spectral ratio technique of Phinney. The largest Moho depths, of the order of 45 km, were found for stations located in the north‐east areas of Norway and Sweden and in Finland, with a local maximum in the Bothnian Bay. The coastal area of south‐east Norway and Zealand, Denmark exhibit crustal thicknesses in the range 28–33 km. The agreement between our results and those obtained by conventional refraction profiling is good, when this comparison is restricted to profiles of lengths 300 km or more, and when the associated crustal thickness estimate is averaged over the central parts of the profiles in question. Also, a comparison between our results and other available geophysical information gives that the oldest tectonic provinces of the Baltic Shield also are characterized by relatively modest heat flow, and exhibit the greatest crustal thicknesses. Post‐glacial uplift data and large wavelength free air gravity data appear to be uncorrelated with crustal thickness. The same partly applies to Bouguer gravity anomalies, thus implying that the isostatic compensation mechanism in Fennoscandia is of both Airy and Pratt type.