Isostasy as a tool to validate interpretations of regional geophysical datasets – application to the mid-Norwegian continental margin
Sofie Gradmann, Claudia Haase, Jörg Ebbing, 2017. "Isostasy as a tool to validate interpretations of regional geophysical datasets – application to the mid-Norwegian continental margin", The NE Atlantic Region. A Reappraisal of Crustal Structure, Tectonostratigraphy and Magmatic Evolution, G. Péron-Pinvidic, J. R. Hopper, T. Funck, M. S. Stoker, C. Gaina, J. C. Doornenbal, U. E. Árting
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Isostasy is a well understood concept, yet rarely applied to its full capacity in regional interpretations of crustal structures. In this study, we utilize a recent density model for the entire NE Atlantic, based on refraction seismic data and gravity inversion, to calculate isostatically balanced bathymetry along the mid-Norwegian margin. Since gravity and isostatically balanced elevation are independent observables but both depend on the underlying density model, consistencies and discrepancies point towards model deficits, erroneously interpreted or poorly understood areas.
Four areas of large isostatic residuals are identified. Along the outer Vøring Margin, a mass deficit points to more extensive high-density bodies or a shallower Moho than currently mapped. Farther seaward, along the Vøring Marginal High, a mass excess indicates inaccurate mapping of the continent–ocean boundary and surrounding structures. A number of eclogitic bodies along the proximal mid-Norwegian margin have been described in recent publications and their presence is now also confirmed by isostatic calculations. Major elevation and gravity residuals along the transition between the Vøring and Møre margins signify that the structure of this region is poorly understood and modifications to the mapped continent–ocean transition may be required.