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Is there evidence for magmatic underplating beneath the Oslo Rift?
Author(s) -
Ebbing Jörg,
Afework Yohannes,
Olesen Odleiv,
Nordgulen Øystein
Publication year - 2005
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.2004.00592.x
Subject(s) - rift , geology , bouguer anomaly , underplating , pangaea , crust , seismology , precambrian , permian , paleontology , lithosphere , tectonics , gravity anomaly , structural basin , oil field
We challenge some of the long‐standing beliefs related to the Permian Oslo Rift structure, often referred to as a case example/type locality for continental rifting. The crustal structure of the Oslo Rift was long presumed to be thinned Proterozoic crust overlying a Permian high‐density layer, interpreted as magmatic underplating. New data support an alternative view of the crustal structure in the Oslo Rift region. The Bouguer gravity high in the region shows a strong asymmetry: a steep, westward‐facing gradient to the west of the rift, and a much gentler eastern gradient. We present a 3D density model based on petrophysical and seismic information, which accounts for the Bouguer gravity high using an eastward extension of old Precambrian structures, without invoking a prominent magmatic underplated structure. Reactivation of old pre‐rift structures appears to be an important feature, affecting the evolution and location of the Permo‐Carboniferous Oslo Rift.