No abstract

The DOBRE project investigated the interplay of geologic and geodynamic processes that controlled the evolution of the Donbas fold belt, Ukraine, as an example of an inverted intracratonic rift basin. A deep seismic reflection profile provides an excellent image of the structure of the Donbas fold belt, which is the uplifted and compressionally deformed part of the late Paleozoic Pripyat-Dniepr-Donets basin. Both the effects of rifting and those of later structural inversion are recognized in the seismic and geologic data. The interpretation of the reflection data shows that the inversion of the Donbas fold belt occurred at the crustal scale as a mega-pop-up, which involved a major detachment fault through the entire crust and an associated back thrust. The DOBREflection image provides a simple concept of intracratonic basin inversion, the crustal pop-up being uplifted and internally deformed. The association of such a structure with inverted intracratonic basins such as the Donbas fold belt implies brittle deformation of relatively cold crust.

The salt tectonics of the Glueckstadt Graben has been investigated in relation to major tectonic events within the basin. The lithologic features of salt sections from Rotliegend, Zechstein and Keuper show that almost pure salt is prominent in the Zechstein, dominating diapiric movements that have influenced the regional evolution of the Glueckstadt Graben.

To understand the major structural features of the sedimentary cover and crystalline crust of the Lofoten‐Vesterålen margin and the northern part of the Vøring segment of the Mid‐Norwegian continental margin, a lithosphere‐scale 3‐D structural model has been constructed. This model extends from the exposed crystalline rocks of the Fennoscandian Shield in the east to the Cenozoic oceanic domain of the Norwegian‐Greenland Sea in the west, covering the Vestfjorden, Ribban, and Røst Basins and the northern parts of the Vøring Basin and Trøndelag Platform. All available published and/or released data have been used to set the initial 3‐D model which has been validated by means of 3‐D density forward modeling to obtain a gravity‐consistent 3‐D structural/density model. Results from the 3‐D density modeling reveal that relatively thick sedimentary rocks are present in the distal Røst Basin below the lava flows. The presence of a low‐density more than 20 km thick granitic body has been modeled within the middle‐upper crystalline crust beneath the eastern part of the Vestfjorden Basin and the adjacent mainland. Moreover, the results of the 3‐D density modeling indicate the presence of an atypical low‐density lithospheric mantle beneath a large part of the Lofoten‐Vesterålen margin which is required to fit the regional component of the modeled gravity with the observed one. The pronounced crustal feature within the model area is the Bivrost Lineament that appears to be the deeply seated lithosphere‐scale boundary that delineates clearly the Lofoten‐Vesterålen segment from the Vøring margin showing contrasting densities and crustal thicknesses.