CRUSTAL-SCALE POP-UP STRUCTURE IN CRATONIC LITHOSPHERE: DOBRE DEEP SEISMIC REFLECTION STUDY OF THE DONBAS FOLD BELT, UKRAINE

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 intracratortic 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.