Thoughts and Speculations on Geodynamic Processes
The structural and stratigraphic record of the Arctic-North Atlantic borderlands and the Tethys domain reflects their complex geological evolution during which orogenic events, associated with the accretion of continental fragments and the collision of major continents, alternated with periods of wrench faulting and crustal extension. The latter resulted in the destruction of preexisting fold belts and culminated ultimately in the break-up of the newly formed continent assemblies, to a large extent along their Paleozoic megasuture zones. Yet, it should be noted that some of the Pangea break-up axes are quite discordant with the Paleozoic megasutures (e.g., North Atlantic) and cut even across the Precambrian basement grain (e.g., Labrador Sea-Baffin Bay).
The geological evolution of the different parts of the Arctic-North Atlantic and Tethys domains reflects, through time, repeated changes in their megatectonic setting and, correspondingly, changes in the geodynamic processes that governed the subsidence and/or destruction of sedimentary basins. Thus, in time and space, basins of different geotectonic origin developed. Some of these were stacked on top of one another while others were partly destroyed during subsequent tectonic events.
These changes can be related to an almost unbroken sequence of tectonic processes that preceded and accompanied the reorganization of plate boundaries during the late Paleozoic to Recent evolution of the Arctic-North Atlantic and Tethys realms. The main steps of these reorganizations are recapitulated in this chapter.