Bringing pre-orogenic salt and rifts into the picture: What can we learn about the Eastern Alps and Western Carpathians?

Due to the complexity inherent to the systems, the interpretation of the structure of the Northern Calcareous Alps and Inner Western Carpathians has traditionally relied on assuming a simplified pre-contractional configuration. The assumptions made include, for instance, that stratigraphy was either layer-cake or that it varied linearly from proximal to distal facies, that there is no or only limited decoupling between cover and basement during extension, and that rift systems have a one-directional distribution from proximal to distal domains. In the case of the Eastern Alps and Western Carpathians, these starting assumptions require complex interpretations of the orogenic structure, many of which have internal contradictions such as conflicting orogenic vergence or the unresolved debate on presence and/or the location of Mesozoic oceanic domains.

We argue that by incorporating modern concepts of salt tectonics and of rift system development, some long-standing paradoxes in these orogens can be successfully addressed. In the Eastern Alps, the development of a salt-rich rift system can explain the origin of the pelagic Hallstatt facies without requiring the presence of an oceanic domain. In the Western Carpathians, the presence of salt in a hyper-extended rift system can explain the confusing relationships of the Silica and its neighboring tectonic units as well as the apparent absence of its original basement. Incorporating the non-linear development of rift systems in turn can explain the nature of Mesozoic oceanic domains, from the Eastern Alps to the Western Carpathians.

In this contribution we review the key aspects of salt tectonics and rift systems that we believe could contribute to the understanding of the Eastern Alps and Western Carpathians and how they may be explored for in other segments of the Dinaric-Caraptho-Balkan system.