Distinguishing between tectonic and periglacial deformations of quaternary continental deposits in Europe

Abstract

Recognising of tectonic deformations in Quaternary sediments is important for interpretating palaeoclimatic developments accurately. Distinguishing deformations caused by seismic processes from that induced by periglacial processes needs accurate observations. The present paper is a contribution to the understanding of the genesis and diagenesis of soft-sedimentary structures in continental areas that at times have been subjected to periglacial conditions. Field observations from active periglacial and seismic areas are integrated with relevant data from previous studies. Several morphological criteria are proposed to define purely periglacial, purely co-seismic and combined periglacial/seismic forms. A reappraisal of the origin of involutions and associated deformations within an intra-plate region of Europe with continuous low-level seismic activity provides evidence of regional tectonic events independent of the recurrent glacial loading during Quaternary times. Reanalysing of involutions provides a more accurate insight into the permafrost extent during the cold phases of Quaternary times, and also enables recognition of the zones where perturbations of seismic or tectonic origin prevail.