Palaeo-stress regimes and structural framework during the Mesozoic-Cenozoic tectonic evolution of the Crimean Mountains (the northern margin of the Black Sea)

Abstract

• The Crimean Mtns (CM) are divided into two parts by a NW-SE oriented main fault zone. • Two systems of E-W and of NW-SE oriented faults were reactivated since the Cretaceous. • The reactivated structures control the Cenozoic inversion of CM. • The model shows the major role of indenter during the Cenozoic inversion. This paper presents a chronology of tectonic events in the Crimean Mountains (CM) based on a micro- (palaeo-stress) and macro-scale (tectonic structures) structural analysis since the Cretaceous. Recent studies have attempted to fit the geology of the CM into the geodynamic context of the subduction of the Neotethys plate beneath the Eurasian margin; however, these attempts remain difficult and controversial as they are based dominantly on stratigraphic analysis. New structural analysis results indicate that structural development within the CM was largely determined by the influence of pre-existing structures that occurred long before the Cretaceous rifting in the Black Sea (BS). This could explain the features of the geological structure in the Western and Eastern CM separated by the Alushta–Simferopol Fault Zone (ASFZ). New palaeo-stress analysis allows us to identify the trends and timing of the Mesozoic–Cenozoic tectonic deformations with greater precision. Superimposing the low-magnitude seismicity (M ≤ 3) with structures defined on the established geological cross-sections permit the localization of currently active structures. Considering both recent scientific achievements concerning the geology of the CM and the results of this study, we propose a qualitative model of the formation of the BS Basin and its inversion in the context of the BS-Greater Caucasus (GC). In this model, the Shatsky Ridge (ShR), moving to the north, acts as an indenter deforming the CM and the GC. The results are of practical importance for geodynamic modelling and hydrocarbon exploration .