Mesozoic to recent geological history of southern Crimea and the Eastern Black Sea region

Abstract

We provide a synthesis of stratigraphic data to unravel the history of the geological evolution of South Crimea in the Mesozoic and Cenozoic. The South Crimea Orogen consists of three major mega-sequences: (1) the Triassic–Early Jurassic; (2) the Aalenian–Bathonian; and (3) the Callovian–Eocene. The Late Triassic–Early Jurassic deposits formed in the environment of a forearc basin and a remnant basin. The Aalenian–Bathonian deposits formed above subduction extension and a volcanic belt. Three main Callovian–Eocene tectonic units can be identified in South Crimea: (1) the South Crimean Shelf Basin; (2) the Sudak Deepwater Trough; and (3) the Alchak–Kaya Shelf Basin at the northern margin of the Shatsky Ridge. The Oligocene–Quaternary deposits are considered to be syn-orogenic. A description of the anticipated stratigraphic units on the Shatsky Ridge is suggested for the Middle Jurassic, Callovian–Late Jurassic, Neocomian, Aptian–Albian, Late Cretaceous–Paleocene, Eocene and Maykopian. We propose a model for the geological history of the Eastern Black Sea Basin. Graben formed during the Late Barremian–Albian at the location of the future Eastern Black Sea Basin and a phase of volcanism occurred in the Albian. The main phase of rifting and spreading of oceanic crust took place during Cenomanian–Santonian time.Supplementary material: A Google Earth kmz file of the location of the outcrops and sections is available at http://www.geolsoc.org.uk/SUP18850

Tectonic Evolution of the Eastern Black Sea and Caucasus: an introduction

“…This leads to new interpretations of the structural relationships in Crimea and the timing of tectonic events. Evidence of the Cretaceous extensional tectonic regime responsible for the formation of the Black Sea is now clearly recognized onshore and, importantly, there was a tectonic shortening regime during the Paleocene-Early Eocene, before the main Middle Eocene limestone unconformity and subsequent compressional deformation, not mentioned by Nikishin et al (2015b) in their offshore data. Sydorenko et al (2016) report a geological interpretation of a regional seismic reflection profile acquired along the same transect and in association with the DOBRE2 WARR profile (labelled 8 in Fig.…”

“…The Crimea -Caucasus seismic zone, where earthquake foci deepen northwards, lies between the continental domains to the north and the crust underlain by anomalous upper mantle, suggesting that the latter is being thrust under the former in this intra-plate setting. Nikishin et al (2015b) link the onshore geology of the Crimean Peninsula with the subsurface geology of the eastern Black Sea, largely based on a set of regional seismic reflection profiles, and choose to discuss the Mesozoic and Cenozoic geological evolution of the area in terms of three stratigraphic mega-sequences: the Triassic -Early Jurassic; the Middle Jurassic; and the Late Jurassic -Eocene. By far the greatest attention is given to the last of these, which encompasses the key event of the formation of the eastern Black Sea basin, with an early extensional phase (graben formation according to these researchers) in the late Early Cretaceous, culminating with a magmatic event at the end of the Albian, and a main extensional phase in the early Late Cretaceous.…”

The position and age of flysch deposits in the Crimean Mountains (Southern Ukraine).

“…De pos its with huge olistoliths are well ex posed on a cliff edge to wards Novyi Svit (e.g., the Koba-Kaya cliff; Fig. 17A) -see the Callovian/Oxfordian car bon ate reef mas sif (Nikishin et al, 2015b), and on the cliff close to the light house in Novyi Svit (Fig. 17B).…”

“…Up per in the sec tion the 716 Nestor Oszczypko, Andrzej OEl¹czka, Ihor Bubniak, Barbara Olszewska and Ma³gorzata Garecka A -south ern ter mi na tion of the Kacha Up lift; B -Laspi Area; C -Ay-Petri and Yalta mas sifs, Dimerji Yayla; D -Karabi Yayla; E -east ern sec tor of the CM, east of Pryvitne; F -east ern sec tor of the CM, Vesele-Novyi Svit-Sudak red con glom er ates are re placed by grey de bris-flow con glom erates de pos ited in a sub ma rine coastal fan delta (Lalomov, 2007) or a Gilbert-type delta (Baraboshkin and Piskunov, 2010). The Demerji fan delta is a kind of half-graben cut by the Simferopol/Alushta Fault from the west, and edged to the east (Nikishin et al, 2015b).…”

“…The mea sure ments of palaeotransport di rec tions in the Bodrak Val ley show sup ply of clastic ma te rial from the NW. Dur ing the Early Ju ras sic (Nikishin, 2015b), marly/clay sed i ments were de pos ited in the north ern, shal low-wa ter part of the ba sin, lo cally fol lowed by the ac cu mu la tion of Lower/Mid dle Ju ras sic mudstones and claystones with coal-bear ing in ter ca lations (Pivovarov and Derenyuk, 1984;Bilecki, 2006a;Vergelska, 2016). This was fol lowed by the Mid dle Ju ras sic fold ing, up lift and vol ca nic ac tiv ity in the north ern sec tor of the CM.…”