Climate changes, paleogeography and geological development of the northern part of Bulgarian Black Sea shelf and coast during the Quaternary

Abstract

The article represents a synthesized reconstruction of the geological development of the northern part of Bulgarian Black Sea shelf and coast during the Quaternary. Marine Quaternary sediments are considered as a component of the marine ecosystem that is strongly affected by the climate changes. As a result, changes in the stratigraphic and sedimentological characteristics of the Pleistocene sediments and in particular the Holocene deposits were recorded. During the Quaternary, which is characterized by short-term, cyclic climatic fluctuations, marine shelf sediments have sealed traces of the alternation of glacial and interglacial phases. Based on detailed lithostratigraphic and biostratigraphic analysis of mollusk fauna and pollen, not only are the complex dynamics of the transgressiveregressive cycles traced, but also their relationship to global and regional changes of climate and sea level is confirmed. As a result of an integrated lithofacies, biostratigraphic, and geomorphological analysis, the stratigraphic sequence of the Quaternary sediments is established as well paleogeographic conclusions are reached. Today, knowledge of natural processes such as coastal abrasion, landslides, storms, tsunami waves, etc., are directly linked to the geological risk forecast and correlate with the geoecology and sustainability of the environment in which we live. In this sense, the reconstruction of the components of the geological environment from the closest geological past – Pleistocene and Holocene, is key to forecast climate change and sea level today.