Comment on “Sequence stratigraphy and onlap history of the Donets Basin, Ukraine: Insight into Carboniferous icehouse dynamics” by J.M. Eros, I.P. Montañez, D.A. Osleger, V.I. Davydov, T.I. Nemyrovska, V.I. Poletaev and M.V. Zhykalyak [Palaeogeography, Pa

Each high-quality regional study of relative sea-level changes may contribute to the understanding of global eustatic mechanisms. In particular, it is intriguing to compare the Carboniferous sea-level changes established in the Donbass (a large domain in the southwest of Russia and the east of Ukraine) by Eros et al. (2012) with the available global eustatic curve. At least two significant discrepancies between these reconstructions are found. The long-term early Moscovian lowstand that is reported from the Donbass coincides with the global eustatic rise. In contrast, the early Bashkirian global sea-level lowstand occurred when the relative sea level did not experience any extraordinary fall in the Donbass. Sea-level fluctuations across the Mississippian/Pennsylvanian boundary also differed slightly. At other time intervals, the regional and global curves are comparable. It is possible to hypothesize that either the regional signatures of the global eustatic fluctuations were altered by tectonic activity (e.g., in the form of dynamic topography) or that the available eustatic curve is incorrect in some places. Only further broad inter-regional correlations of Carboniferous sequences will permit choosing between these hypotheses. And it is not excluded that some different conclusions would be drawn if the observed stratigraphy of the Donbass is instead caused by regional vertical tectonic motions.