Reply to the comment on “Sequence stratigraphy and onlap history of the Donets Basin, Ukraine: Insight into Carboniferous icehouse dynamics”

Abstract

Ruban (this issue) raises two concerns regarding the onlap–offlap curve recently published by Eros et al. (2012) for the Donets Basin. One issue questions the use of the Carboniferous timescale presented in Eros et al. (2012) given that it differs from that of the Geologic Time Scale 2004 (Davydov et al., 2005). The second issue addresses three discrepancies between the Donets curve and “the available global eustatic curve” of Haq and Schutter (2008), bringing into question the degree to which the Donets onlap–offlap history might record regional tectonism to continental-scale mantle dynamics over glacioeustasy. The Carboniferous timescale (Davydov et al., 2010) used by Eros et al. (2012) incorporates new high-precision ID-TIMS U–Pb dates from tonsteins collected throughout the Donets Basin that are tied to stratigraphic sections and sequences referenced in Eros et al. (2012). This time-scale forms the basis of the Carboniferous interval in the latest edition of the Geologic Timescale 2012 (Davydov et al., 2012), which we consider the most appropriate for use in Carboniferous studies. Here we present a high-resolution correlation between the onlap and sea-level histories for the U.S. Midcontinent (Ross and Ross, 1987; Heckel, 2008), the Donets Basin, and the Pennine Basin (Waters and Condon, 2012) made possible by recently published chronostratigraphic constraints (Davydov et al., 2010; Schmitz and Davydov, 2012). This robust chronostratigraphically constrained comparison argues for a dominant eustatic driver on the observed hierarchy of stratigraphic cyclicity and inferred sea level variations on the 105 and 106-year scale in minimally the cross-Pangaean paleotropical regions. Existing discrepancies between these correlated records and the Late Paleozoic record of ‘modal mean of change in sea level’ (Haq and Schutter, 2008) awaits future inter-regional correlations of radiometrically and biostratigraphically well-constrained Carboniferous successions.