We use cookies to ensure that we give you the best experience on our website. You can change your cookie settings at any time. Otherwise, we'll assume you're OK to continue.

Durham University

Department of Earth Sciences


Publication details for Dr Darren R. Gröcke

Ulicný, D., Jarvis, I., Gröcke, D. R., Cech, S., Laurin, J., Olde, K., Trabucho-Alexandre, J., Svábenická, L. & Pedentchouk, N. (2014). A high-resolution carbon-isotope record of the Turonian stage correlated to a siliciclastic basin fill: Implications for mid-Cretaceous sea-level change. Palaeogeography, Palaeoclimatology, Palaeoecology 405: 42-58.

Author(s) from Durham


Turonian strata of the Bohemian Cretaceous Basin, Central Europe, preserve a basin-scale record of shoreline transgressions and regressions, previously interpreted to have been strongly influenced by short-term eustatic cycles. Here, nearshore siliciclastic strata in two separate sub-basins are correlated to a multi-stratigraphic dataset generated from a new research core (Bch-1) drilled in offshore marine sediments of the central basin. A high-resolution δ13Corg record from Bch-1 is presented along with major- and minor-element proxies, TOC, carbonate content, terrestrial to marine palynomorph ratios, and detailed macro- and microfossil biostratigraphy. The 400 m thick Turonian through Lower Coniacian interval permits correlation to the highest-resolution C-isotope curves available: all carbon-isotope events demonstrated by δ13Ccarb studies in the British Chalk, NW Germany and other reference sections in Europe are recognized in the δ13Corg curve from Bch-1.

A number of short-term, basin-wide regressions in the Bohemian Cretaceous Basin, most likely reflecting eustatic falls, show a recurrence interval of 100 kyr or less. This is an order of magnitude shorter than the timing of sea-level falls inferred from the New Jersey margin and the Apulian platform, interpreted to be driven by glacioeustacy. The estimated magnitude of the Bohemian Basin sea-level falls, typically 10–20 m and generally < 40 m, indicates that the 2.4 Myr period suggested by others to generate 3rd-order cycles, is too long to be the principal cycle generating unconformities in rapidly-subsiding basins, where the rate of eustatic fall must exceed the subsidence rate. Unconformities in low-accommodation settings such as passive margins most likely represent amalgamated records of multiple cycles of sea-level fluctuations of 100 kyr scale, recognizable only in high-resolution datasets from expanded successions.

Comparison of the δ13C excursions to the interpreted sea-level record has not yielded a clear causal link. A long-term ‘background’ δ13C cycle shows a duration close to the 2.4 Myr long-eccentricity cycle, and shorter-term (1 Myr scale) highs and lows in δ13C appear to broadly correspond to intervals characterised by more pronounced short-term sea-level highs and lows, respectively. However, on the scale of intermediate to short-term δ13C fluctuations, no systematic relationship between δ13C and sea-level change can be demonstrated.