TY  - JOUR
A1  - Helmond, Niels A. G. M. van
A1  - Sluijs, Appy
A1  - Sinninghe Damsté, Jaap S.
A1  - Reichart, Gert-Jan
A1  - Voigt, Silke
A1  - Erbacher, Jochen
A1  - Pross, Jörg
A1  - Brinkhuis, Henk
T1  - Freshwater discharge controlled deposition of Cenomanian-Turonian black shales on the NW European epicontinental shelf (Wunstorf, northern Germany)
T2  - Climate of the past
N2  - Global warming, changes in the hydrological cycle and enhanced marine primary productivity all have been invoked as having contributed to the occurrence of widespread ocean anoxia during the Cenomanian–Turonian oceanic anoxic event (OAE2; ~94 Ma), but disentangling these factors on a regional scale has remained problematic. In an attempt to separate these forcing factors, we generated palynological and organic geochemical records using a core spanning the OAE2 from Wunstorf, Lower Saxony Basin (LSB; northern Germany), which exhibits cyclic black shale–marl alternations related to the orbital precession cycle.
Despite the widely varying depositional conditions complicating the interpretation of the obtained records, TEX86H indicates that sea-surface temperature (SST) evolution in the LSB during OAE2 resembles that of previously studied sites throughout the proto-North Atlantic. Cooling during the so-called Plenus Cold Event interrupted black shale deposition during the early stages of OAE2. However, TEX86 does not vary significantly across black shale–marl alternations, suggesting that temperature variations did not force the formation of the cyclic black shale horizons. Relative (i.e., with respect to marine palynomorphs) and absolute abundances of pollen and spores are elevated during phases of black shale deposition, indicative of enhanced precipitation and run-off. High abundances of cysts from inferred heterotrophic and euryhaline dinoflagellates supports high run-off, which likely introduced additional nutrients to the epicontinental shelf resulting in elevated marine primary productivity.
We conclude that orbitally forced enhanced precipitation and run-off, in tandem with elevated marine primary productivity, were critical in cyclic black shale formation on the northern European epicontinental shelf and potentially for other OAE2 sections in the proto-Atlantic and Western Interior Seaway at similar latitudes as well.
Y1  - 2015
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/37224
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-372245
SN  - 1814-9332
N1  - © Author(s) 2015. This work is distributed under the Creative Commons Attribution 3.0 License.
VL  - 11
SP  - 495
EP  - 508
PB  - Copernicus Ges.
CY  - Katlenburg-Lindau
ER  -