Multi-proxy record of orbital-scale changes in climate and sedimentation during the Weissert Event in the Valanginian Bersek Marl Formation (Gerecse Mts., Hungary)

Abstract

The Valanginian positive carbon isotope excursion and associated environmental changes, known as the Weissert Event, is the first in the series of Cretaceous Earth system perturbations. Here, we develop a multiproxy cyclostratigraphy from a 31.2-m-thick Upper Valanginian to lowermost Hauterivian section of the Bersek Marl Formation in Gerecse Mountains, Hungary, comprising alternating marlstone layers of varying clay and carbonate content. The bulk carbonate d13C signal shows sustained, elevated values (up to 2.7‰) up to 19.2 m, followed by a decreasing trend upsection. Together with biostratigraphic data, this suggests that the lower part of the section was deposited during the plateau phase of the Late Valanginian Weissert Event. Spectral analyses of the multiproxy dataset, including magnetic susceptibility measurements and gamma-ray spectroscopy on the lower part of the section, led to the identification of precession, obliquity, and long and short eccentricity signals. A mean sedimentation rate of 14 m/Myr was calculated based on astronomical tuning. The cyclicity in the proxy signals reflects dilution cycles induced by the fluctuating rate of detrital runoff into the basin. This supports the idea that orbitally forced humid-arid cycles controlled the pelagic alternating sedimentation during the Early Cretaceous throughout the Tethyan area.

A High‐Resolution Belemnite Geochemical Analysis of Early Cretaceous (Valanginian‐Hauterivian) Environmental and Climatic Perturbations

“…The volcanic activity associated with emplacement of the continental Paraná-Etendeka LIP has been considered as a trigger of environmental change associated with the Valanginian Weissert event (e.g., Bajnai et al, 2017;Charbonnier et al, 2017;Duchamp-Alphonse et al, 2007;Erba et al, 2004;Lini et al, 1992;Martinez et al, 2015;Weissert et al, 1998). It might be expected that δ 13 C-depleted volcanic CO 2 (with a δ 13 C of approximately À5‰; Kump & Arthur, 1999) from the Paraná-Etendeka would have resulted in the ocean/atmosphere recording a negative event.…”

Integrated calcareous nannofossil and ammonite data from the upper Barremian–lower Albian of the northeastern Transdanubian Range (central Hungary): Stratigraphical implications and consequences for dating tectonic events

“…The Bersek Hill sections (F} ozy, 1995;Bajnai et al, 2017) are beyond the scope of the present study for two reasons: they are older, i.e., up to the Toxancyloceras vandenheckii SMAZ, in contrast to younger sections investigated for the present study the age of which correspond to the Martellites sarasini SMAZ. Besides, detailed integrated ammonite, nannofossil and belemnite data of Bersek Hill were previously published by F} ozy and and F} ozy and Janssen (2009).…”

“…From the Barremian onwards, sandy input became dominant and led to deposition of the L abatlan Sandstone Formation. The stratigraphy, geochemistry and fossils of the two units were intensively studied by Fül€ op (1958,1997), F} ozy and , F} ozy and Janssen 2009and Bajnai et al (2017). In an isolated outcrop the lithostratigraphically different K€ osz€ or} uk} ob anya Conglomerate Member (KbC) on top of the formation is exposed.…”

Early Cretaceous Terrestrial Milankovitch Cycles in the Luanping Basin, North China and Time Constraints on Early Stage Jehol Biota Evolution

“…The Weissert Event, characterized by a positive marine d 13 C excursion and global cooling, is the first major Early Cretaceous Earth system perturbation in the geologic record (Erba et al, 2004;Gröcke et al, 2005;Gréselle et al, 2011;Föllmi, 2012;Bajnai et al, 2017;Price et al, 2018). It is thought to span as much as 5.85 from the start of the Late Valanginian to the end of the Early Hauterivian (Martinez et al, 2015).…”