Evolution of the marine stable carbon-isotope record during the early Cretaceous: A focus on the late Hauterivian and Barremian in the Tethyan realm

Abstract

In order to improve our understanding of the relationships between the late Hauterivian oceanic anoxic Faraoni event, contemporaneous platform drowning along the northern Tethyan margin and global environmental change in general, we established high-resolution δ 13 C and δ 18 O curves for the late Hauterivian and the entire Barremian stage. These data were obtained from whole-rock carbonate samples from the Veveyse de Châtel-Saint-Denis section (Switzerland), the Fiume-Bosso section and the nearby Gorgo a Cerbara section (central Italy), and the Angles section (Barremian stratotype, France).We observe an increase of 0.3‰ in mean δ 13 C values within sediments from the middle Hauterivian Subsaynella sayni ammonite zone to the Hauterivian-Barremian boundary; δ 13 C values remain essentially stable during the early Barremian. During the latest early Barremian and most of the late Barremian, δ 13 C values increase slowly (until the Imerites giraudi zone) and the latest Barremian is characterized by a negative trend in δ 13 C values, with minimal values at the Barremian-Aptian boundary. During the earliest Aptian, δ 13 C mean values start to rise again and attain + 2.25‰. We interpret the evolution of the δ 13 C record as resulting from the interaction between changes in the carbon cycle in the Tethyan basin and the adjacent platforms and continents. In particular, changes towards warmer and more humid conditions on the continent and coeval phases of platform drowning along the northern Tethyan margin may have contributed to enhance the oceanic dissolved inorganic carbon (DIC) reservoir which may have pushed the δ 13 C record towards more negative values and exerted a general attenuation on the δ 13 C record. From this may have come the general change from a heterozoan to a photozoan carbonate platform community, which influenced the evolution in δ 13 C values by increasing the export of aragonite and diminishing export of dissolved organic carbon into the basins.

New data on the age of the installation of Urgonian-type carbonates along the northern Tethyan margin: biostratigraphy of the Chopf Member (Helvetic Alps, eastern Switzerland)

“…6. Carbon isotope correlation between the Alvier region and the Cismon APTICORE drilling (figure modified from [14], after the results of [6,14]), and proposition of a new biostratigraphic framework after the results from [11] and this study. [14], d'après les résultats de [6,14]), ainsi que la proposition d'une nouvelle zonation biostratigraphique résultant des travaux de cette note et de [11].…”

Platform-induced clay-mineral fractionation along a northern Tethyan basin-platform transect: implications for the interpretation of Early Cretaceous climate change (Late Hauterivian-Early Aptian)

“…The Faraoni Level displays features similar to other Oceanic Anoxic Events (OAE's; e.g., Schlanger and Jenkyns, 1976;Scholle and Arthur, 1980) such as the presence of finely laminated black-shale facies with TOC values of more than 10% in Italian sections. However, unlike other Cretaceous OAE's, the Faraoni Level is not associated with a carbon isotope excursion and only marked by an increase of 0.15& in sediments from the western Switzerland and southeastern France (Baudin et al, 1999;Godet et al, 2006); by comparison, the OAE1a (Early Aptian) is associated to a negative spike (amplitude of ca. À1.5&) followed by a positive excursion (amplitude of ca.…”

“…þ2&; e.g., Fö llmi et al, 2006). This is explained by a buffering effect on the marine d 13 C record, through accelerated water cycle and increased delivery of Dissolved Inorganic Carbon (DIC) to the ocean under more humid climate conditions (e.g., Bartley and Kah, 2004;Godet et al, 2006).…”

“…9). Effectively, Godet et al (2006) The evolution of kaolinite contents along the northern Tethyan margin from the late Early Barremian to the earliest Aptian reveals an ambiguous behaviour of this clay mineral: whereas the Late Barremian sedimentary record in the Western Swiss Jura is characterized by high kaolinite contents (Fig. 6 and Table 2), contemporaneous sediments deposited in the Vocontian trough are relatively impoverished in this mineral (Fig.…”

Pseudothurmanniid ammonites from quarries near Lietavská Lúčka and their stratigraphical significance (Late Hauterivian, Central Western Carpathians, Slovakia)

“…This is shown by stud ies of car bon iso tope stra tig ra phy (e.g., Weissert et al, 1998;Godet et al, 2006), biostratigraphy, sedimentology and se quence stra tig ra phy (e.g., Cecca et al, 1994;Baudin et al, 1999;Baudin, 2005;Bodin et al, 2006;Hoedemaeker, 2002Hoedemaeker, , 2013. In the Up per Hauterivian at the end of Ohmi Zone, in the area of the north ern Tethyan mar gin, a Highstand Sys tems Tract of ten com pletes the Faraoni anoxic oce anic event or level.…”