Calcareous nannoplankton proxies for palaeoenvironmental reconstruction of the Albian–Cenomanian succession in North-western Israel (Mount Carmel Region)

Abstract

Abstract We present data on the calcareous nannofossil distribution in the Albian–Cenomanian borehole CT8 obtained from the Carmel area, NW Israel. The nannofloral assemblage consists of 113 species, with Watznaueria spp. dominating the entire succession. The detailed calcareous nannofossil biostratigraphy of this section is established, and seven nannofossil (sub)zones are recognised. For the first time the age of the Tavasim Tuff (V2) is biostratigraphically identified as Late Albian. The quantitative analysis of the calcareous nannofossils suggests warm, open marine or coastal, mainly oligotrophic conditions throughout the entire succession of borehole CT8, with evident fluctuations of temperatures and fertility and a general trend towards cooling in the uppermost part of the sequence (Middle–Late Cenomanian). Temperature and nutrient variations correspond to those in the western Tethys, thus suggesting at least a supra-regional extent of processes detected in the Carmel Region. The biostratigraphy shows no evidence of hiatuses in the studied section, but the absence of positive carbon isotope anomalies associated with the Oceanic Anoxic Event (OAE) 1d and Mid-Cenomanian Event elsewhere suggests that the OAE 1d is possibly missing in the studied section due to a hiatus around the Isfiye Fm./Arqan Fm. boundary.