Late Coniacian- Early Campanian planktonic foraminiferal bioevents and biostratigraphy of the northern Tunisia

Abstract

Planktonic foraminifera were quantitatively analyzed across the Santonian succession and their boundaries at the Jebel Ennahli and Ettout sections, northern Tunisia. The continuous sedimentary succession is dominated by hemipelagic facies, allowing a good biostratigraphic correlation for this time interval. Fifty-fi fe planktonic foraminiferal species belonging to 13 genera have been identifi ed. The distribution pattern of 17 heterohelicids and 38 trochospiral forms reveals the identifi cation of 12 major bio-events and allows establishment of three zones based on heterohelicids and fi ve zones based on trochospiral forms. Trochospiral based zones are from the base to the top: 1) Dicarinella primitiva Interval Zone, 2) Dicarinella concavata Interval Zone, 3) Dicarinella asymetrica Total Range Zone, 4) Globotruncanita elevata/Globotruncana arca Concurrent Range Zone, and 5) Globotruncanita ventricosa Interval Zone. The heterohelicid planktonic foraminiferal zones are: 1) Pseudotextularia nuttalli Interval Zone, 2) Sigalia carpatica Interval Zone, and 3) Ventilabrella eggeri/Planoglobuliina manuelensis Concurrent Range Zone. The bioevents and planktonic foraminiferal zones were correlated with previously published works especially on Tunisia and other areas. The lowest occurrence (LO) of Dicarinella asymetrica is the only planktonic foraminiferal datum recorded across the Coniacian/Santonian boundary (CSB). It occurs slightly below the LO of the inoceramid Platyceramus cycloides cycloides representing a good proxy for the CSB. The Santonian/Campanian boundary in the studied sections is characterized by a major faunal turnover represented by the LO of Ventilabrella and Planoglobulina and the LO of Globotruncana and Globotruncanita slightly above. The boundary interval is also characterized by the highest occurrence (HO) of Sigalia, Dicarinella, and Whiteinella.

Coniacian-late Campanian Planktonic Events in the Duwi Formation, Red Sea Region, Egypt

“…It is marked also by the extinction of both Muricohedbergella flandrini and Dicarinella asymetrica.Remarks: Some authors as[62,63] have equated the first appearance of Globotruncanita elevata with different levels of the Santonian Stage in North Africa and Mediterranean regions. Recent works show the base of the Campanian[64][65][66] and present work is marked by first appearance of Globotruncanita elevata taxon. In Egypt, many authors reported previously that Globotruncanita elevata is marked the base of the Campanian Stage in most localities[9,58,60,67,68,].…”

“…The first appearance of Globotruncanita elevata as indicated the marker of this boundary means prograding to oligotrophic episodes [85]. The lower Campanian shows the real diversity and radiation of globotruncanids, contusotruncanids and many foraminferal species in Northern Africa and Mediterranean regions [63,64], so at this boundary, many of mid Cretaceous planktonic foraminiferal taxa extincted globally [21,63]. The definition of Santonian/Campanian boundary is still mater of discussion [86][87][88].…”

A quantitative look on northwestern Tethyan foraminiferal assemblages, Campanian Nierental Formation, Austria

“…Few high-resolution studies on general evolutionary trends, visible in the quantitative data from Campanian foraminifera communities exist. In general, most of quantitative studies on Late Cretaceous foraminiferal assemblages focus on developments around stage boundaries and/or events (e.g., Huber et al, 1999 ; Arz & Molina, 2001 ; Odin & Lamaurelle, 2001 ; Petrizzo, 2002a ; Caron et al, 2006 ; Elamri & Zaghbib-Turki, 2014 ; Elamri, Farouk & Zaghbib-Turki, 2014 ; Reolid et al, 2015 ). The vast majority deals with the Cretaceous- Paleogene turnover (e.g., Abramovich, Almogi-Labin & Benjamini, 1998 ; Li & Keller, 1998 ; Arenillas et al, 2000 ; Abramovich & Keller, 2002 ; Karoui-Yaakoub, Zaghbib-Turki & Keller, 2002 ; Premoli Silva, Emeis & Robertson, 2005 ; Gallala et al, 2009 ; Beiranvand & Ghasemi-Nejad, 2013 , see also Pardo & Keller, 2008 for a compilation of selected quantitative databases on the Cretaceous-Paaeogene boundary).…”