Proposal for the recognition of boundaries between Cretaceous stages by means of planktonic foraminiferal biostratigraphy

Abstract

Planktonic foraminifera are a much used biostratigraphic tool for the subdivision of the Cretaceous System from the Albian upwards. A proposal is given for the recognition of Cretaceous stages, using major biostratigraphic events to mark their boundaries. Thus, the extinction of Globotruncanita calcarata marks the Maastrichtian - Campanian boundary; the extinction of Dicarinel/a asymetrica the Campanian -Santonian boundary; the entry of D. asymetrica the Santonian - Coniacian boundary; the entry of Dicarinella primitiva with Marginotruncana ex gr. renzi -sinuosa the Coniacian -Turonian boundary; the extinction of Rotalipora cushmani the Turonian - Cenomanian boundary; the extinction of Planomalina buxtorfi the Cenomanian - Albian boundary.

A New Epistemological Insight of the Coniacian-Santonian Oceanic Anoxic Event (OAE3)

“…Caron M. [16] established this zone to represent the early Coniacian and occupy the interval from the first occurrence of Dicarinella primitiva to the first occurrence of Dicarinella concavata. The majority of planktic foraminifera researchers have believed that Turonian-Coniacian boundary cannot be determined based on planktic foraminifera, but some others believed that the first occurrence of Marginotruncana sinuosa has been shown in Turonian-Coniacian boundary [26][27][28]. Robaszynski F. and Caron M. [17] recorded the first occurrence of both Dicarinella primitiva and Dicarinella concavata in the late Turonian after correlation with ammonite's species Subprionocyclus neptuni.…”

The Global Boundary Stratotype Section and Point (GSSP) of the Campanian Stage at Bottaccione (Gubbio, Italy) and its Auxiliary Sections: Seaford Head (UK), Bocieniec (Poland), Postalm (Austria), Smoky Hill, Kansas (U.S.A), Tepayac (Mexico)

“…Although M. testudinarius has a global distribution, it is virtually restricted to relatively shallow water chalks and is absent in deeper water and most clastic facies (Gale et al, 2008). Marks (1984) noted that stratigraphically diagnostic planktonic foraminifera of the Dicarinella lineage are absent from the Aquitaine sections but suggested that the extinction of Dicarinella asymetrica provided a widely identifiable marker for the top of the Santonian in deeper water Tethyan successions. Following the work of Premoli and Premoli Silva and Sliter (1995), it has been demonstrated that the base of magnetochron C33r is approximately coincident with the highest occurrence of D. asymetrica in the Scaglia Rossa at Gubbio, Italy.…”