The zonal scheme initially established for the Tethyan area on the basis of well-calibrated Lower Cretaceous stratotypic and Vocontian sections in southeast France (Moullade, 1966, 1974) permitted refinement in the subdivision of the pelagic "upper Aptian" beds cored at Site 1049 (Tables T1, T2, T3). Four successive zones are now precisely identified: the Globigerinelloides ferreolensis Interval Zone, the Globigerinelloides algeriana Total Range Zone and the Planomalina cheniourensis Interval Zone, corresponding to the middle and upper part of the Gargasian (upper Aptian) substage, and the Ticinella bejaouaensis Interval Zone (pro parte), corresponding to the Clansayesian (latest Aptian) substage.
During the Second International Symposium on Cretaceous Stage Boundaries held in Brussels (8-16 September 1995), the Albian Working Group identified in the Vocontian area a possible G-S-S-P (global boundary stratotype section and point) for the lower boundary of the Albian Stage. The selected section, offering a wide range of paleontological features that could be used to define the boundary, is located at "Col de Pré-Guittard" (west of La Motte-Chalancon, Drôme, southeast France). However, in this section placement of the Aptian/Albian boundary is not yet precisely known (Hart et al., 1996). Therefore, the proposition of Moullade (1966), based on a precise upper Clansayesian/lowermost Albian ammonite calibration throughout the entire Vocontian realm, is still retained here despite the reservations of Bréhéret et al. (1986). As far as foraminifers are concerned, the Aptian/Albian boundary is thus placed within the T. bejaouaensis Zone. Due to the lack of any significant planktonic foraminiferal first occurrence within this interval, the "lower Albian" part of this zone (defining the Aptian/Albian boundary by its base) is indicated by the first occurrence of Pleurostomella subnodosa (Moullade, 1966; Sigal, 1977; Hart et al., 1996), a worldwide and easily identifiable benthic foraminifer.
The Hedbergella planispira Interval Zone and the Hedbergella rischi Interval Zone (pro parte) correspond to the "middle Albian." The morphologic transition from H. rischi to Ticinella primula does not occur in the Site 1049 material but was observed in Holes 1050C and 1052E (Tables T4, T5) within the Rotalipora ticinensis Interval Zone. The oldest Albian samples of Sites 1050 and 1052 yield R. ticinensis, suggesting that the recovered Leg 171 "upper Albian" is not complete; the lower part of the upper Albian was not reached, since the Ticinella praeticinensis and Rotalipora subticinensis Interval Zones are not found in these holes.
The first occurrence of Rotalipora appenninica coincides with that of Planomalina buxtorfi in Hole 1052E. According to Parize et al. (1998), the lower boundary of the Vraconian (= uppermost Albian) substage must be now placed at the first occurrence of R. subticinensis, and not at that of R. appenninica as formerly proposed by Moullade (1966). Biticinella breggiensis, generally not used as a zonal marker since it is not regularly represented in these upper Albian/lower Vraconian levels, is relatively common in Hole 1050C, ranging through the R. ticinensis and the base of R. appenninica Interval Zones.
All the Cenomanian zones defined in the Tethyan Realm are represented in Hole 1050C: the Rotalipora globotruncanoides Interval Zone ("lower Cenomanian"), the Rotalipora reicheli Interval Zone ("middle Cenomanian," pro parte), the Rotalipora cushmani Total Range Zone ("middle" to "upper Cenomanian") and the Whiteinella archaeocretacea Interval Zone, pro parte ("uppermost Cenomanian").
At the Brussels Symposium (1995) a new proposal recommended that the lower boundary of the Cenomanian Stage should be defined by the first appearance of the planktonic foraminifer Rotalipora globotruncanoides. Some problems still remain concerning the taxonomic definition of this species which is in the process of revision. In addition, it is necessary to better calibrate this bio-event with the ammonite biostratigraphy. On the basis of an integrated study of a section at "Mont Risou" (near Rosans/Moydans, Drôme, southeast France) (= "Col de Palluel" section in Moullade, 1966), proposed as a G-S-S-P, the following planktonic foraminifer bioevents—straddling the boundary—can be recognized (Gale et al., 1996): the simultaneous first appearance of Rotalipora gandolfii and Rotalipora tehamahensis (= our R. aff. globotruncanoides; Tables T4, T5), the last appearance of R. ticinensis, and the first appearance of R. globotruncanoides.
Such a succession of bioevents has been determined in Hole 1050C, but has not been determined exactly in Hole 1052E, in which the overlap between R. ticinensis and R. gandolfii was not observed.
The Cenomanian/Turonian boundary occurs only at Site 1050. Planktonic foraminifer abundance changes and stable isotopic geochemistry for this interval are reported in Huber et al. (1999).