Integrated stratigraphy across the Aptian-Albian boundary in the Marnes Bleues, at the Col de Pre-Guittard, Arnayon Drome), and at Tartonne (Alpes-de-Haute-Provence), France: a candidate Global Boundary Stratotype Section and boundary point for the base of the Albian Stage

The history of definition of the Aptian-Albian boundary is reviewed with pa rticular reference to the ammonite schemes of Brinkmann (1937), Breistroffe r (1947), Casey (1961a, 1996, 1999), Kemper (1982), Owen (1996, 1999), and Ruffell & Owen (1995). The classic sequence in the Hannover area of Germany described by Brinkmann (1937) is reviewed in the light of subsequent work. The definition of the base of the Albian Stage at the first occurrence of the ammonite Proleymeriella schrammeni (Jacob, 1907) is rejected as it can only be recognised over a limited area near Hannover; no more widely recogn ised secondary markers have been documented, and there is no permanent sect ion at the present rime. An alternative Aptian-Albian boundary, defined by the first occurrence of t he ammonite Leymeriella (L.) tardefurcata (d'Orbigny, 1841) in the expanded Marnes Bleues section at Tartonne, Alpes-de-Haute-Provence, France, is sug gested. The palynomorph, coccolith, planktonic foraminiferan, ammonite, and inocera mid bivalve sequence, organic and inorganic carbon, trace, rare earth, and major element record, oxygen and carbon isotope sequence, and strontium iso tope data are presented for sections at the Col de Pre-Guittard, Arnayon (D rome), and Tartonne (Alpes-de-Haute-Provence) and described in detail. The Pre-Guittard section, considered as a candidate Global Boundary Stratotype Section (GSS) for the base of the Albian Stage at the Second International Symposium on Cretaceous Stage Boundaries held in Brussels in September 1995 , provides a standard section for the boundary interval in SE France. It is , however, unsuitable as a GSS, as there is a hiatus at the critical level in the section. In contrast, the Tartonne section is a potential GSS. The B oundary Point for the base of the Albian Stage suggested here is the first criterion proposed at Brussels: the first appearance of the ammonite Leymer iella (L.) tardefurcata at the base of the Niveau Paquier within the expand ed Marnes Bleues sequence. The first appearance is only 60 cm above the las t record of its presumed ancestor, L. (L.) germanica Casey, 1957. So define d, the boundary lies within the Prediscosphaera columnata Nannofossil (NF) Zone NC/CC8, and the planktonic foraminiferal Hedbergella planispira Partia l Range Zone. There is no major or trace element event associated with the proposed bound ary, nor is there any distinctive oxygen or carbon isotopic signal. Stronti um isotope data from the Tartonne section are compatible with those elsewhe re in the basin, and show that the base of the Albian, defined by the first appearance of L. (L.) taudefurcata corresponds to an Sr-87/Sr-86 ratio of 0.707339 +/- 2. Systematic sections deal with a new palynomorph, calcareous nannofossils an d ammonites; full range data and taxonomic indices are given for the first two groups. (C) 2000 Academic Press.