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Université de Fribourg

Remarks on the identification of the Albian/Cenomanian boundary and taxonomic clarification of the planktonic foraminifera index species globotruncanoides, brotzeni and tehamaensis

Petrizzo, Maria Rose ; Caron, Michèle ; Silva, Isabella Premoli

In: Geological Magazine, 2015, vol. 152, no. 3, p. 521-536

The planktonic foraminifera assemblage across the Global Boundary Stratotype Section and Point (GSSP) for the base of the Cenomanian Stage defined at Mont Risou (Haute-Alpes in France) is here restudied to clarify the identification and stratigraphic distribution of Thalmanninella globotruncanoides ( = Rotalipora globotruncanoides Sigal, 1948) and Pseudothalmanninella tehamaensis ( =...

Université de Fribourg

Evidence for oxic conditions during oceanic anoxic event 2 in the northern Tethyan pelagic realm

Westermann, S. ; Caron, Michèle ; Fiet, N. ; Fleitmann, D. ; Matera, V. ; Adatte, T. ; Föllmi, K. B.

In: Cretaceous Research, 2010, vol. 31, no. 5, p. 500-514

Upper Cenomanian pelagic sediments from the northern Alpine Helvetic fold-and-thrust belt (northern Tethyan margin) coeval with Oceanic Anoxic Event (OAE) 2 are characterized by the temporal persistence of micrite sedimentation and lack of organic carbon-rich layers. We studied an expanded section in the Chrummflueschlucht (east of Euthal, Switzerland), which encompasses the OAE 2 time interval....

Université de Fribourg

The global bio-events at the Cenomanian-Turonian transition in the reduced Bahloul Formation of Bou Ghanem (central Tunisia)

Robaszynski, Francis ; Zagrarni, Mohamed Faouzi ; Caron, Michèle ; Amédro, Francis

In: Cretaceous Research, 2010, vol. 31, no. 1, p. 1-15

In central Tunisia, the thickness of the Bahloul Formation varies generally between 20 to 40 m such as for example, respectively, at wadi Smara near Kalaat Senan and at wadi Bahloul near Maktar. The thickness is also of several tens metres at Koudiat el Azreg near Jerissa and at Tajerouine. In these sites where the thickness of the Bahloul Formation is dilated, in addition to five geochemical...

Université de Fribourg

Revision of the planktonic foraminifera Pseudothalmanninella klausi (LEHMANN, 1966) and Globotruncanella semsalensis (CORMINBOEUF, 1961) and first scanning electron microscope (SEM) images of the holotypes

Spezzaferri, Silvia ; Caron, Michèle

In: Revue de Paléobiologie, 2008, vol. 27, no. 1, p. 81-88

The planktonic foraminifera Rotalipora klausi Lehmann, 1966 and Globotruncana? semsalensis Corminboeuf, 1961, were figuredonly by drawings and the specimens were never made publicly available, although deposited in the collections of the Departmentof Geosciences, Fribourg, Switzerland. We present here for the first time their Scanning Electron Microscope documentation andcomparison with the...

Université de Fribourg

Scanning electron microscope images of uncoated microfossils: applications, perspectives and limitations

Spezzaferri, Silvia ; Neururer, Christoph ; Pirkenseer, Claudius ; Grobéty, Bernard

In: The Journal of Foraminiferal Research, 2007, vol. 37, no. 3, p. 270-276

We present a recently developed method using a field emission scanning electron microscope (FEG) to view and photograph microfossil specimens that are not coated by conductive material. The FEG microscope provides high electron flux and offers the option to capture images at low beam voltage. Balancing incident energy with absorbed energy from the detector leads to charge-free images of...

Université de Fribourg

Dicarinella imbricata (Mornod 1949): First SEM documentation of the lost holotype and foraminiferal assemblage from the type horizon (Upper Cretaceous, Switzerland)

Caron, Michèle ; Spezzaferri, Silvia

In: Eclogae Geologicae Helvetiae, 2006, vol. 99, no. 3, p. 295-299

The foraminifer species Dicarinella imbricata, from the Upper Cretaceous of Switzerland, was established in 1949 by L. Mornod. The holotype was figured only by Mornod’s drawings and the specimen was never made available. As the holotype was missing since a long time, it was considered as lost and a neotype was established. However, the holotype was recently found.We present here the first...

Université de Fribourg

Scanning electron microscope documentation of the lost holotypes of Mornod, 1949: Thalmanninella reicheli and Rotalipora montsalvensis

Caron, Michèle ; Spezzaferri, Silvia

In: The Journal of Foraminiferal Research, 2006, vol. 36, no. 4, p. 374-378

The species Globotruncana (Rotalipora) reicheli and Gobotruncana (Rotalipora) montsalvensis, were established in 1949 by Mornod. The two holotypes were figured only by drawings and the specimens were never made publicly available. Since their first description, these two species have acquired great importance as biostratigraphic markers. However, holotypes had been considered as...

Université de Fribourg

Third-order depositional sequences reflecting Milankovitch cyclicity

Strasser, André ; Hillgärtner, Heiko ; Hug, Wolfgang ; Pittet, Bernard

In: Terra Nova, 2000, vol. 12(6), p. 303

The origin of third-order depositional sequences remains debatable, and in many cases it is not clear whether they were controlled by tectonic activity and/or by eustatic sea-level changes. In Oxfordian and Berriasian-Valanginian carbonate-dominated sections of Switzerland, France, Germany and Spain, high-resolution sequence-stratigraphic and cyclostratigraphic analyses show that the sedimentary...