Search results for "Turonian"

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

2010

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 events (d13C), nine bio-events were defined near the Cenomanian-Turonian transition, successively in ascending order: 1. LO Rotalipora cushmani, 2. Heterohelix bio-event, 3. FO Pseudaspidoceras pseudonodosoides, 4. LO P. pseudonodosoides, 5. LO Thalmanninella multiloculata, 6. “filaments” bio-event, Ce…

A North American ammonite fauna from the late Middle Turonian of Vaucluse and Gard, southern France: the Romaniceras mexicanum, Prionocyclus hyatti a…

2016

Abstract An unusual, exotic, ammonite fauna including Romaniceras mexicanum Jones, 1938, Prionocyclus hyatti (Stanton, 1894) and Coilopoceras cf. springeri Hyatt, 1903 is recorded from the late Middle Turonian of Vaucluse and Gard, southern France. It is the first record of this ammonite association outside the Gulf Coast region and the Western Interior of the United States of North America. Up to present, these species were considered as endemic to the Western Interior sea-way. The migration of numerous ammonites from North America to western Europe during the late Middle Turonian suggests it is linked to a transgressive event or to a short sea-level high.

Planktonic foraminifera biozones and isotope stratigraphy of the Cenomanian-Turonian boundary in the western part of the Kopet-Dagh Basin, NE Iran

2018

Abstract A biostratigraphic study based on the planktonic foraminifera and isotope stratigraphy of the Cenomanian-Turonian interval has been undertaken in the western part of the Kopet-Dagh Basin (NE Iran). In this research, two stratigraphic sections including: Maraveh Tappeh and Qareh Galdy have been sampled and studied. Based on planktonic foraminifera, three biozones were assigned to this interval. These are the Rotalipora cushmani Zone, Whiteinella archaeocretacea Zone and Helvetoglobotruncana helvetica Zone, These biostratigraphic data confirm a gradual faunal turnover of planktonic foraminifera, at the Cenomanian-Turonian boundary in Whiteinella archaeocretacea Zone characterized by:…

Albian flora from Archingeay-Les Nouillers (Charente-Maritime): comparison and synthesis of Cretaceous meso- and macro-remains from the Aquitaine Bas…

2017

International audience; Over recent decades, diverse structures ascribed to angiosperms, bennettitaleans, conifers, cycads, ginkgophytes and pteridosperms have been reported from the Cretaceous deposits of the Aquitaine Basin (southwestern France). However, Albian macrofloras remain uncommon in Aquitania as well as in France. The clay from the Archingeay-Les Nouillers quarries is one of the rare deposits of the Aquitaine Basin to yield Albian plant meso- and macro-remains. Although Albian plant-bearing beds are not accessible any more in these quarries, samples collected from excavations conducted at the end of the XXth century were deposited in the collections of the University of Rennes 1…

First record of the enigmatic coleoid genus Longibelus from Sakhalin (Far East Russia): a contribution to our understanding of Cretaceous coleoid hab…

2021

AbstractA newly collected specimen of the enigmatic coleoid genus Longibelus is recorded from lower Turonian strata along the River Shadrinka in Sakhalin (Russian Far East). To date, this is the first record of Late Cretaceous coleoid cephalopods from the island and, in fact, from the entire Pacific coast of the Russian Federation. Lithological characteristics, coupled with published geochemical analyses (δ13C and Corg content), suggest the habitat of this coleoid taxon to have been the middle to outer (i.e. distal) shelf. Its provenance from the stratigraphical level that is known as the Scaphites Event, characterised by a mass occurrence of Scaphites and Yesoites, may be indicative of occ…

The Caribbean Plateau and OAE2: Resolution of timing and trace metal release

2013

Ammonite faunas from condensed Cenomanian-Turonian sections (‘Tourtias’) in southern Belgium and northern France

2011

AbstractIn southern Belgium (Mons Basin and Tournai region) and northern France (area between Lille, Valenciennes and Maubeuge), condensed sequences have been referred to as ‘tourtias’ since the start of the nineteenth century. These levels correspond to a succession of trangressive systems tracts and generally appear as dark green, glauconitic and microconglomeratic facies. They are distributed all along the base of the more important transgressive systems tracts of the Cenomanian and basal Turonian from the Boulonnais (northwest France) to the Mons Basin (southern Belgium), through the Artois and Douaisis. Their age can now be determined more accurately by identification of their ammonite…

Zonation by ammonites and foraminifers of the Vraconnian-Turonian interval: A comparison of the Boreal and Tethyan domains (NW Europe / Central Tunis…

2008

International audience; Since the end of the 19th century the interval comprising the uppermost Upper Albian, the Cenomamian, the Turonian and the basal Coniacian has been subdivided, first into ammonite zones, then, beginning in the middle of the 20th century, into zones of planktonic foraminifera. These two groups, one macrofossil, the other microfossil, are particularly effective for bio-chronostratigraphy thanks to their rapid rates of evolution. But differences in the faunal makeup between the Boreal domain (northwestern Europe) and the Tethyan domain (Mediterranean) have for a long time hindered precise correlation of the two domains. Today, in a time interval covering about 16 millio…

New data on middle Turonian tuffeaux of southern Touraine and on their ammonites faunas.

2020

The knowledge of the Turonian stratotype, “from Saumur till Montrichard“, along the Loire and the Cher valleys waspublished in 2018 by Amédro et alii. Since then, the study of recent collecting of ammonites in southern Touraine provided significant informationto state more precisely the Turonian zonation. New outcrops are described at Bourgueil, Chinon, Loudun, Usseau, Sossay,Marigny-Marmande, Séligny and Ports-sur-Vienne where the following formations were recognized: the Amboise Chalk, the tuffeaux ofArdilliers, of Saumur, of Bourré and the Tuffeau Jaune de Touraine.In these southern countries, it is pointed out that: (1) more than the upper half of the Amboise Chalk appears like the Tuff…

Support for a Vraconnian Stage between the Albian sensu stricto and the Cenomanian (Cretaceous System)

2008

The geological scale for the middle Cretaceous currently used throughout the world was proposed by Alcide d'Orbigny in the XIXth century between the years 1842 and 1847 and establishes the succession of stages as Albian, Cenomanian and Turonian. In 1868 Renevier proposed that a supplemental chronostratigraphic division be intercalated between the Albian and the Cenomanian: the Vraconnian stage. This term was not generally accepted and after a period when it was referred to by Breistroffer (1936) as a substage constituting the upper part of the Albian, as an equivalent of the Stoliczkaia dispar ammonite Zone, its abandonment was "recommended" by the Conference on the Lower Cretaceous held in…