Search results for "Fora"

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…

Surface and deep water conditions in the Sicily channel (central Mediterranean) at the time of sapropel S5 deposition

2011

New centennial-scale data of benthic foraminifera assemblages and of stable isotopes of foraminifera shells from the Sicily Channel, representative of surface and bottom waters, over the interval between about 140 and 110 kyr BP, are presented. During this period anoxia developed on the eastern Mediterranean basin and sapropel S5 deposited. Although anoxic sediments have not been deposited in the Sicily Channel, this area is strategic to study the character of intermediate waters, whose chemical-physical properties strongly precondition the eastern Mediterranean deep water formation. So far, no data from these water masses have been obtained, apart from the isotopic composition of shells of…

Biochronological and paleoenvironmental interest of foraminifera lived in restricted environments: application to the study of the western Mediterran…

2002

As a consequence ofthe Flandrian transgression, numerous littoral lakes were f since roughly 6000 BP in the western Mediterranean coast. This kind of environment is colonized, among other groups, by specialized forms of foraminifera. Some species arose in the Upper Tertiary, some others in the Pleistocene and others are exclusively Holocene. Two kinds ofenvironment are proposed in the colonization: one with very low salinity waters where agglutinated test species prevail and another one with brackish waters, dominated by calcareous test species. In addition, Trichohyalus aguayoi can be considered as an acmezone within the Holocene. We propose a cenozone formed by the following assemblage: A…

Middle Triassic carbonate platforms in eastern Iberia: Evolution of their fauna and palaeogeographic significance in the western Tethys

2015

Abstract This article reports the first integrated study of the Middle Triassic of Iberia, based on the stratigraphy, sedimentology, and fossil fauna of Muschelkalk facies of the Iberian Ranges and the Catalan Coastal Ranges in Spain. On the basis of this study, new palaeogeographic reconstructions of the westernmost Tethys are proposed, and the evolution of the different palaeogeographic domains of Iberia (e.g., Iberian, Mediterranean, and Levantine–Balearic) are described. In these domains, Muschelkalk facies record the development of wide carbonate platforms that were the consequence of the first two broad marine transgressions of the Mesozoic in Iberia, respectively, late Pelsonian–earl…

Middle Miocene foraminifera from Canals (Valencia, western Mediterranean). Biostratigraphic and palaeoenvironmental aspects

2020

The age and the palaeoenvironmental conditions of the tap marls outcroppings near the locality of Canals in the south of the Valencia Province (E Spain) are discussed. Based on the planktonic foraminifera assemblages, mainly the species Globorotalia praemenardii , these tap marls are dated as Serravallian in age (middle Miocene). The analysis of the foraminiferal assemblages suggests a relatively well-ventilated uppermiddle bathyal environment, with only a moderate oxygen deficiency throughout most of the studied section. The rather cool waters indicated by the planktonic foraminifera (e.g. Globigerina bulloides ) are compatible with the decreasing temperatures trend during the middle Mioce…

Benthic foraminifera and environmental changes in the Quaternary of the western Mediterranean coast: the core of Xeraco, Valencia, Spain

2020

The evolution of the benthic foraminiferal assemblages from a 60 m core drilled in the Quaternary lagoon of Xeraco (Valencia, Spain) is studied. Two moments of warm climate, high sea-level and maximal marine influence in the lagoon have been identified. The first one at the base of the core, punctuated by highly frequent changes during the Upper Pleistocene, and the other one in the upper end of the series during the Holocene. The presence of a middle core section with low diversity and a nearly total absence of marine foraminifers is interpreted as a regressive interval of cold climate conditions linked to a glacial stage.

A high-resolution record of the last deglaciation in the Sicily Channel based on foraminifera and calcareous nannofossil quantitative distribution

2003

Abstract Relative abundance fluctuations in planktic foraminiferal and calcareous nannofossil assemblages are reported on the basis of a high-resolution study of ODP Leg 160 Hole 963D, drilled in the Sicily Strait, near Capo Rossello (southern Sicily). With its 8 m of undisturbed sediments, the core covers the interval from 1.5 to 23 kyr, allowing a 50–100-yr sampling resolution. All the short warm and cold events and sub-events recorded in this time interval in the GRIP Greenland ice core and at several Mediterranean sites were recognized. On this basis, a total number of nine ecozones based on planktic foraminifera and seven ecozones based on calcareous nannofossils were identified. A sho…

L’isola come metafora: trasferimenti e scambi nello spazio mediterraneo

2009

Clastic vs. primary precipitated evaporites in the Messinian Sicilian basins

2006

Automated segmentation and description of the internal morphology of human permanent teeth by means of micro-CT

2020

High-resolution micro-computed tomography is a powerful tool to analyze and visualize the internal morphology of human permanent teeth. It is increasingly used for investigation of epidemiological questions to provide the dentist with the necessary information required for successful endodontic treatment. The aim of the present paper was to propose an image processing method to automate parts of the work needed to fully describe the internal morphology of human permanent teeth. One hundred and four human teeth were scanned on a high-resolution micro-CT scanner using an automatic specimen changer. Python code in a Jupyter notebook was used to verify and process the scans, prepare the dataset…