Search results for "FOSS"

El registro fósil de vertebrados y patrimonio paleontológico más representativo de los pirineos occidentales

2019

Los Pirineos occidentales son un territorio con una notable diversidad geológica y un importante registro fósil, que constituye un gran archivo de paleobiodiversidad. En lo que respecta al registro fósil de vertebrados, los Pirineos occidentales (Región Vasco-Cantábrica, Cuenca de Pamplona y sector noroccidental de la Cuenca del Ebro) son relevantes tanto desde el punto de vista de los yacimientos paleontológicos como de las colecciones de fósiles procedentes de ellos. Varios yacimientos de vertebrados forman parte del Inventario de Lugares de Interés Geológico (LIG) con alto o muy alto interés paleontológico en la Comunidad Autónoma del País Vasco. Destacan los yacimientos de peces cretáci…

1988

The living freshwater gastropod Melanopsis dufouri (FERUSSAC) has two morphotypes. The study of chemical variation of trace-elements in this gastropod and its correlation with the environmental fluctuation are the aim of this paper. Due to the genus Melanopsis has an abundant fossil record during the Cenozoic, the results of the present work could be of paleoecological interest. Trace-elements are embodied in the shell during growth. The shell of M. dufouri has accretionary growth. There are several examples cited on circadian accretionary growth in invertebrate shells. However, in the present case and as a first conclusion, the accretion rate depends on the size of the shell. In a short-ti…

Long-term estimates of the energy-return-on-investment (EROI) of coal, oil, and gas global productions

2017

We use a price-based methodology to assess the global energy-return-on-investment (EROI) of coal, oil, and gas, from the beginning of their reported production (respectively 1800, 1860, and 1890) to 2012. It appears that the EROI of global oil and gas productions reached their maximum values in the 1930s–40s, respectively around 50:1 and 150:1, and have declined subsequently. Furthermore, we suggest that the EROI of global coal production has not yet reached its maximum value. Based on the original work of Dale et al. (2011), we then present a new theoretical dynamic expression of the EROI. Modifications of the original model were needed in order to perform calibrations on each of our price…

Testing a portable laser-induced breakdown spectroscopy system on geological samples.

2012

9 pages; International audience; This paper illustrates the potentialities of a home-made portable LIBS (laser-induced breakdown spectroscopy) instrument in Earth sciences, more particularly in geochemically recognizing (i) tephra layers in lacustrine sediments and (ii) fossilization processes in ammonites. Abundances for selected lines of Al, Ca, Fe, Ti, Ba and Na were determined in lacustrine chalk sediments of the Jura, where the Laacher See Tephra (LST) layer is recorded. A statistical treatment of elemental maps produced from the section of a sedimentary column containing the LST event allows instrumental conditions to be optimized. Accumulating spectra from close shot positions gives …

Bonneuil-en-France (95), Aéroport du Bourget, zone nord-ouest. Un village du haut Moyen Âge, une petite exploitation agricole gallo-romaine, une nécr…

2022

Les fouilles ont eu lieu en 2016-2017 sur une surface de près de 9 hectares. Elles faisaient suite au diagnostic de 2007 (RO : T. Capararro, Inrap) et à une première fouille réalisée en 2010 sur une surface de 1,5 hectares (RO : G. Bruley-Chabot, Inrap). Hormis quelques éléments épars du Paléolithique Moyen au Néolithique, les premières traces d'occupation remontent à l'âge du Bronze final (quelques fosses et un enclos circulaire de plus de 330 m2 ). Le Hallstatt et La Tène A sont représentés par un faible nombre de structure. Une importante nécropole date de La Tène B2-C1. Elle regroupe 42 inhumations et une probable crémation. Si les ossements sont pour la plupart très mal conservés, le m…

A new Meckel's cartilage from the Devonian Hangenberg black shale in Morocco and its position in chondrichthyan jaw morphospace.

2022

Fossil chondrichthyan remains are mostly known from their teeth, scales or fin spines only, whereas their cartilaginous endoskeletons require exceptional preservational conditions to become fossilized. While most cartilaginous remains of Famennian (Late Devonian) chondrichthyans were found in older layers of the eastern Anti-Atlas, such fossils were unknown from the Hangenberg black shale (HBS) and only a few chondrichthyan teeth had been found therein previously. Here, we describe a Meckel’s cartilage from the Hangenberg black shale in Morocco, which is the first fossil cartilage from these strata. Since no teeth or other skeletal elements have been found in articulation, we used elliptica…

Phylogeny of viroids, viroidlike satellite RNAs, and the viroidlike domain of hepatitis delta virus RNA.

1991

We report a phylogenetic study of viroids, some plant satellite RNAs, and the viroidlike domain of human hepatitis delta virus RNA. Our results support a monophyletic origin of these RNAs and are consistent with the hypothesis that they may be "living fossils" of a precellular RNA world. Moreover, the viroidlike domain of human hepatitis delta virus RNA appears closely related to the viroidlike satellite RNAs of plants, with which it shares some structural and functional properties. On the basis of our phylogenetic analysis, we propose a taxonomic classification of these RNAs.

A Life Cycle Environmental Impact Comparison between Traditional, Hybrid, and Electric Vehicles in the European Context

2021

Global warming (GW) and urban pollution focused a great interest on hybrid electric vehicles (HEVs) and battery electric vehicles (BEVs) as cleaner alternatives to traditional internal combustion engine vehicles (ICEVs). The environmental impact related to the use of both ICEV and HEV mainly depends on the fossil fuel used by the thermal engines, while, in the case of the BEV, depends on the energy sources employed to produce electricity. Moreover, the production phase of each vehicle may also have a relevant environmental impact, due to the manufacturing processes and the materials employed. Starting from these considerations, the authors carried out a fair comparison of the environmental …

Pollen and Plant Macroremain Analyses for the Reconstruction of Environmental Changes in the Early Metal Period

2006

A sharp increase in human population density and the same time fundamental changes in the location of settlement, moving away from earlier inhabited places points to significant changes in the environment. This period with a sharp decrease in anthropogenic indicators and poor records of slash and burn cultivation and field crop-growing is named “transition” period (Vasks et.al.1998) and indicates the lack of stable and continuous inhabitant sites. This phenomena can be explained by the small size of settlements at the Early Iron Age, expressed by a weak cultural layer and these could be defined as separate farmsteads. Modern farming practices, especially modern tillage, adversely affected t…

Non-marine invertebrate trace fossils from the Tertiary Calatayud- Teruel Basin, NE Spain. Reply

2021

We thank the comments of Dr Calzada. We think that this kind of discussions is very healthy to the Paleontology and it would be necessary to do it more frequently, so that thanks again for your example. It is true that some of the descriptions of ichnofossils in our work need further discussion and comments, but when we analysed several poorly-preserved specimens (such as the so-called Spongeliomorpha isp.) we preferred to make a quick introduction and describe them in open nomenclature. It was beyond the scope of our paper to make a revision of the ichnogenus with this kind of material, but we hope that Calzada's comments and our reply will improve some ideas concerning the ichnogenus Spon…