Search results for "Earth"
showing 10 items of 12204 documents
Pseudoshasticrioceras bersaci nov. sp. (Ammonoidea, Gassendiceratinae), and new ammonite biohorizon for the Upper Barremian of southeastern France
2009
International audience; Research in the Feraudianus Subzone of the Sartousiana Zone of the Barremian stage led to the discovery of a new species of Pseudoshasticrioceras: P. bersaci nov. sp. Its study provides evidence concerning the developments of the latest Gassendiceratinae BERT et alii, 2006, and the relationship between the genus Pseudoshasticrioceras DELANOY, 1998, and Gassendiceras BERT et alii, 2006. In particular, this new species is derived from Pseudoshasticrioceras magnini (DELANOY, 1992) by a minor revision in the processes of ontogenesis (retardation of ornamentation - neoteny). However, the evolution towards Pseudoshasticrioceras autrani DELANOY, 1998, implies a "failure" in…
Burned bones forensic investigations employing near infrared spectroscopy
2017
The use of near infrared (NIR) spectroscopy was evaluated, by using chemometric tools, for the study of the environmental impact on burned bones. Spectra of internal and external parts of burned bones, together with sediment samples, were treated by Principal Component Analysis and cluster classification as exploratory techniques to select burned bone samples, less affected by environmental processes, to properly carry out forensic studies. Partial Least Square Discriminant Analysis was used to build a model to classify bone samples based on their burning conditions, providing an efficient and accurate method to discern calcined and carbonized bone. Additionally, Partial Least Square regres…
Integrated bio- and carbon-isotope stratigraphy of the Upper Cretaceous Gurpi Formation (Iran): A new reference for the eastern Tethys and its implic…
2018
29 pages; International audience; A high-resolution stratigraphic analysis of the Upper Cretaceous Gurpi Formation has been undertaken in the Shahneshin section (Zagros Basin, Iran). New results on calcareous nannofossils, planktic foraminifers, dinoflagellate cysts and high-resolution carbon and oxygen stable isotopes form the basis of a reference section for the eastern Tethys that spans the upper Coniacian to the late Danian. Carbon-isotope correlation to Gubbio, Italy and the NW German chalk allows for the identification of many isotopic events as well as for the definition of new events in the Campanian and Maastrichtian. Our results allow for a review of the accurate position of the C…
New ichnites from the Middle Triassic of the Iberian Ranges (Spain): paleoenvironmental and paleogeographical implications
2010
17 pages; International audience; The Iberian Basin or its present-day expression, the Iberian Ranges, was refilled with red bed sediments of alluvial origin during the late Olenekian–Anisian period represented by the Cañizar (Olenekian–Anisian) and Eslida (Anisian) Formations, both commonly known as Buntsandstein facies. In the late part of the Anisian, the Tethys Sea reached the eastern side of the Iberian microplate, represented by the shallow marine facies of the Landete and Cañete Formations, also called Muschelkalk facies. The ichnites studied in this paper belong to the Anisian continental-marine transition in the SE Iberian Ranges. The Cañizar Formation shows the oldest Triassic foo…
Reconstructing early Holocene seasonal bottom-water temperatures in the northern North Sea using stable oxygen isotope records of Arctica islandica s…
2021
The knowledge of seasonal temperature variability in the ocean is essential for understanding climate and its response to forcing factors. Time intervals with highly dynamic climate and increased seasonal forcing such as the early Holocene are of particular interest. Yet, the temporal resolution of most existing climate records is not sufficient to reconstruct temperature seasonality. Here, we present the first seasonally resolved, early Holocene, bottom-water temperature record from the Viking Bank in the northern North Sea. The reconstruction is based on the stable oxygen isotope data (δ18Oshell) of two crossdated, radiocarbon-dated subfossil shells of Arctica islandica (Bivalvia). Oxygen…
Hydrothermalism in the Tyrrhenian Sea: Inorganic and microbial sulfur cycling as revealed by geochemical and multiple sulfur isotope data
2011
15 pages; International audience; The Palinuro volcanic complex and the Panarea hydrothermal field, both located in the Tyrrhenian Sea (Italy), are associated with island arc magmatism and characterized by polymetallic sulfide mineralization. Dissolved sulfide concentrations, pH, and Eh measured in porewaters at both sites reveal a variable hydrothermal influence on porewater chemistry. Multiple sulfur isotopic measurements for disseminated sulfides (CRS: chromium reducible sulfur) extracted from sediments at Palinuro yielded a broad range in δ34S range between −29.8 and +10.2‰ and Δ33S values between+0.015 and+0.134‰. In contrast, sediments at Panarea exhibit a much smaller range in δ34SCR…
Morphology and preliminary biomechanical interpretation of mandibular sutures in Metoposaurus krasiejowensis (Temnospondyli, Stereospondyli) from the…
2019
Altres ajuts: CERCA Programme/Generalitat de Catalunya The morphology of the mandibular sutures in the Late Triassic temnospondyl Metoposaurus krasiejowensis has been examined in order to determine their role in mandible biomechanics. Until now, no histological studies of mandibular sutures in extinct vertebrates were performed, in contrast to cranial sutures. As a consequence, mandibular suture interpretations herein are based mainly on comparisons with previous studies of cranial sutures and with 3D cranial finite element analysis of this species. A total of 32 standard thin sections were studied under standard petrographic microscope observations in order to differentiate the morphology …
A little walk between Early Jurassic sponges and corals: a confusing morphological convergence.
2019
24 pages; International audience; Hispaniastraea Turnšek et Geyer, 1975 is a unique coral genus from the Early Jurassic Epoch (Liassic). Corals of this genus are characterised by a highly dominant major septum and a set of eleven minor septa that are very short or even abortive. Initially discovered in Spain, new samples of this genus were depicted from Morocco by Beauvais in 1980; however, this genus was interpreted as a synonym of Pseudoseptifer Fischer, 1970, a chaetetid sponge (i.e., a sponge with siliceous spicules embedded in a calcareous skeleton). The skeleton of Pseudoseptifer is composed of adjacent tubules that increase by fissiparity by means of a pseudoseptum. Based on the stud…
Characterization of recent marks produced on fossil bone surface during sullegic and trephic processes and their influence on taphonomic studies
2018
Different taphonomic processes throughout the history of a fossil assemblage may preserve, modify or destroy, particular palaeobiological traits, but these processes always increase taphonomic information of the past. Similarly, fossils are affected during later stages of taphonomic history, i.e. excavation, preparation, study and storage of fossils, known as sullegic and trephic phases. Tools used during excavation and preparation of fossils can damage them and produce marks on their surface. Some of these recent marks highly mimic taphonomic marks produced before excavation. Both modern and fossil marks lead to misinterpretations and erroneous conclusions when similarities are not clearly…
Taphonomic processes inconsistent with indigenous Mesolithic acculturation during the transition to the Neolithic in the Western Mediterranean
2018
Abstract We applied taphonomic analysis combined with geostatistical approaches to investigate the hypothesis that Cocina cave (Eastern Iberia) represents an acculturation context for the appearance of Neolithic Cardial pottery. In the 1970s, Fortea suggested that this important site was a prime example of acculturation because of the presence of early Neolithic pottery in late Mesolithic contexts. Since that time Cocina cave has been heralded as an example of indigenous hunter-gatherers incorporating Neolithic cultural elements into their lifeways. We analyzed the area excavated by Fortea in the 1970s by digitizing archaeological records and testing the spatial distribution of artifacts us…