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showing 10 items of 44654 documents
Using growth and geochemical composition of Clathromorphum compactum to track multiscale North Atlantic hydro-climate variability
2020
International audience; Records of ocean/atmosphere dynamics over the past centuries are essential to understand processes driving climate variability. This is particularly true for the Northwest Atlantic which is a key region with an essential role in global climate regulation. Over the past two decades, coralline red algae have been increasingly used as environmental and climatic archives for the marine realm and hold the potential to extend long-term instrumental measurements. Here, we investigate the possibility to extract climate and environmental information from annual growth patterns and geochemical composition of the coralline red algae, Clathromorphum compactum, from Saint-Pierre …
Iberian Neolithic Networks: The Rise and Fall of the Cardial World
2017
Recent approaches have described the evolutionary dynamics of the first Neolithic societies as a cycle of rise and fall. Several authors, using mainly c14 dates as a demographic proxy, identified a general pattern of a boom in population coincident with the arrival of food production economies followed by a rapid decline some centuries afterwards in multiple European regions. Concerning Iberia, we also noted that this phenomenon correlates with an initial development of archaeological entities (i.e., ‘cultures’) over large areas (e.g. the Impresso-Cardial in West Mediterranean), followed by a phase of ‘cultural fragmentation’ by the end of Early Neolithic. These results in a picture of high…
Stage boundaries, global stratigraphy, and the time scale: towards a simplification
2004
International audience; This paper examines four facets of stratigraphic terminology and usage considered faulty and proposes corrective measures. The four perfectible areas are: (1) The system of dual nomenclature requiring discrete terminologies for the superpositional and temporal aspects of rock units. (2) The premise that a GSSP establishes the base of a stage as being coincident with the top of the preceding stage rather than simply defining it as the boundary between stages. (3) The rejection of supplementary (auxiliary) sections that would broaden the knowledge of a GSSP and enlarge the area in which it is easily usable. (4) The current dual system of nomenclature for Precambrian an…
Uneven Data Quality and the Earliest Occupation of Europe—the Case of Untermassfeld (Germany)
2017
AbstractThe database regarding the earliest occupation of Europe has increased significantly in quantity and quality of data points over the last two decades, mainly through the addition of new sites as a result of long-term systematic excavations and large-scale prospections of Early and early Middle Pleistocene exposures. The site distribution pattern suggests an ephemeral presence of hominins in the south of Europe from around one million years ago, with occasional short northward expansions along the western coastal areas when temperate conditions permitted. From around 600,000-700,000 years ago Acheulean artefacts appear in Europe and somewhat later hominin presence seems to pick up, w…
Regional provenance of dolerite prehistoric objects through mineral analysis
2016
Abstract A methodology based on the mineral analysis determination has been developed to identify the origin of dolerite stone outcrops collected to fabricate lithic objects during the Prehistoric period. The method is based on the use of inductively coupled plasma mass spectrometry (ICP-MS) to analyse rare earth elements (REE) and trace elements. Additionally a no destructive geochemical analysis based on X-ray fluorescence (XRF) was employed for major elements analysis. The aforementioned methodologies were applied to samples from different archaeological fields or natural outcrops located in the Mediterranean area of Spain, between Valencia and Alicante. Principal component analysis (PCA…
Micro-PIXE/PIGE analysis of Palaeolithic mammoth ivory: Potential chemical markers of provenance and relative dating
2014
Abstract Micro-Proton Induced X-ray and Gamma-ray Emission (micro-PIXE/PIGE) provide non-destructive methods for the evaluation of the major, minor and trace element compositions of archaeological material. The current study applies micro-PIXE/PIGE analysis to mammoth ivory artefacts from four Palaeolithic sites (Abri Castanet, Vogelherd Cave, Grottes de la Verpilliere I and II) in France and Germany in order to assess the effectiveness of this approach to material older than 30,000 y BP. It has thus far not been established whether such methods of analysis can yield results of scientific and archaeological interest on ivory material that has undergone such extended periods of diagenesis. T…
Electron Paramagnetic Resonance and petrographic analysis for dating Mesolithic and Neolithic pottery from Al Khiday (Sudan)
2016
Abstract Electron Paramagnetic Resonance (EPR) dating, like luminescence techniques, is based on the time-dependent accumulation of trapped charges at mineral defect centres. However, Fe(III) ions prevent the common Continuous Wave (CW-EPR) approach for dating pottery, which always contains iron. The Pulsed method (ED-EPR) allowed this limitation to be overcome, with recording of radiation-induced defect signals, as shown by increased signal intensity after artificial irradiation of samples. The method was applied to studying Mesolithic and Neolithic pottery from Al Khiday (Central Sudan), characterized by quartz-rich tempers and coming from dated contexts. As the occurrence of a natural ED…
Challenges in defining the base of Cambrian Series 2 and Stage 3
2017
Formal subdivision of the Cambrian System into four series and ten stages is in progress. The base of Cambrian Stage 3 (provisional), which is conterminous with the base of Cambrian Series 2 (provisional), is expected to be placed at a horizon close to the first appearance of trilobites, which marks the onset of the largest phase of the Cambrian explosion. Conceptually, an ideal boundary position would be marked by a significant and globally recognizable bioevent that divides the lower part of the Cambrian System into a sub-trilobitic Terreneuvian Series and a trilobite-dominated Series 2. If the level is to be identified principally through biostratigraphic means, its position also needs t…
Genomic transformation and social organization during the Copper Age–Bronze Age transition in southern Iberia
2021
Description
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…